Endometrial Cancer Screening, Diagnosis, and Prognosis

Number: 0769

Table Of Contents

Policy

Scope of Policy

This Clinical Policy Bulletin addresses endometrial cancer screening, diagnosis, and prognosis.

1. Medical Necessity

   Aetna considers the following procedures medically necessary:

   1. Endometrial biopsy (sampling) for histological tissue examination in the diagnostic evaluation of abnormal uterine bleeding in women suspected of having endometrial hyperplasia or endometrial carcinoma; and for endometrial cancer surveillance in women with Lynch syndrome;
   2. Endometrial brush (Tao brush) as an acceptable alternative to an endometrial suction curette (e.g., Pipelle) for medically necessary endometrial sampling;
   3. Sentinel lymph node mapping for pathologic evaluation and surgical staging in persons with endometrial cancer, and endometrial intraepithelial neoplasia (EIN).

2. Experimental, Investigational, or Unproven

   Aetna considers the following tests experimental, investigational, or unproven because the effectiveness of these approaches has not been established (not an all-inclusive list):

   • Circulating adiponectin, leptin, and adiponectin-leptin ratio as biomarkers for the prevention, early diagnosis and disease monitoring of endometrial cancer
   • Circulating and endometrial tissue microRNA markers for the diagnosis and prognosis of endometrial cancer
   • Determination of circular RNAs expression for diagnosis of grade-3 endometrial cancer
   • DNA methylation for diagnosis of sporadic endometrial cancer
   • DNA methylation for screening of endometrial cancer
   • Endometrial biopsy (sampling) for the screening of endometrial cancer
   • Endometrial or cervical cytology performed in conjunction with endometrial histology (TruTestTM, GynecorTM, Glen Allen, VA) in the diagnostic evaluation of abnormal uterine bleeding in women suspected of having endometrial hyperplasia or endometrial carcinoma
   • FTO rs9939609 and HSD17B1 rs605059 gene polymorphism testing for the diagnosis of endometrial cancer
   • Immunohistochemistry for protein phosphatase and tensin homolog (PTEN) for differential diagnosis of benign and pre-malignant endometrial hyperplasia
   • Measurement of blood anti-Müllerian hormone (AMH) level for screening and diagnosis of endometrial cancer
   • Measurement of
     1. circulating YKL-40,
     2. serum human epididymis protein 4 (HE4), and
     3. urine microRNAs for diagnosis of endometrial cancer
   • Measurement of endometrial thickness as a screening test for endometrial carcinoma in asymptomatic post-menopausal women not using hormone replacement therapy
   • Measurement of L1 cell adhesion molecule (L1CAM) expression for prognosis of endometrial cancer
   • Measurement of neutrophil gelatinase-associated lipocalin level for the diagnosis of endometrial cancer
   • Measurements of telomeres and telomerase activity for the diagnosis and/or screening of endometrial cancer
   • Metabolomics (metabolic biomarkers) for diagnosis and prognosis of endometrial cancer
   • Polymorphism testing of the fat mass and obesity-associated (FTO) genes for screening and diagnosis of endometrial cancer
   • Single nucleotide polymorphism testing
   • UBE2C, WNT5a, and ZEB1 as biomarkers for prognosis of endometrial cancer.

3. Related Policies

   • CPB 0111 - Indocyanine Green Angiography
   • CPB 0140 - Genetic Testing
   • CPB 0352 - Tumor Markers
   • CPB 0433 - Herpes Simplex Virus
   • CPB 0443 - Cervical Cancer Screening and Diagnosis
   • CPB 0530 - Transvaginal Ultrasonography
   • CPB 0650 - Polymerase Chain Reaction Testing: Selected Indications

Background

Endometrial cancer is a common malignancy of the uterine lining and accounts for the vast majority of uterine cancer cases in the United States (Mager and McLean, 2026). It occurs most frequently in postmenopausal women, although incidence rates have been increasing in younger age groups. Abnormal uterine bleeding is the most common presenting symptom and often prompts clinical evaluation, leading to diagnosis at an early stage when prognosis is generally favorable (Mager and McLean, 2026). The diagnosis of endometrial cancer is based on clinical assessment and histopathologic examination of endometrial tissue, while prognosis is influenced by factors such as stage at diagnosis, histologic subtype, tumor grade, lymph node involvement, and molecular characteristics. Numerous biomarkers and molecular techniques are being investigated for screening, diagnosis, prognostication, and disease monitoring; however, the clinical utility of many of these approaches has not been established and continues to be evaluated (Anca-Stanciu et al., 2025).

The National Cancer Institute (NCI, 2008) has stated that there is insufficient evidence to establish whether a decrease in mortality from endometrial cancer occurs with screening by endometrial sampling. The NCI notes that, based on solid evidence, endometrial biopsy (sampling) may result in discomfort, bleeding, infection, and, in rare cases, uterine perforation. In addition, risks associated with false-positive test results include anxiety and additional diagnostic testing and surgery. Furthermore, endometrial cancers may be missed on endometrial sampling.

Endometrial sampling by means of biopsy for histological examination in the diagnostic evaluation of abnormal uterine bleeding in women suspected of having endometrial hyperplasia or endometrial carcinoma is a minimally invasive alternative to dilatation and curettage (D&C) or hysteroscopy. The Pipelle endometrial sampling device is the most popular method for sampling the endometrial lining (Guido, 2008). Various types of brushes have also been used for endometrial sampling. Although the brush appears to be as effective or better than other blind methods of endometrial sampling, these devices have been evaluated in only a few studies with small numbers of subjects (Tao, 1995; Tao, 1997; Critchley et al., 2004; Yang et al., 2002; Del Priore et al., 2001; Yang and Wan, 2000; Maksem et al., 2000). In one of the larger comparative trials, 101 women (aged 35 to 86 years) with clinical indications for endometrial biopsy underwent a brush biopsy (Tao Brush, Cook OB-GYN, Bloomington, IN) and a Pipelle biopsy (Cooper Surgical, Shelton, CT) during one office visit. Twenty-two had cancer or atypia; the others had benign diagnoses. When correlated with the final diagnosis, sensitivity for the Tao Brush and Pipelle were 95.5% and 86%, respectively, and specificity was 100% for both (Del Priore et al., 2001).

According to the company's website (Gynecor™, Glen Allen, VA), the TruTest™ for total uterine testing is the first test that is able to detect endometrial and cervical cancer, HPV, chlamydia, and gonorrhea from the same specimen. Using the Tao Brush, a sampling of the uterine lining is taken, and the brush is sent to Gynecor™ for both histology and cytology examination. The testing kit provided by Gynecor has one Tao Brush (used for the collection of endometrial tissue) and two cytobrushes (one is used to clean mucus and debris from the cervix, and the second is used for enhanced cell and tissue collection from the squamocolumnar junction of the uterine cervix). The Tao Brush is a Food and Drug Administration Class II device.

The use of histology for endometrial examination depends on having enough tissue to yield an accurate test result. However, a tissue specimen is sometimes hard to collect, especially in post-menopausal women. Gynecor fixative can be used for both histology and cytology. According to Gynecor's website, "Cytologies are very important because they add about 20% more information than is obtained with just the histology. Using this method, Gynecor has been able to diagnose ovarian carcinoma in transit, endometrial intraepithelial neoplasia, and endometrial intraepithelial carcinoma."

Maksem (1998) also reported on a case of ciliated endometrioid adenocarcinoma of the endometrium, diagnosed by endometrial brush biopsy and confirmed by histology.

In a subsequent paper, Maksem et al. (1999) reported on 7 women where liquid-fixed Tao brush cytological samples of the endometrium showing "small amounts of atypical epithelium with cancer-like nuclei" were found after hysterectomy to be associated with a variety of diagnoses, including 3 women with hyperplastic polyps with focal atypical complex hyperplasia, 1 woman with hyperplastic polyps with focal atypical simple hyperplasia, 1 woman with endometrial microcarcinoma, 1 woman with p-53 positive endometrial intraepithelial carcinoma, and 1 with endometrial intraepithelial neoplasia.

Van den Bosch et al. (1998) evaluated the value of cervical cytology in menopausal women at high risk for endometrial disease in 128 consecutive menopausal women presenting with uterine bleeding (n = 116) or in whom endometrial cells were found on a previous cervical cytology smear (n = 12). An endo- and ecto-cervical smear was taken before hysteroscopy with curettage, and the results of the cervical cytology were compared with the endometrial histology. Endometrial carcinoma was diagnosed by endometrial sampling in six women. In two of these cases, cervical smears did not contain endometrial cells. The presence of endometrial cells on ecto-cervical cytology showed a sensitivity of 67% and a specificity of 78% for endometrial carcinoma versus 80% and 76%, respectively, for endo-cervical cytology. The positive predictive value for endometrial malignancy of the presence of endometrial cells on cervical cytology ranged between 13% and 17%. The presence of atypical endometrial cells on cervical smear was associated with endometrial malignancy in almost half the cases. The authors concluded that cervical cytology is of limited value in the diagnosis and management of post-menopausal endometrial disease.

Dijkhuizen et al. (2000) performed a meta-analysis to assess the accuracy of endometrial sampling devices in the detection of endometrial carcinoma and atypical hyperplasia. The authors searched the literature for studies published between 1966 and 1999 that compared the results of endometrial sampling with findings at D&C, hysteroscopy, and/or hysterectomy. They found 39 studies that included 7,914 women. For each study, the number of patients in which endometrial sampling failed, as well as the sensitivity and specificity for the detection of endometrial carcinoma and atypical hyperplasia, was calculated. The detection rate for endometrial carcinoma was higher in post-menopausal women compared with pre-menopausal women. In both post-menopausal and pre-menopausal women, the Pipelle was the best device, with detection rates of 99.6% and 91%, respectively. For the detection of atypical hyperplasia, there was only one study that reported explicitly on post-menopausal women, thereby hampering the possibility of subgroup analysis. Again, the Pipelle was the most sensitive technique, with a sensitivity of 81%. The specificity of all devices was greater than 98%. The authors concluded that endometrial biopsy with the Pipelle is superior to other endometrial techniques in the detection of endometrial carcinoma and atypical hyperplasia. The accuracy of the Pipelle is higher in post-menopausal women compared with pre-menopausal women.

In a case series on the use of the Tao Brush for endometrial biopsy, Wu et al. (2003) reported that the sensitivity and specificity in identifying endometrial cancer were 100% and 96%; however, diagnosis relied mainly on histologic evaluation of hematoxylin and eosin-stained tissue sections, and assessment of specimen adequacy was important when interpreting Tao Brush biopsies.

In an unblinded randomized trial, Critchley et al. (2004) compared three outpatient methods of endometrial evaluation in terms of performance, patient acceptability, and cost-effectiveness. Women referred for investigation and management of abnormal bleeding between January 1999 and May 2001 were evaluated using blind biopsy alone, hysteroscopy with biopsy, ultrasound evaluation including transvaginal ultrasound, and, in the low-risk group, the option of no investigation. Within this design, two devices for obtaining endometrial biopsy were compared: the Pipelle sampler and the Tao Brush. Minor adverse events (e.g., shock, patient distress) did not occur for ultrasound but occurred in 16% and 10% of women for hysteroscopy and biopsy procedures, respectively. Pipelle biopsy provided an acceptable endometrial sample for 79% of moderate-risk women, but only 43% of high-risk women. The Tao Brush gave similar performance in moderate-risk women (77%) but was more successful than the Pipelle sampler in post-menopausal (high-risk) women (72%).

To determine the performance characteristics of endometrial cytology for the detection of malignancy and atypical hyperplasia using liquid-based cytology specimens collected with the Tao Brush sampler, Kipp et al. (2008) obtained brushings of the endometrial cavity from 139 hysterectomy specimens before routine histopathologic evaluation. Cytology specimens were fixed in PreservCyt and processed using ThinPrep technology. Cytology diagnoses were classified as non-diagnostic, negative, atypical, or positive for malignancy. Histopathologic findings were used as the gold standard for determining the performance characteristics of cytology. Histopathologic results from the 139 patients included 81 (58%) endometrial cancers, 7 (5%) complex hyperplasia with atypia, 2 (1%) complex hyperplasia without atypia, and 49 (35%) patients with benign histology. The number of specimens diagnosed cytologically as positive, atypical, negative, or non-diagnostic was 60 (43%), 40 (29%), 37 (27%), and 2 (1%), respectively. The overall sensitivity and specificity of cytology for detecting endometrial cancer and atypical hyperplasia were 95% and 66% when atypical cytology specimens were considered positive. The authors concluded that direct endometrial sampling by liquid-based endometrial cytology collected with the Tao Brush sampler produces specimens that contain cellular material that may be identified as endometrial cancer or atypical hyperplasia; however, both atypical and positive cytology diagnoses are indicators for triage to more specific methods of diagnosis.

Williams et al. (2008) evaluated factors affecting the adequacy of Pipelle and Tao Brush endometrial sampling. Women referred to an outpatient clinic for assessment of abnormal vaginal bleeding (n = 200) were assigned to one of two risk groups: "high risk" for post-menopausal women and "moderate risk" for pre-menopausal women aged 40 years or older or with other risk factors. Women in each risk group had both Tao Brush and Pipelle biopsy and were then randomized to have either hysteroscopy and/or transvaginal ultrasound. Nulliparity was associated with failed insertion for both the Tao Brush and Pipelle (p < 0.001). Among post-menopausal women, inadequate samples were associated with the Pipelle (p < 0.001). Among pre-menopausal women with nulliparity, both the Tao Brush and Pipelle were associated with inadequate samples (p < 0.001). A significantly greater proportion of women preferred the Tao Brush to the Pipelle.

Outpatient endometrial biopsy has a high overall accuracy in diagnosing endometrial cancer when an adequate specimen is obtained. A positive test result is more accurate for ruling in disease than a negative test result is for ruling it out. Therefore, in cases of abnormal uterine bleeding where symptoms persist despite negative biopsy, further evaluation will be warranted (Clark et al., 2002). If the woman is post-menopausal and bleeding has not been persistent, a thin endometrial stripe in this setting is most consistent with atrophy and does not require further invasive studies. A thick endometrial stripe, persistent bleeding, or bleeding in a post- or peri-menopausal woman should be followed by additional endometrial sampling, such as hysteroscopy with curettage. In asymptomatic post-menopausal women, the decision to biopsy is also based upon a variety of factors, including cervical cytology showing endometrial cells or glandular abnormality, and risk factors for endometrial cancer, such as unopposed estrogen and tamoxifen use. In a completely asymptomatic post-menopausal woman with no risk factors and an endometrial stripe less than 5 mm, there is no need for biopsy. However, even one drop of blood in a post-menopausal woman not on hormone therapy constitutes a symptom and is an indication for biopsy.

Current evidence-based guidelines from leading medical professional organizations include no recommendation for endometrial or cervical cytology performed in conjunction with endometrial histology (Gynecor TruTest) in the diagnostic evaluation of abnormal uterine bleeding in women suspected of having endometrial hyperplasia or endometrial carcinoma. There is insufficient evidence to support this approach.

Endometrial surveillance is medically necessary in women with Lynch syndrome. Meyer et al. (2009) stated that about 2 to 5% of endometrial cancers may be due to an inherited susceptibility. Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC) syndrome, is an autosomal-dominant inherited cancer susceptibility syndrome. It is caused by a germline mutation in one of the DNA mismatch repair genes and accounts for the majority of inherited cases. Lynch syndrome is associated with early onset of cancer and the development of multiple cancer types, especially colon and endometrial cancer. The lifetime cumulative risk of endometrial cancer for women with Lynch syndrome is 40 to 60%, which equals or exceeds their risk of colorectal cancer. No current evidence suggests either a survival advantage or disadvantage to endometrial cancer that is associated with Lynch syndrome when these cases are compared with sporadic cases. A combination of family and personal medical history and tumor testing provides an efficient basis for diagnosing Lynch syndrome in women with endometrial cancer. The authors noted that current gynecologic cancer screening guidelines for women with Lynch syndrome include annual endometrial sampling and transvaginal ultrasonography (TVUS) beginning at age 30 to 35 years (Lindor et al., 2006).

Gerritzen et al. (2009) evaluated the effectiveness of gynecological surveillance with regard to endometrial and ovarian carcinoma. Included were women from families that fulfilled the revised Amsterdam criteria for HNPCC or who showed a proven mutation in one of the mismatch repair genes. Annual gynecological surveillance was performed (TVUS and cancer antigen 125 [CA-125] assessment). A total of 285 surveillance visits (100 women) were performed. Among these, in 64 visits, routine endometrial samplings were carried out: 3 atypical hyperplasia and 1 endometrial carcinoma were diagnosed. This was significantly more than the atypical hyperplasia and 2 endometrial carcinomas that were detected after 28 samples performed because of abnormal surveillance results in 221 visits. There were no interval carcinomas. One invasive ovarian carcinoma stage IIIC was diagnosed at ovarian surveillance. Endometrial surveillance with routine endometrial sampling in women with HNPCC is more efficient in diagnosing endometrial pre-malignancies than TVUS only. Ovarian surveillance is not capable of diagnosing early-stage ovarian carcinoma. Prophylactic hysterectomy in HNPCC should be restricted to women in whom abdominal surgery for other reasons is performed and to those with particularly increased risk, such as MSH6 mutation carriers and/or women with multiple relatives with endometrial carcinoma.

The American Cancer Society (2011) recommends that all women should be informed about the risks and symptoms of endometrial cancer and strongly encouraged to report any unexpected bleeding or spotting to their doctors. For women with or at high risk for hereditary non-polyposis colon cancer (HNPCC, Lynch syndrome), annual screening should be offered for endometrial cancer with endometrial biopsy beginning at age 35.

Robison and colleagues (2011) noted that sentinel lymph node (SLN) dissections have been shown to be sensitive for the evaluation of nodal basins for metastatic disease and are associated with decreased short-term and long-term morbidity when compared with complete lymph node dissection. There has been increasing interest in the use of SLN technology in gynecologic cancers. These investigators evaluated the current evidence-based literature for the use of SLN dissections in gynecologic malignancies. Recent literature continues to support the safety and feasibility of SLN biopsy for early-stage vulvar cancer, with negative predictive value approaching 100% and low false-negative rates. Alternatively, for endometrial cancer, most studies have reported low false-negative rates, with variable sensitivities, and have reported low detection rates of the sentinel node. Studies examining the utility of SLN biopsy in early-stage cervical cancer remain promising, with detection rates, sensitivities, and false-negative rates greater than 90% for stage 1B1 tumors. The authors concluded that SLN dissections have been shown to be effective and safe in certain select vulvar cancer patients and can be considered an alternative surgical approach for these patients. For endometrial and cervical cancer, SLN dissection continues to have encouraging results; however, it needs further investigation.

Kang and associates (2011) stated that the validity of the SLN biopsy for the assessment of nodal status in patients with endometrial cancer is unclear. These investigators evaluated the diagnostic performance of this procedure. They searched the PubMed and Embase databases for studies published before June 1, 2011. Eligible studies had a sample size of at least 10 patients and reported the detection rate and/or sensitivity of the SLN biopsy. These researchers identified 26 eligible studies, which included 1,101 SLN procedures. The overall weighted mean number of harvested SLNs was 2.6. The detection rate and the sensitivity were 78% (95% confidence interval [CI]: 73% to 84%) and 93% (95% CI: 87% to 100%), respectively. Significant between-study heterogeneity was observed in the analysis of the detection rate (I-squared statistic, 80%). The use of peri-cervical injection was correlated with an increase in the detection rate (p = 0.031). The hysteroscopic injection technique was associated with a decrease in the detection rate (p = 0.045), and the sub-serosal injection technique was associated with a decrease in sensitivity (p = 0.049) if they were not combined with other injection techniques. For the detection rate, significant small-study effects were noted (p < 0.001). The authors concluded that although SLN biopsy has shown good diagnostic performance in endometrial cancer, such performance should be interpreted with caution because of significant small study effects. They stated that current evidence is not yet sufficient to establish the true performance of SLN biopsy in endometrial cancer.

Godoy and colleagues (2013) evaluated the accuracy of sonographic endometrial thickness and hysteroscopic characteristics in predicting malignancy in post-menopausal women undergoing surgical resection of endometrial polyps. A total of 521 post-menopausal women undergoing hysteroscopic resection of endometrial polyps between January 1998 and December 2008 were studied. For each value of sonographic endometrial thickness and polyp size on hysteroscopy, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated in relation to the histologic diagnosis of malignancy. The best values of sensitivity and specificity for the diagnosis of malignancy were determined by the Receiver Operating Characteristic (ROC) curve. Histologic diagnosis identified the presence of pre-malignancy or malignancy in 4.1% of cases. Sonographic measurement revealed a greater endometrial thickness in cases of malignant polyps when compared to benign and pre-malignant polyps. On surgical hysteroscopy, malignant endometrial polyps were also larger. An endometrial thickness of 13 mm showed a sensitivity of 69.6%, specificity of 68.5%, PPV of 9.3%, and NPV of 98% in predicting malignancy in endometrial polyps. Polyp measurement by hysteroscopy showed that for polyps 30 mm in size, the sensitivity was 47.8%, specificity was 66.1%, PPV was 6.1%, and NPV was 96.5% for predicting cancer. The authors concluded that sonographic endometrial thickness showed a higher level of accuracy than hysteroscopic measurement in predicting malignancy in endometrial polyps. Despite this, both techniques showed low accuracy for predicting malignancy in endometrial polyps in post-menopausal women. In suspected cases, histologic evaluation is necessary to exclude malignancy.

Cavkaytar et al. (2014) evaluated the role of sonographic endometrial thickness and hysteroscopic polyp size in predicting pre-malignant and malignant polyps in post-menopausal women. A total of 328 post-menopausal women with abnormal uterine bleeding and thickened endometrium who underwent operative hysteroscopy due to the detection of endometrial polyps were included in this retrospective study. Pre-operative endometrial thickness measured by transvaginal ultrasonography and polyp size on hysteroscopy were noted. Hysteroscopic resection with histology was performed for endometrial polyps. Endometrial thickness and polyp size were evaluated based on the final diagnosis established by histologic examination. Receiver operator characteristic curves were calculated to assess the sensitivity, specificity, PPV, NPV, and diagnostic accuracy of endometrial thickness and polyp size for detecting pre-malignant and malignant polyps. Pre-malignant and malignant polyps were identified in 26 (7.9%) of cases. Sonographic measurement showed a greater endometrial thickness in cases of pre-malignant and malignant polyps when compared to benign polyps. On surgical hysteroscopy, pre-malignant and malignant polyps were also larger. Endometrial thickness demonstrated a sensitivity of 53.8%, specificity of 85.8%, PPV of 24.6%, and NPV of 95.6% at a cut-off limit of 11.5 mm, with diagnostic accuracy of 83.2%. Polyp size had a diagnostic accuracy of 94.8%, with a sensitivity of 92.3%, specificity of 95.0%, PPV of 61.5%, and NPV of 99.3% at a cut-off point of 19.5 mm. The authors concluded that endometrial thickness measured by transvaginal ultrasonography is not sufficient in predicting pre-malignant and malignant endometrial polyps in post-menopausal women with abnormal uterine bleeding and thickened endometrium. Polyp size on hysteroscopy is a more accurate parameter because of better sensitivity and specificity. However, while a polyp size greater than or equal to 19.5 mm seems to have great accuracy for predicting pre-malignancy and malignancy, histologic evaluation is still necessary to exclude pre-malignant and malignant polyps.

Ansari and colleagues (2013) stated that sentinel lymph node biopsy is a fairly new approach for staging gynecological malignancies. In the current study, these researchers comprehensively reviewed the available reports on sentinel node biopsy of endometrial carcinoma (EC). They searched Medline, SCOPUS, ISI Web of Knowledge, Science Direct, Springer, OVID SP, and Google Scholar with the following search terms: "endometrium or endometrial or uterine or uterus and sentinel." The outcomes of interest were detection rate and sensitivity. Overall, a total of 35 studies had enough information for false-negative rate evaluation and 51 studies (including the sub-groups of individual studies) for detection rate evaluation (2,071 patients overall). The pooled detection rate was 77.8% (95% CI: 73.5 to 81.5%) and pooled sensitivity was 89% (95% CI: 83 to 93%). Cervical injection, as well as using both blue dye and radiotracer, resulted in higher detection rates and sensitivity. New techniques such as fluorescent dye injection and robotic-assisted surgery showed high detection rates and sensitivity. The authors concluded that sentinel node mapping is feasible in EC. Using both blue dye and radiotracer and cervical injection of the mapping material can optimize the sensitivity and detection rate of this technique. Moreover, they stated that larger studies are still needed to evaluate the false-negative rate and the factors influencing sensitivity before considering this method safe.

Circular RNAs Expression for Grade-3 Endometrial Cancer

Ye and colleagues (2019) noted that circular RNAs (circRNAs), a class of newly discovered endogenous non-coding RNAs, have shown large capabilities in gene regulation. Patients with the grade-3 endometrial cancer (EC) have a generally poor prognosis, and the specific role of circRNAs in the grade-3 EC remains unclear. These investigators examined the roles of circRNAs in the grade-3 EC. They screened the expression profiles of circRNAs taken from 2 women with the grade-3 EC and adjacent non-cancerous endometrial tissue using circRNAs sequencing. Bioinformatic analyses were applied to study these differentially expressed circRNAs. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) of 6 dysregulated circRNAs was performed to validate the sequencing results. Bioinformatic analyses, including the negative correlation network analyses of circRNAs-microRNAs (miRNAs)-messenger RNAs (mRNAs) and the Cytoscape, were used to delineate the interaction of circRNAs/miRNAs of the entire network. Data of circRNA sequencing showed a significant change in 75,928 unique circRNAs (p < 0.05). The up-regulated hsa_circ_0039569 and hsa_circ_0001610 and down-regulated hsa_circ_0000437, hsa_circ_0001776, and hsa_circ_0009043 were validated by qRT-PCR analysis. Using bioinformatical methods, these researchers found that hsa_circ_0039569 had the MRE of hsa-miR-542-3p and hsa-let-7c-5p. Hsa-miR-542-3p and hsa-let-7c-5p were down-regulated in the grade-3 EC validated by qRT-PCR analysis. In the clinicopathological parameters, the expression level of hsa_circ_0039569 was significantly correlated with tumor differentiation (p = 0.001). The authors concluded that this was the 1st study, which demonstrated that there were a lot of differences between the tissue of the grade-3 EC and adjacent non-cancerous endometrial in circRNA expression and may offer novel molecular candidates for diagnosis and clinical treatment of the grade-3 EC.

Circulating Adiponectin, Leptin, and Adiponectin-Leptin Ratio

In a systematic review and meta-analysis, Zeng and co-workers (2015) evaluated the association between serum adiponectin (APN) concentrations and the risk of endometrial cancer. They searched PubMed, Embase, the Chinese Biomedical Literature Database, and the Science Citation Index (ISI Web of Science) for studies examining the relationship between blood APN concentrations and endometrial cancer risk. Data from studies that met the inclusion criteria were systematically reviewed, and pooled analyses were performed according to the guidelines of the Meta-Analysis of Observational Studies in Epidemiology and PRISMA. A total of eight case-control studies (including 1,257 endometrial cancer patients and 2,008 controls) and four nested case-control studies (including 659 endometrial cancer patients and 1,398 controls) were included. The researchers found that serum APN levels were inversely correlated with the risk of endometrial cancer development after pooling the case-control studies (odds ratios [OR] = 0.50, 95% CI: 0.39 to 0.60; p < 0.001). However, the meta-analysis of nested case-control studies did not support a broad linkage between serum APN levels and endometrial cancer, although a correlation may exist in the subgroup of post-menopausal women (OR = 0.81, 95% CI: 0.65 to 1.00; p = 0.060), especially in post-menopausal women without current hormone replacement therapy (OR = 0.62, 95% CI: 0.44 to 0.86; p = 0.004). The authors concluded that the meta-analysis of currently available clinical evidence supported the association between high serum APN concentration and reduced risk of endometrial cancer development, particularly in post-menopausal women without current hormone replacement therapy. However, they stated that additional studies with prospective designs are needed to validate this linkage.

Gong and associates (2015) performed a meta-analysis of epidemiologic studies to investigate the associations between circulating APN, leptin (LT), and the APN-LT (A/L) ratio and endometrial cancer risk. Relevant manuscripts were identified by searching PubMed and ISI Web of Science databases, as well as by manually searching the references cited in retrieved manuscripts. Random-effects models were used to estimate summary odds ratios (SOR) and 95% confidence intervals (CIs) for the aforementioned associations. A total of 14 manuscripts with 13 studies (5 nested case-control and 8 case-control studies) cumulatively involving 1,963 endometrial cancer cases and 3,503 non-cases were included in the analyses. Overall, comparing individuals with circulating concentrations of APN, LT, and A/L ratio in the top tertile with those in the bottom tertile yielded SORs of 0.47 (95% CI: 0.34 to 0.65; I² = 63.7%; n = 13), 2.19 (95% CI: 1.44 to 3.31; I² = 64.2%; n = 7), and 0.45 (95% CI: 0.24 to 0.86; I² = 90.1%; n = 5), respectively. Notably, there was an 18% reduction in risk for each 5 μg/ml increment in circulating APN concentrations (SOR = 0.82; 95% CI: 0.74 to 0.90; I² = 49%; n = 8). Stratifying by study characteristics and whether these studies considered or adjusted for potential confounders, the findings were robust in the analyses of circulating APN and LT. No evidence of publication bias was detected. The authors concluded that the findings from this meta-analysis suggested that increased circulating APN and A/L ratio or decreased LT concentrations were associated with a reduced risk of endometrial cancer. They stated that further prospective studies are needed to confirm these findings.

Li and colleagues (2016) noted that previous epidemiological studies have presented conflicting results regarding associations between circulating APN levels and the risk of endometrial cancer. In a meta-analysis, these researchers examined the association between these factors. Multiple electronic sources, including PubMed, SpringerLink, and Google Scholar databases, were searched to identify relevant studies for the present meta-analysis. All selected studies examined the correlation between circulating APN levels and endometrial cancer. The standardized mean difference (SMD) and 95% CIs were estimated and pooled using meta-analysis methods. A total of 18 case-control studies met the inclusion criteria, including 5,692 participants and 2,337 cases of endometrial cancer. The SMD of the pooled analysis (95% CI) was -1.96 (-2.60 to -1.31), p = 0.000. When comparing cancer grades, the APN values were not significantly different between the grades of endometrial cancer [G1 versus G3, 1.02 (-0.68 to 2.72), p > 0.05; G1 versus G2, 0.34 (-0.86 to 1.54), p > 0.05]. However, there was a significant association between high APN levels and post-menopausal endometrial cancer cases, with an SMD (95% CI) of -2.27 (-4.36 to -0.18) and p < 0.05; no association was observed in pre-menopausal endometrial cancer cases, with an SMD (95% CI) of -1.52 (-3.49 to 0.45) and p > 0.05. The low circulating APN level increased the risk of endometrial cancer, whereas the high APN level decreased this risk in post-menopausal women. The authors concluded that circulating APN as a simple biomarker may be a promising tool for the prevention, early diagnosis, and disease monitoring of endometrial cancer.

Circulating and Endometrial Tissue MicroRNA Markers for the Diagnosis and Prognosis of Endometrial Cancer

Oropeza-de Lara et al. (2023) noted that in developed countries, endometrial cancer (EC) is one of the most common neoplasms of the female reproductive system. MicroRNAs (miRs) are a class of single-stranded non-coding RNA molecules, ranging from 19 to 25 nucleotides in length, that bind to target mRNA to regulate post-transcriptional gene expression. Although there is extensive research focused on identifying miRs with diagnostic, prognostic, or treatment response capabilities in EC, these studies vary in terms of experimental methodology, types of samples used, selection criteria, and results obtained. Consequently, there is a large amount of heterogeneous information that complicates the identification of potential miR biomarkers. The researchers examined the available evidence on miRs that have been shown to be the most suitable potential markers for EC. They conducted a search on PubMed and Google Scholar without date restrictions or filters. The investigators described 138 miRs with potential diagnostic, prognostic, or treatment response capabilities in EC; notably, seven diagnostic panels demonstrated higher sensitivity and specificity for the diagnosis of EC compared to individual miRs. They further identified miRs that were up- or down-regulated depending on the FIGO stage, precursor lesions, and staging following surgery, providing insight into which miRs are expressed chronologically based on disease stage and/or modulated according to tumor grade as assessed by histopathological evaluation.

The authors emphasized that despite the substantial amount of existing data on miRs and EC, it is currently not feasible to use miRs in the diagnostic approach for EC because the full characterization required to employ them as a tool in the medical field is not yet fully established. For instance, there are no well-defined expression cut-off points associated with the disease or its features or progression stages. Additionally, some drawbacks identified during the literature review include that most studies have been retrospective and conducted on small, heterogeneous populations, and there is significant variability in the experimental methodology and the type and quality of samples evaluated in each study. As a result, it is currently impossible to establish a consensus on their clinical utility. However, the information integrated into this review may serve as a foundation for conducting clinical trials using either one panel or individual miRs to determine the optimal method for miR extraction (based on the biological sample used), establish clinically significant cut-off expression values (diagnostic, prognostic, or treatment-related), and develop appropriate methods for data collection and integration with recent molecular classifications of EC. Furthermore, it is highly desirable to incorporate the miRs that have demonstrated clinical utility to stratify patients according to treatment or adjuvant treatment modalities, thereby attempting to unify the information generated from these miRs with the classifications used by validated medical guidelines.

Circulating YKL-40

Cheng and colleagues (2014) stated that i the past 10 years, several studies have suggested a possible link between circulating YKL-40 levels and EC, but have arrived at inconsistent results. These researchers performed a meta-analysis and disclosed a more comprehensive evaluation of the sensitivity, specificity, and diagnostic accuracy of YKL-40 in EC. The authors systematically searched PubMed, Embase, Web of Science, Science Direct, SpringerLink, EBSCO, Wanfang, and Chinese National Knowledge Infrastructure databases for studies that evaluated the diagnostic value of YKL-40 in endometrial cancer. The STATA software 12.0 and Meta-Disc software were used to test the heterogeneity and to evaluate the overall test performance. A total of 7 studies including 234 EC cases and 300 controls were included in the meta-analysis. The summary estimates of YKL-40 for EC diagnosis indicated a moderately high diagnostic accuracy for circulating YKL-40, with a sensitivity of 0.74, a specificity of 0.87, a positive likelihood ratio (PLR) of 5.74, a negative likelihood ratio (NLR) of 0.30, a diagnostic odds ratio (DOR) of 19.14, and an area under the ROC curve (AUC) of 0.80. The authors concluded that circulating YKL-40 could be promising and meaningful in the diagnosis of EC.

National Comprehensive Cancer Network’s clinical practice guideline on “Uterine neoplasms” (Version 3.2026) does not mention circulating YKL-40 for the diagnosis of EC.

DNA Methylation for Diagnosis of Sporadic Endometrial Cancer

Fan and colleagues (2017) stated that although an increasing number of methylated genes have been identified as biomarkers for endometrial cancer, the results have been inconsistent. These investigators performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of methylated genes as markers for sporadic endometrial cancer. A total of 22 studies, including 1,930 participants (sporadic endometrial cancer patients and normal individuals), met the eligibility criteria. The pooled sensitivity and specificity were found to be 0.93 (95% confidence interval: 0.91 to 0.94) and 0.48 (95% CI: 0.46 to 0.50), respectively. The area under the summary receiver operating characteristic curve was 0.8834. The presence of DNA methylation was significantly associated with lymph node metastasis of endometrial cancer (pooled odds ratio [OR]: 0.28, 95% CI: 0.15 to 0.52, p < 0.001). These investigators systematically searched the relevant literature using the PubMed and Web of Science databases up to April 2017. Diagnostic accuracy variables were pooled and analyzed using Meta-DiSc software. Sensitivity analysis and publication bias were evaluated using Review Manager. The authors concluded that the findings of this meta-analysis suggested that the detection of DNA methylation is associated with lymph node metastasis, with high sensitivity but relatively low specificity for the diagnosis of sporadic endometrial cancer. Moreover, they stated that further meta-analyses need to be conducted to address the use of accurate methylated targets and suitable detection techniques, while more prospective studies utilizing consistent and standardized methodologies are urgently needed to resolve these issues.

The authors acknowledged several drawbacks in this study. First, selection bias might have occurred due to the enrichment of studies reporting positive results, and the relatively small sample sizes in some of the selected literature may also have led to bias. Furthermore, the included studies were mostly from East Asia, which may limit the universal applicability of the conclusions. The use of different methylation-specific polymerase chain reaction primers and/or equipment, along with the lack of a well-accepted methylated gene in sporadic endometrial cancer, might also have been potential sources of bias.

van den Helder and colleagues (2020) stated that DNA methylation testing for endometrial cancer detection in minimally invasive specimens is a promising tool to improve screening and diagnostic procedures. Available literature was systematically reviewed to examine the potential of this approach and to define methylation markers deserving further development. These investigators conducted a systematic search up to March 31, 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 15 methylation markers with an area under the curve (AUC) of greater than or equal to 0.80 for endometrial cancer detection in cytological specimens were selected from nine studies. The authors concluded that the detection of methylation markers in cytological samples indicated the feasibility of minimally invasive testing methods, potentially guiding the diagnosis and detection of endometrial cancer in high-risk women and in cancer screening programs.

The NCCN Uterine Neoplasms guideline (3.2026) provides no recommendation for methylation-based diagnosis or screening and references methylation only as MLH1 promoter testing to characterize already-diagnosed MMR-deficient tumors.

Evidence evaluating DNA methylation testing for endometrial cancer suggests that methylation-based assays obtained from cervical, cervicovaginal, urinary, and other minimally invasive samples can identify endometrial cancer with generally high reported diagnostic accuracy; however, the evidence remains limited by heterogeneous gene panels, non-standardized testing methodologies, and study populations that largely consist of symptomatic or referred women rather than average-risk screening populations (den Helder et al., 2020; Ran et al., 2025). Prospective and multicenter cohort studies have reported favorable sensitivity, specificity, and area-under-the-curve estimates for several methylation assays, suggesting potential utility as a noninvasive adjunctive diagnostic approach (Lee et al., 2025; Cai et al., 2026; Illah et al., 2024; Ma et al., 2024; Wever et al., 2023). Nevertheless, evidence remains insufficient to establish clinical validity and utility for routine diagnosis or population-based screening because of study heterogeneity, limited external validation, reduced performance for premalignant lesions such as endometrial intraepithelial neoplasia/atypical hyperplasia, and a lack of standardized or widely adopted assays (Yu et al., 2026; Ran et al., 2025). Furthermore, major clinical practice guidelines do not currently recommend DNA methylation testing for the diagnosis or screening of endometrial cancer, and no clear consensus exists regarding its role in clinical management (NCCN, 2026).

DNA Methylation for Screening of Endometrial Cancer

Wever et al. (2023) noted that the incidence of endometrial cancer (EC) is increasing, and current diagnostic methods often require invasive biopsies. DNA methylation marker analysis of minimally and non-invasive sample types could provide a convenient alternative for determining cancer risk. The researchers compared the performance of DNA methylation markers in detecting endometrial cancer in urine, cervico-vaginal self-samples, and clinician-taken cervical scrapes. Paired samples were collected from 103 patients diagnosed with stage I to IV endometrial cancer, with urine and self-samples collected at home. All samples were tested for nine DNA methylation markers using quantitative methylation-specific PCR. Methylation levels in endometrial cancer patients were compared to unpaired samples from 317 healthy controls (HCs). Diagnostic performance was evaluated using uni-variable and multi-variable logistic regression analysis, followed by leave-one-out cross-validation. Each methylation marker exhibited significantly higher methylation levels in all sample types from endometrial cancer patients compared to HCs (p < 0.01). Optimal three-marker combinations demonstrated excellent diagnostic performance, with area under the ROC values of 0.95 (95% CI: 0.92 to 0.98), 0.94 (0.90 to 0.97), and 0.97 (0.96 to 0.99) for endometrial cancer detection in urine, self-samples, and scrapes, respectively. Sensitivities ranged from 89% to 93% at specificities of 90% to 92%. Virtually equal performances were obtained after cross-validation, and excellent diagnostic performance was maintained for stage I endometrial cancer detection. The authors concluded that the findings of this study demonstrated the value of methylation analysis in patient-friendly sample types for detecting endometrial cancer at all stages, indicating that this approach has great potential for screening patient populations at risk for endometrial cancer. Furthermore, they stated that following validation in additional cohorts, including individuals presenting with post-menopausal bleeding and asymptomatic women at risk for endometrial cancer, methylation testing could serve as a pre-selection method to inexpensively determine who needs to undergo invasive endometrial tissue sampling, facilitating timely diagnosis.

The authors acknowledged several drawbacks of this study. First, the distribution of histopathological subtypes included in this trial did not reflect natural prevalence, as most patients diagnosed with endometrial cancer were from tertiary care cancer centers treating high-grade cancers and rare histopathological subtypes. However, it is worth noting that early detection of high-grade non-endometrioid cancers is crucial due to their worse prognosis. Second, samples were not collected at the first clinical presentation but after a diagnosis of endometrial cancer was made based on a pipelle or hysteroscopic biopsy. This order would differ in clinical practice if home-based sampling were used. Sample collection after an endometrial biopsy might have facilitated the release of tumor DNA into the urine or vaginal fluid. Nevertheless, the influence of biopsy procedures on the presence of tumor DNA in self-collected specimens is likely limited, as the median time between biopsy and self-sampling was 37 days. In some excluded cases, the complete carcinoma was biopsied, with no or minimal residual cancer found during histopathological evaluation of the uterus. It is conceivable that DNA methylation testing will be even more accurate when used at the first clinical presentation. Third, this comparative study lacked access to paired samples from controls and did not include controls with post-menopausal bleeding symptoms or benign endometrial conditions. Although other studies have shown that most of the markers tested in this trial can discriminate between benign endometrial pathology and cancer, this was not validated in the current study.

Peng et al. (2023) stated that DNA methylation is a common epigenetic modification, and the current methods for DNA methylation detection include methylation-specific PCR, methylation-sensitive restriction endonuclease-PCR, and methylation-specific sequencing. DNA methylation plays a significant role in genomic and epigenomic studies, and combining DNA methylation with other epigenetic modifications, such as histone modifications, may enhance its effectiveness. Additionally, DNA methylation is crucial in disease development, and analyzing changes in individual DNA methylation patterns can provide personalized diagnostic and therapeutic solutions. Liquid biopsy techniques are also becoming well established in clinical practice and may offer new methods for early cancer screening. The researchers emphasized the importance of finding new screening methods that are easy to perform, minimally invasive, patient-friendly, and affordable. They noted that DNA methylation mechanisms are thought to play a significant role in cancer and have potential applications in the diagnosis and treatment of female tumors. The authors discussed early detection targets and screening methods for common female tumors, such as breast, ovarian, and cervical cancers, and highlighted advances in the study of DNA methylation in these tumors. However, this review did not address DNA methylation in endometrial cancer.

Zhao et al. (2024) examined the value of DNA (CDO1m/CELF4m) methylation detection in exfoliated cervical cells collected for screening endometrial cancer in pre-menopausal women with abnormal uterine bleeding. A total of 296 pre-menopausal women with abnormal uterine bleeding were admitted to the Department of Obstetrics and Gynecology at the Third Xiangya Hospital of Central South University from November 2021 to October 2022. Clinical characteristics, endometrial thickness measured by transvaginal ultrasound (TVUS), and serum CA125 levels were collected. Exfoliated cervical cells from the ThinPrep cytologic test were collected for DNA (CDO1m/CELF4m) methylation testing, and endometrial tissue was collected under hysteroscopy for pathological diagnosis as the gold standard. A univariate logistic regression model was used to analyze risk factors for endometrial cancer. The ROC curve and area under the curve (AUC) were employed to measure the diagnostic effectiveness of DNA methylation detection in screening for endometrial cancer in women with abnormal uterine bleeding. Univariate logistic regression analysis revealed that age, BMI of 25 kg/m² or higher, endometrial thickness of 11 mm or greater, CDO1 methylation (CDO1mΔCt of 8.4 or less), CELF4 methylation (CELF4mΔCt of 8.8 or less), and dual gene methylation (CDO1mΔCt of 8.4 or less; or CELF4mΔCt of 8.8 or less) were independent risk factors for endometrial cancer in this population. The odds ratios (OR) were 0.87 (95% CI: 0.80 to 0.95), 4.76 (1.89 to 11.96), 8.41 (3.13 to 22.59), 64.49 (20.46 to 203.33), 12.79 (4.91 to 33.30), and 42.53 (11.90 to 152.04), respectively. Among these indicators, dual gene methylation exhibited the highest sensitivity and specificity for endometrial cancer screening (85.7% and 87.6%). Moreover, dual gene methylation combined with BMI or endometrial thickness could further enhance the screening efficiency for endometrial cancer in women with abnormal uterine bleeding. The authors concluded that in pre-menopausal women with abnormal uterine bleeding, the clinical effectiveness of DNA (CDO1m/CELF4m) methylation detection in exfoliated cervical cells for endometrial cancer screening was superior to that of other non-invasive clinical indicators. Furthermore, dual gene methylation combined with BMI or endometrial thickness was identified as a good predictor for endometrial cancer screening.

Kwinten et al. (2024) stated that in the past decade, technical innovations have led to the development of several minimally invasive diagnostic cancer tools. For women at high risk of developing ovarian or endometrial cancer due to hereditary cancer syndromes, there is an urgent need for minimally invasive and patient-friendly methods to detect these cancers at an early stage. The investigators conducted a systematic search of studies utilizing DNA methylation or mutation analysis, microbiome, or proteomics performed on cervico-vaginal specimens (smear, swab, or tampon) intended for detecting ovarian and endometrial cancer, published until January 2024. The included studies (n = 36) exhibited high heterogeneity in terms of biomarkers used and outcomes, with only a few studies reporting on the detection of biomarkers in high-risk subgroups. The authors concluded that based on the findings of this review, DNA methylation techniques appeared to be the most promising for detecting ovarian and endometrial cancer at early stages in the general population. They stated that future validation of cervico-vaginal DNA methylation techniques is necessary to determine if this approach could be beneficial in hereditary high-risk subgroups.

Furthermore, the National Comprehensive Cancer Network’s clinical practice guideline on “Uterine Neoplasms” (Version 3.2026) does not mention DNA methylation as a management option.

FTO rs9939609 Gene Polymorphism Testing

Huang and colleagues (2017) noted that obesity is a risk factor of cancer. Several genes have been found to play an important role in the etiology of obesity and tumourigenesis. Recent studies suggested that rs9939609 polymorphism might be significantly associated with cancer risk, while the results of some other studies were controversial. In a meta-analysis, these investigators examined the association between FTO gene polymorphism (rs9939609) and cancer risk. Databases with time limitation from January 1984 to April 2015 were searched. The pooled OR with 95% CI was calculated to assess the associations, and subgroup meta-analyses were performed according to the type of cancer and ethnicity of the study populations. Overall, the significant association between rs9939609 polymorphism and cancer risk was found in homozygote model and recessive model. As to subgroup classified by cancer type, there was significant association in endometrial cancer and pancreatic cancer, while no statistical significance was detected in other kind of cancers. Besides, in the subgroup analysis of ethnicity, these results indicated that rs9939609 polymorphism was significantly associated with cancer risk in Asians. The rs9939609 polymorphism may be involved the susceptibility of endometrial cancer and pancreatic cancer, especially in Asian populations. The authors concluded that rs9939609 may be a potential biomarker in early diagnosis or gene therapy target of endometrial cancer and pancreatic cancer.

HSD17B1 rs605059 Gene Polymorphism Testing

In a systemic review and meta-analysis, Mu and associates (2015) evaluated the HSD17B1 gene polymorphisms in the risks of endometrial cancer, endometriosis and uterine leiomyoma. A comprehensive electronic search was conducted in PubMed, Medline (Ovid), Embase, Weipu, Wanfang and CNKI. The pooled ORs were performed using the Revman 5.2 software. A total of 8 case-control studies were included: 3 were about endometrial cancer, 4 were about endometriosis and 1 was about uterine leiomyoma. The result showed no significant association between HSD17B1 rs605059 gene polymorphisms and risks of endometrial cancer (AA versus AG+GG: OR = 1.11, 95% CI: 0.94 to 1.32; AA+AG versus GG: OR = 1.79, 95% CI: 0.42 to 7.52; AG versus AA+GG: OR = 0.87, 95% CI :0.76 to 1.00; AA versus GG: OR = 1.43, 95% CI: 0.62 to 3.30; A versus G: OR = 1.00, 95 % CI: 0.91 to 1.11) or endometriosis (AA versus AG+GG: OR = 0.99, 95% CI: 0.75 to 1.32; AA+AG versus GG: OR = 1.73, 95% CI: 0.92 to 3.25; AG versus AA+GG: OR = 1.24, 95% CI: 1.00 to 1.53; AA versus GG: OR = 1.54, 95% CI: 0.79 to 2.97; A versus G: OR = 1.23, 95% CI: 0.90 to 1.68). No association was found in a subgroup analysis based on Asian ethnicity for endometriosis. The authors concluded that the findings of this meta-analysis suggested that HSD17B1 rs605059 polymorphisms were not associated with the risks of endometrial cancer and endometriosis. They stated that further studies are needed to validate the conclusion and clarify the relationship between HSD17B1 rs605059 polymorphisms and the risk of uterine leiomyoma.

Immunohistochemistry for Protein Phosphatase and Tensin Homolog (PTEN) for Differential Diagnosis of Benign and Pre-Malignant Endometrial Hyperplasia

Raffone and associates (2019) noted that endometrial hyperplasia (EH) may be either a benign proliferation or a pre-malignant lesion. To differentiate between these two conditions, two possible histologic classifications could be used: the World Health Organization (WHO) classification and the EIN classification. The 2017 European Society of Gynecological Oncology guidelines recommend the use of immunohistochemistry for tumor suppressor protein phosphatase and tensin homolog (PTEN) to improve the differential diagnosis. Nonetheless, its diagnostic accuracy has never been defined. These researchers examined the diagnostic accuracy of PTEN immunohistochemistry in the differential diagnosis between benign and pre-malignant EH. They searched electronic databases from their inception to May 2018 for studies assessing immunohistochemical expression of PTEN in EH specimens. PTEN status ("loss" or "presence") was the index test, while histological diagnosis ("pre-cancer" or "benign") served as the reference standard. Sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) on summary receiver operating characteristic (SROC) curves were calculated (95% CI), with a subgroup analysis based on the histologic classification adopted (WHO versus EIN). A total of 27 observational studies with 1,736 cases of EH were included. Pooled estimates showed low diagnostic accuracy: sensitivity 54% (95% CI: 50% to 59%), specificity 66% (63% to 69%), PLR 1.55 (1.29 to 1.87), NLR 0.72 (0.62 to 0.83), DOR 3.56 (2.02 to 6.28), and AUC 0.657. When comparing the WHO subgroup with the EIN subgroup, higher accuracy (AUC 0.694 versus 0.621) and higher heterogeneity in all analyses were observed. The authors concluded that immunohistochemistry for PTEN showed low diagnostic usefulness in the differential diagnosis between benign and pre-malignant EH. They stated that in the absence of further evidence, the recommendation regarding its use should be reconsidered, and further studies are needed to clarify the prognostic value of PTEN immunohistochemistry in EH, particularly concerning the progression to cancer.

Travaglino and colleagues (2019) stated that guidelines recommend PTEN immunohistochemistry for differentiating between benign EH (BEH) and atypical EH (AEH) / EIN. However, it remains unclear when PTEN expression should be defined as “lost” and thus suggestive of AEH / EIN. In a systematic review and meta-analysis, these investigators determined the optimal immunohistochemical criteria to define PTEN loss in EH. They searched electronic databases for studies assessing immunohistochemical expression of PTEN in both BEH and AEH / EIN specimens. PTEN status (“loss” or “presence”) was the index test, while histological diagnosis (“AEH / EIN” or “BEH”) served as the reference standard. Accuracy was quantified based on the AUC on SROC curves for several different thresholds of PTEN expression. A total of 18 studies with 1,362 cases of hyperplasia were included; six different criteria to define PTEN loss were assessed. Low diagnostic accuracy was found for complete loss of expression (AUC = 0.71), presence of any null gland (AUC = 0.63), positive cells less than 10% (AUC = 0.64), positive cells less than 50% (AUC = 0.71), and moderate-to-null intensity (AUC = 0.64). Barely moderate diagnostic accuracy was only found for the subjective criterion “weak-to-null intensity” (AUC = 0.78). The authors concluded that the clinical usefulness of PTEN immunohistochemistry in this field should be further examined.

Measurement of Blood Anti-Mullerian Hormone Level and Risk of Endometrial Cancer

Verdiesen and colleagues (2020) stated that experimental research suggested that anti-Mullerian hormone (AMH) inhibits tumor growth. Conversely, epidemiological studies indicated that higher AMH concentrations may increase breast cancer risk, while associations with other cancers are inconsistent. In a systematic review, these researchers evaluated current epidemiological evidence on AMH levels in relation to different cancer types. They conducted a systematic search of PubMed and Embase for publications on circulating AMH in relation to cancer. The methodological quality of the articles was examined using the Study Quality Assessment Tools of the National Heart, Lung, and Blood Institute. The investigators included 12 articles covering breast, ovarian, and endometrial cancer, lymphomas, non-gynecological cancers, childhood cancer, and prostate cancer; five studies measured AMH prior to cancer diagnosis, while the other studies measured AMH after diagnosis but before treatment. Higher pre-diagnosis AMH levels were associated with an increased risk of breast cancer. Associations with other types of cancer remained inconclusive, although analyses stratified by age suggested an increased risk of ovarian and endometrial cancer in younger women. Pre-treatment AMH levels were lower in women diagnosed with various types of cancer compared to AMH levels in healthy women. However, the investigators considered most of the studies that established pre-treatment AMH levels to be of poor methodological quality, primarily due to inadequate correction for age at measurement and other important confounders, leading them to refrain from drawing definitive conclusions based on these findings. The authors concluded that future studies involving young subjects are needed to examine if and how AMH affects the risk of different cancer types over time.

Furthermore, the National Comprehensive Cancer Network’s clinical practice guideline on “Uterine Neoplasms” (Version 3.2026) does not mention anti-Mullerian hormone.

Measurement of L1 Cell Adhesion Molecule (L1CAM) Expression for Prognosis of Endometrial Cancer

Guo and colleagues (2021) noted that previous studies have reported that levels of L1 cell adhesion molecule (L1CAM) indicate poor prognosis for patients with various solid tumors; however, the prognostic significance of L1CAM in endometrial cancer (EC) has remained controversial. In a systematic review and meta-analysis, these investigators examined the prognostic value of L1CAM in EC. They identified all studies related to the association between L1CAM expression and clinical characteristics of EC by searching the PubMed, Medline, Embase, and Web of Science databases. The primary outcomes of the meta-analysis were the hazard ratios (HRs) for overall survival (OS) and disease-free survival (DFS), while the secondary outcomes were odds ratios (ORs) for clinicopathological characteristics. Publication bias and sensitivity analyses were conducted to ensure the reliability of the results. A total of 17 studies encompassing 7,146 patients were eligible for the meta-analysis. The results showed that L1CAM over-expression was significantly associated with decreased OS (HR = 2.87, 95% CI: 1.81 to 4.55, p < 0.001) and DFS (HR = 3.32, 95% CI: 1.99 to 5.55, p < 0.001) in patients with EC. High L1CAM expression was also related to adverse clinicopathological characteristics. The authors concluded that the findings of this systematic review indicated that high L1CAM expression was correlated with poor survival outcomes and adverse clinicopathological parameters in patients with EC; thus, L1CAM expression could serve as a potential prognostic predictor for women with EC. Moreover, they stated that additional prospective studies or randomized clinical trials are needed to support these conclusions.

The authors acknowledged several drawbacks in this review/meta-analysis. First, follow-up duration, which is an important factor for both OS and DFS analyses, was not included in some of the studies, potentially affecting the results of both OS and DFS. Second, the sample size of this meta-analysis was limited. Although the researchers identified 160 relevant studies through a preliminary database search, only 17 were eventually included after screening—9 studies (5,116 patients) for OS analysis and 8 studies (3,970 patients) for DFS analysis. A larger sample size would have made the conclusions more persuasive. Third, all the included studies were retrospective, which may have introduced selection bias. Fourth, although the investigators attempted to include the most persuasive evidence of L1CAM expression in the prognosis of EC and to exclude disturbances from various risk factors, their analysis was not based on individual patient-level data, and they did not examine the equivalent distribution of numerous variables related to baseline characteristics of patients, such as age, race, histological types of malignancies, surgery, and adjuvant treatment, between the high-expression and low-expression groups.

Metabolomics (Metabolic Biomarkers) for Diagnosis and Prognosis of Endometrial Cancer

In a systematic review, Tokarz and colleagues (2020) examined the contribution of metabolomics to the identification of diagnostic and prognostic biomarkers for uterine diseases. These diseases are diagnosed invasively, which can lead to delayed treatment and worse clinical outcomes. New options for diagnosis and prognosis are needed. The researchers searched PubMed, OVID, and Scopus for research papers on metabolomics in physiological fluids and tissues from patients with uterine diseases, identifying 484 records. Based on inclusion and exclusion criteria, 44 studies were included in the review. Relevant data were extracted following the PRISMA checklist, and quality was evaluated using the QUADOMICS tool. The selected metabolomics studies analyzed plasma, serum, urine, peritoneal fluid, endometrial and cervico-vaginal fluid, ectopic/eutopic endometrium, and cervical tissue. In endometriosis, diagnostic models successfully discriminated patients from healthy and infertile controls. In cervical cancer, diagnostic algorithms differentiated patients from controls, as well as those with good or bad prognosis and those with or without response to chemotherapy. In endometrial cancer (EC), several models stratified patients from controls and recurrent from non-recurrent patients. The authors concluded that metabolomics is useful for constructing diagnostic models; however, most studies were in the discovery phase and require additional research to select reliable biomarkers for validation and translation into clinical practice. They emphasized that the large number of investigations into biomarker discovery in uterine diseases through metabolomics indicates that its potential has been recognized in gynecology and reproduction; however, future studies are needed for appropriate validation of identified biomarkers and to ensure their specificity. Once these requirements are met, it is expected that algorithms based on metabolites will contribute to better diagnostic options for endometriosis and provide diagnostic and prognostic alternatives for cervical cancer and EC.

Njoku and associates (2021) noted that EC is the most common malignancy of the female genital tract and a major cause of morbidity and mortality in women. Early detection is crucial for ensuring good outcomes; however, the lack of minimally invasive screening tools presents a significant barrier. Most ECs are obesity-driven and develop in the context of severe metabolomic dysfunction; thus, blood-derived metabolites may provide clinically relevant biomarkers for EC detection. The researchers analyzed plasma samples from women with a body mass index (BMI) of 30 kg/m² or greater, comparing those with endometrioid EC (cases, n = 67) to those with histologically normal endometrium (controls, n = 69), using a mass spectrometry-based metabolomics approach. Eighty percent of the samples were randomly selected to serve as a training set, while the remaining 20% were used to evaluate test performance. Robust predictive models (AUC greater than 0.9) for EC detection based on artificial intelligence algorithms were developed and validated. Phospholipids were significant as biomarkers of EC, with sphingolipids (sphingomyelins) being particularly discriminatory in post-menopausal women. An algorithm combining the top 10 performing metabolites achieved a prediction accuracy of 92.6% (AUC of 0.95) for EC detection. The authors concluded that these findings suggest that a simple blood test could enable early detection of EC and provide the basis for a minimally invasive screening tool for women with a BMI of 30 kg/m² or greater. Moreover, they stated that further studies are needed to validate the biomarker candidates and examine their role in endometrial carcinogenesis.

The authors acknowledged several drawbacks of this study design. First, the metabolite panel may not identify non-endometrioid or non-obesity-related tumors. It was also unclear how well the biomarkers would perform in other high-risk groups, such as the elderly, those with post-menopausal bleeding, or individuals with Lynch syndrome. The relatively small sample size and the associated difficulty in controlling for potential confounding factors were additional drawbacks. Furthermore, several discriminatory metabolites could not be biochemically identified, which limited their clinical implementation.

Kozar and co-workers (2021) examined the metabolomic profile of serum from EC patients with the aim of identifying novel diagnostic biomarkers that could be used, especially for early disease detection. These researchers employed targeted metabolomic serum profiling based on HPLC-TQ/MS, examining women with EC (n = 15) and controls (n = 21) for 232 endogenous metabolites. The top-performing biomarkers included ceramides, acylcarnitines, and 1-methyl adenosine. The top four biomarkers combined achieved 94% sensitivity with 75% specificity and an AUC of 92.5% (CI: 90.5% to 94.5%). Individual markers also provided significant predictive values: C16-ceramide achieved sensitivity of 73%, specificity of 81%, and AUC of 0.83; C22-ceramide had sensitivity of 67%, specificity of 81%, and AUC of 0.77; hydroxyhexadecenoylcarnitine showed sensitivity of 60%, specificity of 96%, and AUC of 0.76; and 1-methyladenosine had sensitivity of 67%, specificity of 81%, and AUC of 0.75. However, the individual markers did not reach the high sensitivity and specificity of the four-biomarker combination. The authors concluded that using mass spectrometry-targeted metabolomic profiling, ceramides, acylcarnitines, and 1-methyladenosine were identified as potential diagnostic biomarkers for EC and possibly even for screening programs.

The authors noted several drawbacks of this study. First, the number of both EC patients and control participants was relatively small compared to the large number of parameters studied. Furthermore, all patients were recruited from a homogeneous population of Caucasian women from a specific region. Finally, the study focused only on known metabolites, which prevented the investigators from identifying other potential biomarkers. To achieve higher reliability of results, more samples should be included, preferably from different centers with a more heterogeneous population.

Neutrophil Gelatinase-Associated Lipocalin for Diagnosis of Endometrial Cancer

Roli and colleagues (2017) noted that some studies have reported differentially altered neutrophil gelatinase-associated lipocalin (NGAL) levels in several malignancies. These researchers evaluated NGAL measured in plasma or urine as both prognostic and diagnostic marker for different types of human tumors. They performed systematic electronic searches in Medline, Embase and CRDTAS. Studies were included if they evaluated NGAL as a prognostic or diagnostic marker for human cancers. The selection of the studies, screening of the full texts and data extraction were conducted independently by 2 authors. They used the random-effects model for the meta-analyses. A methodological assessment was completed. These investigators included 35 studies dedicated to colorectal, pancreas, breast, thyroid, gastric, kidney, endometrial, brain, liver, lung, esophageal, oral and ovarian cancers. Meta-analyses showed that, in patients with colorectal and breast cancer, positive NGAL expression was associated with a decrease of disease-free survival (hazard ratio [HR] = 2.27, 95% CI: 1.54 to 3.36; HR = 1.78, 95% CI: 1.33 to 2.38, respectively). NGAL was a negative prognostic marker of overall survival (OS) in colorectal (HR = 2.37, 95% CI: 1.68 to 3.34) and endometrial (HR = 4.38, 95% CI: 1.9 to 10.12) cancers. Discriminative power of NGAL between cancer patients and control was moderate in colorectal cancer (area under the curve [AUC] = 0.6; pooled sensitivity 0.56; pooled specificity 0.72), acceptable in pancreatic cancer (AUC = 0.8; pooled sensitivity 0.6; pooled specificity 0.8) and good in thyroid cancer (AUC = 0.9; pooled sensitivity 0.85; pooled specificity 0.96). The authors concluded that NGAL determination in plasma and urine could be useful in the prognosis of colorectal and breast cancer, but its prognostic accuracy remains uncertain for other human tumors.

Polymorphism Testing of the Fat Mass and Obesity-Associated (FTO) Genes for Screening and Diagnosis of Endometrial Cancer

Khudheyer Almy et al. (2023) endometrial and ovarian tumors are almost mechanistically affected by reproductive hormones. Ovarian cancer may be explained as metastatic or synchronous primary ovarian cancer, and the specific diagnosis is a challenge. These investigators examined the mutations in fat mass and obesity-associated (FTO) genes and evaluated the association of these mutations with the risk of EC and ovarian cancer as well as with cancer grade and stage. Blood samples were collected from 48 EC and ovarian cancer cases and 48 healthy women. Genomic DNA was extracted, and PCR was carried out to amplify FTO exons 4-9. Sanger sequencing identified 6 different novel mutations submitted to DDBJ: p.W278G and p.G284G in exon 4, p.S318I and p.A324G in exon 5 and 2 mutations in intron 4. Other mutations were also detected in FTO gene sequencing results, rs112997407 in intron 3, rs62033438, rs62033439, rs8048254 and rs8046502 in intron 4. The novel p.W278G, p.S318I and p.A324G mutations were predicted to be damaging. These researchers did not find a significant association for all variables with cancer risk or clinical stage and grade except for rs62033438 variants, which showed a significant association with cancer grade, especially AA genotype (OR = 15, 95% CI: 1.32 to 169.88, p = 0.03). The authors concluded that the statistical analysis did not clarify whether FTO mutations are implicated in cancer. Moreover, these researchers stated that further studies with more samples are needed to provide a more accurate picture of the correlation between FTO mutations and EC and ovarian cancer susceptibility.

Sentinel Lymph Node (SLN) Mapping

Bodurtha and associates (2017) noted that in the staging of endometrial cancer, there remains controversy regarding the role of sentinel lymph node (SLN) mapping compared to other nodal assessment strategies. These researchers conducted a systematic review to evaluate the diagnostic accuracy and clinical impact of SLN mapping in the management of endometrial cancer. They searched Medline, Embase, and the Cochrane Central Registry of Controlled Trials for studies published in English before March 25, 2016. Studies were included if they contained 10 or more women with endometrial cancer and reported on the detection rate, sensitivity, and/or impact on treatment or survival of SLN mapping. Two authors independently reviewed abstracts and full-text articles for inclusion and assessed study quality. The detection rate, sensitivity, and factors associated with successful mapping (study size, BMI, tumor histology and grade, injection site, dye type) were synthesized through random-effects meta-analyses and meta-regression. The investigators identified 55 eligible studies, which included 4,915 women. The overall detection rate of SLN mapping was 81% (95% CI: 77 to 84) with a 50% (95% CI: 44 to 56) bilateral pelvic node detection rate and a 17% (95% CI: 11 to 23) para-aortic detection rate. There was no difference in detection rates by patient BMI or tumor histology and grade. The use of indocyanine green (ICG) increased the bilateral detection rate compared with blue dye. Additionally, cervical injection increased the bilateral SLN detection rate but decreased the para-aortic detection rate compared with alternative injection techniques. Intra-operative SLN frozen section increased the overall and bilateral detection rates. The sensitivity of SLN mapping to detect metastases was 96% (95% CI: 91 to 98); ultra-staging did not improve sensitivity. Compared with women staged with complete lymphadenectomy, women staged with SLN mapping were more likely to receive adjuvant treatment. The authors concluded that SLN mapping was feasible and accurately predicted nodal status in women with endometrial cancer. They stated that the current data favored the use of cervical injection techniques with ICG and suggested that SLN mapping may be considered an alternative standard of care in the staging of women with endometrial cancer.

Rossi and co-workers (2017) measured the sensitivity and negative predictive value (NPV) of SLN mapping compared with the gold standard of complete lymphadenectomy in detecting metastatic disease for endometrial cancer. In the FIRES multi-center, prospective cohort study, patients with clinical stage 1 endometrial cancer of all histologies and grades undergoing robotic staging were eligible for study inclusion. Patients received a standardized cervical injection of ICG and SLN mapping followed by pelvic lymphadenectomy with or without para-aortic lymphadenectomy. A total of 18 surgeons from 10 centers (tertiary academic and community non-academic) in the USA participated in the trial. Negative SLNs (by hematoxylin and eosin staining on sections) were ultra-staged with immunohistochemistry for cytokeratin. The primary endpoint, sensitivity of the SLN-based detection of metastatic disease, was defined as the proportion of patients with node-positive disease with successful SLN mapping who had metastatic disease correctly identified in the SLN. Patients who had mapping of at least one SLN were included in the primary analysis (per protocol). All patients who received the study intervention (injection of dye), regardless of mapping result, were included as part of the assessment of mapping and in the safety analysis in an intention-to-treat manner. Between August 1, 2012, and October 20, 2015, a total of 385 patients were enrolled; SLN mapping with complete pelvic lymphadenectomy was performed in 340 patients, and para-aortic lymphadenectomy was done in 196 (58%) of these patients. A total of 293 (86%) patients had successful mapping of at least one SLN; 41 (12%) patients had positive nodes, 36 of whom had at least one mapped SLN. Nodal metastases were identified in the SLNs of 35 (97%) of these 36 patients, yielding a sensitivity to detect node-positive disease of 97.2% (95% CI: 85.0 to 100), and an NPV of 99.6% (97.9 to 100). The most common grade 3 to 4 adverse events (AEs) or serious AEs (SAEs) were postoperative neurological disorders (4 patients) and postoperative respiratory distress or failure (4 patients). A total of 22 patients had SAEs, with one related to the study intervention: a ureteral injury incurred during SLN dissection. The authors concluded that SLNs identified with ICG had a high degree of diagnostic accuracy in detecting endometrial cancer metastases and can safely replace lymphadenectomy in the staging of endometrial cancer. They noted that sentinel lymph node biopsy will not identify metastases in 3% of patients with node-positive disease but has the potential to expose fewer patients to the morbidity of a complete lymphadenectomy.

How and colleagues (2018) stated that the appropriate extent of lymphadenectomy in clinically early-stage endometrial cancer remains controversial, but SLN mapping has emerged as an alternative staging strategy until the advent of molecular prognostic markers. These researchers performed a systematic review of the literature to determine pooled estimates for SLN detection rate and diagnostic accuracy while exploring the impact of SLN on adjuvant therapy and oncologic outcomes. They conducted a systematic search utilizing Medline, Embase, and Web of Science electronic databases for all studies published in English until October 31, 2017. Studies were included for review and potential aggregate analyses if they contained at least 30 endometrial cancer patients undergoing SLN mapping and reported on detection rates (overall, bilateral, or para-aortic) or diagnostic accuracy (sensitivity and NPV). Pooled estimates were calculated via meta-analyses utilizing a random-effects model. Studies reporting on the impact of SLN on adjuvant therapy, as well as studies comparing SLN mapping to completion lymphadenectomy, were qualitatively reviewed and analyzed. These investigators identified 48 eligible studies, which included 5,348 patients for review and inclusion in the meta-analysis for SLN detection or diagnostic accuracy. The pooled SLN detection rates were 87% (95% CI: 84 to 89%, 44 studies) for overall detection, 61% (95% CI: 56 to 66%, 36 studies) for bilateral detection, and 6% (95% CI: 3 to 9%, 31 studies) for para-aortic detection. The use of ICG improved overall (94%, 95% CI: 92 to 96%, 19 studies) SLN detection rates compared to blue tracer (86%, 95% CI: 83 to 89%, 31 studies) or technetium-99 (86%, 95% CI: 83 to 89%, 25 studies). This trend was similarly observed in terms of bilateral detection rates (74% versus 59% versus 57%, respectively). There was no difference in para-aortic SLN detection rates between each tracer. The pooled estimates for diagnostic accuracy for 34 studies were 94% (95% CI: 91 to 96%) for sensitivity and 100% (95% CI: 99 to 100%) for NPV. The diagnostic accuracy of SLN mapping was not negatively affected in patients with high-grade endometrial histology. Patients with SLN mapping were more likely to receive adjuvant therapy and did not have inferior survival or recurrence outcomes compared to those undergoing completion lymphadenectomy. The authors concluded that SLN mapping is a feasible and accurate alternative to stage patients with endometrial cancer. Utilizing ICG resulted in the highest SLN detection rates. Moreover, they stated that future studies should prospectively examine the impact of SLN mapping on progression-free survival (PFS) and overall survival (OS).

Yu et al. (2022) stated that total hysterectomy with lymph node assessment is the current standard of care (SOC) for surgical staging in apparent early-stage endometrial cancer. Compared to traditional complete pelvic lymphadenectomy with or without para-aortic lymphadenectomy, SLN mapping results in fewer surgical complications, decreased operative time, and lower rates of chronic lymphedema. The technique is endorsed by the National Comprehensive Cancer Network (NCCN) and the Society of Gynecologic Oncology guidelines, and over the last 20 years, the majority of gynecologic oncologists worldwide have adopted SLN mapping into their practice. However, as the results of the initial SLN studies were mostly based on low-grade tumors, the adoption of the technique in high-grade tumors has been slower and more controversial. These investigators discussed the most recent studies examining SLN mapping in high-grade endometrial cancers. The results of these studies suggested that the SLN detection rate is acceptably high and the negative predictive value (NPV) is sufficiently low to support the use of SLN mapping in high-grade endometrial tumors to replace complete lymphadenectomy. The validity of SLN mapping techniques does, however, require following a standard algorithm, and success also depends on surgeon expertise. Moreover, the impact of SLN mapping on overall survival in high-grade tumors requires future prospective randomized studies. Finally, a transition toward near-universal SLN mapping techniques for endometrial cancers could significantly impact the adequacy of gynecologic oncology fellows' surgical training and competency in lymphadenectomy.

In a prospective, multi-center study, Burg et al. (2022) examined the incidence of SLN metastases and the contribution of SLN mapping in presumed low- and intermediate-risk endometrial cancer. Patients underwent SLN mapping using cervical injections of indocyanine green and a minimally invasive hysterectomy with bilateral salpingo-oophorectomy. The primary outcome was the incidence of SLN metastases, leading to adjusted adjuvant treatment. Secondary outcomes included the SLN detection rate and the occurrence of complications. Descriptive statistics and univariate general linear model analyses were used. A total of 152 patients were enrolled, with overall and bilateral SLN detection rates of 91% and 61%, respectively. At final histology, 78.9% of patients (n = 120) had truly low- and intermediate-risk endometrial cancer. Macro- and micro-metastases were present in 11.2% (n = 17/152), and 3 patients had isolated tumor cells (2.0%); 9 patients (5.9%) had adjuvant radiotherapy added based on SLN metastases only. In 2.0% of patients with high-risk disease, adjuvant therapy was more limited due to negative SLNs. The authors concluded that the findings of this study emphasized the importance of SLN mapping in presumed early-stage, grade 1 and 2 endometrial cancer, leading to individualized adjuvant management, resulting in less under-treatment and over-treatment.

Raffone et al. (2022) stated that in endometrial cancer patients, SLN biopsy has shown the potential to reduce postoperative morbidity and long-term complications, and to improve the detection of low-volume metastasis through ultra-staging. However, while it has shown high sensitivity and feasibility in low-risk endometrial cancer patient groups, its role in high-risk groups is still unclear. These researchers examined the role of SLN biopsy through the cervical injection of ICG in high-risk groups of early-stage endometrial cancer patients. Among the several tracers and injection sites proposed for SLN mapping, the cervical injection of fluorescent dye ICG has shown the highest bilateral pelvic detection rate and is currently recommended. A total of seven electronic databases were searched from their inception to February 2021 for studies that allowed data extraction about the detection rate and accuracy of SLN biopsy through the cervical injection of ICG in high-risk groups of early-stage endometrial cancer patients. These investigators calculated pooled sensitivity, false negative (FN) rate, detection rate of SLN per hemipelvis (DRh), detection rate of SLN per patient (DRp), and bilateral detection rate of SLN (DRb), with 95% CI. A total of five observational cohort studies (three prospective and two retrospective) assessing 578 high-risk endometrial cancer patients were included. SLN biopsy sensitivity in detecting endometrial cancer metastasis was 0.90 (95% CI: 0.03 to 0.95). The FN rate was 2.8% (95% CI: 0.6% to 11.6%). DRh was 88.4% (95% CI: 86% to 90.5%), DRp was 96.6% (95% CI: 94.7% to 97.8%), and DRb was 80% (95% CI: 75.4% to 83.9%). The authors concluded that SLN biopsy through ICG cervical injection may be routinely adopted instead of systematic pelvic and para-aortic lymphadenectomy in surgical staging for high-risk groups of early-stage endometrial cancer patients, as well as in low-risk groups.

In a retrospective study, Mueller et al. (2023) compared outcomes of patients with pre-malignant endometrial pathology undergoing hysterectomy with or without SLN removal. Outcomes of interest included surgical adverse events (AEs), cancer status on final pathology, postoperative treatment, and The Cancer Genome Atlas (TCGA) molecular risk profiles. These researchers identified patients with pre-malignant pathology on pre-operative endometrial biopsy who underwent hysterectomy with or without SLN mapping/excision at their institution from January 1, 2017, to December 31, 2021. Clinical, pathologic, surgical, and TCGA profiling data were abstracted. Appropriate statistical tests were used. Of 221 patients identified, 161 (73%) underwent hysterectomy with SLN excision and 60 (27%) underwent hysterectomy without SLN excision. Median age and BMI were similar between groups. The median operative time was 130 minutes for those who underwent SLN mapping/excision versus 136 minutes for those who did not (p = 0.6); 30-day postoperative AE rates were 9% (n = 15/161) and 13% (n = 8/60), respectively (p = 0.9); 98 (44%) of 221 patients had grade 1-2 endometrioid endometrial cancer on final pathology (4 [4%] were stage IB or higher); 10 (10%) of 98 patients, all within the SLN group, received adjuvant treatment. Among all patients, of 33 (15%) with TCGA molecular classification data, 27 (82%) had copy number-low, 3 (9%) had micro-satellite instability (MSI)-high, 2 (6%) had POLE-ultra-mutated, and 1 (3%) had copy number-high disease. The authors concluded that SLN assessment appeared safe, detected a small number of occult nodal metastases for those up-staged, and provided additional staging information that could guide adjuvant treatment. They stated that SLN mapping should be discussed in pre-operative counseling and offered using a shared decision-making approach.

In a retrospective study, Bogani et al. (2023) compared outcomes after hysterectomy and hysterectomy plus sentinel node mapping (SNM) in endometrial cancer patients. These researchers collected data from endometrial cancer patients treated between 2006 and 2016 in nine referral centers. The study population included 398 (69.5%) patients having hysterectomy and 174 (30.5%) patients having hysterectomy plus SNM. As a result of the adoption of a propensity-score matched analysis, these investigators selected two homogeneous cohorts of patients (150 having hysterectomy only versus 150 having hysterectomy plus SNM). The SNM group had a longer operative time but did not correlate with hospital length of stay (LOS) and estimated blood loss (EBL). Overall severe complication rates were similar between groups (0.7% in the hysterectomy group versus 1.3% in the hysterectomy plus SNM group; p = 0.561). No lymphatic-specific complications occurred. Overall, 12.6% of patients having SNM were diagnosed with disease harboring in their lymph nodes. The adjuvant therapy administration rate was similar between groups. Considering patients having SNM, 4% of patients received adjuvant therapy based on nodal status alone; all other patients received adjuvant therapy also based on uterine risk factors. The 5-year disease-free survival (DFS) (p = 0.720) and overall survival (OS) (p = 0.632) were not influenced by the surgical approach. The authors concluded that hysterectomy (with or without SNM) was a safe and effective method for managing endometrial cancer patients. Potentially, these data support the omission of side-specific lymphadenectomy in cases of unsuccessful mapping.

Furthermore, the National Comprehensive Cancer Network’s clinical practice guideline on “Uterine Neoplasms” (Version 3.2026) states that “SLN identification should always be done prior to hysterectomy, except in cases where a bulky uterus must be removed to allow access to iliac vessels and lymph nodes.”

Serum Human Epididymis Protein 4 (HE4)

In a meta-analysis, Bie and Zhang (2014) evaluated the clinical value of serum human epididymis protein 4 (HE4) in the diagnosis of endometrial carcinoma (EC). These researchers used MEDLINE, EMBASE, Cochrane Library, and CBM databases to search the literature. The meta-analysis was performed using Meta-Disc 1.4 software. All data showed that the major advantage of HE4 lies in its specificity in EC diagnosis. Its sensitivity in serum was not as high as expected; however, this evidence was not sufficient. The authors concluded that additional studies, particularly to evaluate HE4's capability in identifying EC at an early stage, are needed.

In a prospective study, Minar et al. (2015) evaluated the use of HE4 and CA-125 biomarkers in the differential diagnosis of malignant and benign endometrial tumors in a population of Czech women. This study included 115 patients with endometrioid adenocarcinoma and 106 patients with benign endometrial tumors in the control group. They were diagnosed with endometrial biopsy in the period from July 2010 to June 2013. The patients with cancer underwent definitive surgical treatment to determine the stage of the disease. The median and ranges of serum levels were determined in relation to the histological result (benign versus malignant disease). While analyzing the two groups of patients with different histology, a statistically significant difference (p < 0.05) was demonstrated only in HE4; with a cut-off of 48.5 pmol/L, sensitivity of 87.8%, specificity of 56.6%, and NPV of 81.1% were achieved. The authors concluded that the diagnostic benefit of HE4 can be considered especially in patients with an increased risk of endometrial cancer and in patients with serious internal comorbidities. They stated that HE4 could help, in combination with clinical and ultrasound findings, in the differentiation of prognostically various groups of patients and in decision-making related to the individualization of the treatment plan. However, they noted that the optimal cut-off for HE4 has not yet been established, and to do so, more research with larger studies and their comparative analysis will be required.

The National Comprehensive Cancer Network’s clinical practice guideline on “Uterine Neoplasms” (Version 3.2026) does not mention serum human epididymis protein 4 (HE4) for the diagnosis of EC.

Single Nucleotide Polymorphism Testing

Bafligi and colleagues (2020) noted that endometrial cancer is one of the most commonly diagnosed cancers in women. Although there is a hereditary component to endometrial cancer, most cases are thought to be sporadic and related to lifestyle factors. These researchers reviewed prospective and retrospective case-control studies, meta-analyses, and genome-wide association studies (GWAS) to identify genomic variants that may be associated with endometrial cancer risk. They searched Medline, Embase, and CINAHL from 2007 to 2019 without restrictions, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2009 guidelines. The search yielded a total of 3,015 hits. After excluding duplicates, 2,674 abstracts were screened, and 453 full texts were evaluated based on pre-defined screening criteria, resulting in 149 articles eligible for inclusion. The investigators found that single nucleotide polymorphisms (SNPs) in HNF1B, KLF, EIF2AK, CYP19A1, SOX4, and MYC were strongly associated with incident endometrial cancer; 19 variants were reported with genome-wide significance, and a further five with suggestive significance. No convincing evidence was found for the widely studied MDM2 variant rs2279744. Publication bias and false discovery rates were noted throughout the literature. The authors concluded that endometrial cancer risk may be influenced by SNPs in genes involved in cell survival, estrogen metabolism, and transcriptional control. Moreover, they stated that larger cohorts are needed to identify more variants with genome-wide significance.

These investigators noted that this study compiled and presented available information for the extensively studied, yet unproven in large datasets, SNP309 variant in MDM2. Currently, there is no convincing evidence for an association between this variant and endometrial cancer risk. Furthermore, of all the studies, only one accounted for the opposing effect of a nearby variant, SNP285, in their analyses. Therefore, these researchers concluded that until confirmed by a sufficiently large GWAS, this variant should not be considered significant in influencing the risk of endometrial cancer and thus should not be included in a polygenic risk score (PRS). This conclusion also applies to the majority of the SNPs reported in candidate-gene studies, as the numbers fell far short of being able to detect genuine signals. This systematic review presented the most up-to-date evidence for endometrial cancer susceptibility variants, emphasizing the need for further large-scale studies to identify more important variants and validate these associations.

Furthermore, the National Comprehensive Cancer Network’s clinical practice guideline on “Uterine Neoplasms” (Version 3.2026) does not mention single nucleotide polymorphism testing.

Telomeres and Telomerase Activity for Diagnosis and/or Screening of Endometrial Cancer

Valentijn et al. (2015) conducted a prospective observational study involving 196 women to evaluate the effects of ovarian hormone regulation of telomerase activity (TA) on endometrial telomere length (TL) and epithelial cell proliferation. Endometrial TL was significantly longer than matched blood TL (4,893 ± 929 bp vs. 3,955 ± 557 bp; p = 0.002) and was inversely correlated with serum progesterone levels (r = -0.54, n = 58), suggesting tissue-specific regulation. Proliferating endometrial epithelial cells demonstrated high TA and shorter TL both in vivo and in vitro, while TL was significantly shorter during the progesterone-dominant mid-secretory phase compared with the proliferative phase (p = 0.0002). Progestagen treatment suppressed epithelial TA in vivo and reduced TA in both explant (p = 0.01) and in vitro cultures (p = 0.02), whereas mifepristone increased telomerase protein expression (p < 0.05). Additionally, the telomerase inhibitor imetelstat significantly reduced TA (p = 0.03) and cell proliferation (p = 0.009) and disrupted endometrial glandular architecture in 3D culture (p = 0.03). The authors concluded that telomerase may represent a potential therapeutic target for proliferative endometrial disorders such as endometriosis. Key limitations included the short-term in vitro evaluation of telomerase inhibition in a monocellular system requiring in vivo confirmation, and the inclusion of a high proportion of overweight women (BMI >25) in one study group, which may limit generalizability.

Hapangama and colleagues (2017) stated that eukaryotic chromosomal ends are linear and are protected by nucleoprotein complexes known as telomeres. The complex structural anatomy and the diverse functions of telomeres as well as the unique reverse transcriptase enzyme, telomerase that maintains telomeres are under intensive scientific scrutiny. Both are involved in many human diseases including cancer, but also in ageing and chronic disease such as diabetes. Their intricate involvement in many cellular processes and pathways is being dynamically deciphered in many organs including the endometrium. These investigators summarized the current knowledge on the topic of telomeres and telomerase and their potential role in providing plausible explanations for endometrial aberrations related to common gynecological pathologies. They outlined the recent major findings in telomere and telomerase functions in the context of endometrial biology; and highlighted the contemporary discoveries in hormonal regulation, normal endometrial regeneration, stem cells and common gynecological diseases such as endometriosis, infertility, recurrent reproductive failure and endometrial cancer (EC). These researchers performed systematic PubMed (Medline) and Ovid searches using the key words: telomerase, telomeres, telomere length, human telomerase reverse transcriptase, telomeric RNA component, with endometrium, hormonal regulation, endometrial stem/progenitor cells, endometrial regeneration, endometriosis, recurrent miscarriage, infertility, endometrial hyperplasia, EC and uterine cancer.  Publications used in this review dated from 1995 to June 31, 2016. The human endometrium is a unique somatic organ, which displays dynamic TA related to the menstrual cycle. Telomerase is implicated in almost all endometrial pathologies and appeared to be crucial to endometrial stem cells. In particular, it is vital for normal endometrial regeneration, providing a distinct route to formulate possible curative, non-hormonal therapies to treat chronic endometrial conditions. Furthermore, the current understanding of telomere maintenance in EC is incomplete. Data derived from other malignancies on the role of telomerase in carcinogenesis cannot be extrapolated to EC because unlike in other cancers, TA is already present in proliferating healthy endometrial cells. The authors concluded that since telomerase is pivotal to endometrial regeneration, further studies elucidating the role of telomeres, telomerase, their associated proteins and their regulation in normal endometrial regeneration as well as their role in endometrial pathologies are essential.

UBE2C, WNT5a and ZEB1 as Biomarkers of Endometrial Cancer

Zhang et al. (2023) stated that ubiquitin-conjugating enzyme E2C (UBE2C), its over-expression promotes tumor progression, is a key component of the ubiquitin conjugating proteasome complex. Epithelial-mesenchymal transition, which is lost epithelial features and gained mesenchymal features in some epithelial cancers, is involved in epithelial cancers' invasiveness and metastasis. These researchers examined the expression of UBE2C, WNT5α, and E-cad in EC and their clinical significance. The expression of UBE2C, WNT5α, and ZEB1 in 125 cases EC tissues were detected by IHC. Patients clinico-pathological, demography, and follow-up data were also collected. Positive rates of expression of UBE2C and ZEB1 were significantly higher in EC tissues when compared with the control tissues. The positive expression of UBE2C and ZEB1 were positively associated with tumor stages, local lymph node metastasis, and International FIGO stages. The positive rate of expression of WNT5a was significantly lower in EC tissues when compared with the control tissues. And positive expression of E-cad was inversely related to tumor stages, lymph node metastasis stages, and FIGO stages. Kaplan-Meier analyses showed that positive expression of UBE2C or ZEB1 for EC patients had unfavorably OS time when compared with patients with negative expression of UBE2C or ZEB1. In addition, EC patients with positive expression of WNT5a had favorably OS time when compared with EC patients with negative expression of WNT5a. Multi-variate analysis showed that positive expression UBE2C, WNT5α, and ZEB1, as well as FIGO stages were independent prognostic factors for EC patients. The authors concluded that UBE2C, WNT5a, and ZEB1 should be considered promising biomarkers for prediction of invasiveness and prognosis. Moreover, these researchers stated that the methodology of subjects in this study was relatively simple; further studies with more methodologies (such as in-vitro as well as in-vivo models) are needed to verify the present observation.

Urine MicroRNAs Expression

Zavesky et al. (2015) stated that among gynecological cancers, epithelial ovarian cancers are the most deadly, while endometrial cancers are the most common diseases. Efforts to establish relevant novel diagnostic, screening, and prognostic markers aim to help reduce the high levels of mortality, chemo-resistance, and recurrence, particularly in ovarian cancer. MicroRNAs, a class of post-transcriptional regulators, have emerged as promising diagnostic and prognostic markers associated with various diseased states recently. Urine has been shown to be a source of microRNAs several years ago; however, there has been a lack of information on urine microRNA expression in ovarian and endometrial cancers until now. In this pilot study, these researchers examined the expression of candidate cell-free urine microRNAs in ovarian cancer and endometrial cancer patients using quantitative real-time PCR. They compared the expression between pre- and post-surgery ovarian cancer samples, and between patients with ovarian and endometrial cancers and healthy controls, within three types of experiments. These experiments evaluated three different isolation methods of urine RNA, representing two supernatant and one exosome fractions of extracellular microRNA. In ovarian cancer, these investigators found miR-92a significantly up-regulated and miR-106b significantly down-regulated in comparison with control samples. In endometrial cancer, only miR-106b was found to be significantly down-regulated compared to control samples. Using exosome RNA, no significant deregulations in microRNA expression could be found in either of the cancers investigated. The authors proposed that more research should now focus on confirming the diagnostic potential of urine microRNAs in gynecological cancers using more clinical samples and large-scale expression profiling methods.

Giglio et al. (2019) noted that endometrial cancer is the most common gynecologic malignancy in developed countries. Estrogen-dependent tumors (type I, endometrioid) account for 80% of cases, while non-estrogen-dependent tumors (type II, non-endometrioid) account for the rest. Endometrial cancer type I is generally thought to develop via precursor lesions along with the increasing accumulation of molecular genetic alterations. Endometrial hyperplasia with atypia/endometrial intraepithelial neoplasia is the least common type of hyperplasia, but it is the type most likely to progress to type I cancer, whereas endometrial hyperplasia without atypia rarely progresses to carcinoma. MicroRNAs are a class of small, non-coding, single-stranded RNAs that negatively regulate gene expression mainly by binding to the 3'-untranslated region of target mRNAs. In the current study, these researchers identified a microRNA signature (miR-205, miR-146a, miR-1260b) able to discriminate between atypical and typical endometrial hyperplasia in two independent cohorts of patients. The identification of molecular markers that can distinguish between these two distinct pathological conditions is considered highly useful for the clinical management of patients because hyperplasia with atypical changes is associated with a higher risk of developing cancer. These investigators showed that the combination of miR-205, -146a, and -1260b has the best predictive power in discriminating these two conditions (greater than 90%). With the aim of finding a biological role for these three microRNAs, these researchers focused their attention on a common putative target involved in endometrial carcinogenesis: the onco-suppressor gene SMAD4. They showed that miRs-146a, -205, and -1260b directly target SMAD4, and their enforced expression induced proliferation and migration of endometrioid cancer-derived cell lines, specifically Hec1a cells. The authors concluded that these data suggest that microRNA-mediated impairment of the TGF-β pathway, due to inhibition of its effector molecule SMAD4, is a relevant molecular alteration in endometrial carcinoma development. These researchers stated that these findings show a potential diagnostic role of this microRNA signature for the accurate diagnosis of endometrial hyperplasia with atypia/endometrial intraepithelial neoplasia and improve the understanding of their pivotal role in SMAD4 regulation.

The National Comprehensive Cancer Network’s clinical practice guideline on “Uterine Neoplasms” (Version 3.2026) does not mention microRNA expression for the diagnosis of EC.

References