PI3K Pathway Effectors pAKT and FOXO1 as Novel Markers of Endometrioid Intraepithelial Neoplasia

Predicting Progestin Therapy Response With PTEN, PAX2, and β-Catenin in Patients With Endometrioid Precancer

This study investigates the predictive value of biomarkers PTEN, PAX2, and β-catenin for therapeutic outcomes in patients with atypical endometrial hyperplasia or endometrioid intraepithelial neoplasia undergoing progestin therapy. In a retrospective study of 128 patients, we analyzed a total of 351 endometrial biopsy samples and categorized outcomes into responders (absence of residual disease) and nonresponders (presence of residual disease). We found aberrant biomarker expression in pretreatment cases: 48% for PTEN, 65% for PAX2, and 36% for β-catenin. Approximately 77.3% of patients responded to progestin treatment, with nonresponders showing significantly higher initial PTEN loss (75.86% vs 39.79%, P < 0.001). Nonresponders also demonstrated significant PTEN loss (53.33% vs 20.55%, P < 0.001), PAX2 loss (57.33% vs 41.22%, P < 0.05), and β-catenin nuclear staining (53.45% vs 27.91%, P < 0.01) in follow-up samples. In addition, nonresponders exhibited lower recovery of intact PTEN and PAX2, along with higher β-catenin aberrancy in cases initially showing normal β-catenin levels. We conclude that persistent aberrant PTEN and PAX2 expression, coupled with emerging aberrant β-catenin in follow-ups, indicates a greater likelihood of treatment failure. Conversely, the absence of these aberrations suggests successful progestin therapy. Our findings highlight the utility of this 3-marker panel in assessing residual disease status and predicting progestin treatment outcomes, thus offering critical insights for patient management.

β-catenin, PAX2, and PTEN Aberrancy Across the Spectrum of Endometrioid Ovarian Lesions

Endometriosis is a common condition, with the ovary being the most common anatomic site. Endometriosis-particularly in the ovary-is associated with a risk of malignant progression, with a histologic spectrum of lesions from benign to malignant. Recently, a panel of 3 markers consisting of β-catenin, PAX2, and PTEN has been described as a potentially useful diagnostic adjunct in the diagnosis of intrauterine endometrioid neoplasia, where aberrancy for one or more of the markers is strongly associated with neoplasia. Here, we applied the panel to ovarian endometrioid lesions, including endometriosis, endometriosis with flat cytologic atypia, endometrioid borderline tumors, and endometrioid adenocarcinoma (n=85 cases in total). The incidence of aberrancy for the 3 markers increased along this putative neoplastic spectrum, arguing for a role of each of the markers in the neoplastic transformation of ovarian endometriosis. Just 1/32 (3%) of cases of nonatypical endometriosis was marker-aberrant, and this case was aberrant only for PAX2. One of 5 cases (20%) of endometriosis with atypia was marker-aberrant (both PAX2 and PTEN), supporting prior findings that some cases of flat atypia may represent bona fide precursor lesions. Of 19 endometrioid borderline tumors, 10 (53%) were aberrant for one or more markers, with PAX2 being the most frequently aberrant. Of 29 endometrioid adenocarcinomas, 28 (96.6%) were aberrant for at least 1 marker, with PAX2 again the most frequently aberrant. Patterns of aberrancy were well-preserved in areas of nonatypical endometriosis adjacent to borderline tumor or adenocarcinoma, supporting a biological origin in a common marker-aberrant precursor. The findings show that the biomarker panel could be of some diagnostic utility in the characterization of ovarian endometrioid neoplasia, such as in the diagnosis of endometrioid borderline tumor, distinguishing endometrioid from nonendometrioid lesions, or in identifying other types of early precursors at a higher risk of malignant transformation.

Unraveling the Dynamics of Estrogen and Progesterone Signaling in the Endometrium: An Overview

The endometrium is crucial for the perpetuation of human species. It is a complex and dynamic tissue lining the inner wall of the uterus, regulated throughout a woman's life based on estrogen and progesterone fluctuations. During each menstrual cycle, this multicellular tissue undergoes cyclical changes, including regeneration, differentiation in order to allow egg implantation and embryo development, or shedding of the functional layer in the absence of pregnancy. The biology of the endometrium relies on paracrine interactions between epithelial and stromal cells involving complex signaling pathways that are modulated by the variations of estrogen and progesterone levels across the menstrual cycle. Understanding the complexity of estrogen and progesterone receptor signaling will help elucidate the mechanisms underlying normal reproductive physiology and provide fundamental knowledge contributing to a better understanding of the consequences of hormonal imbalances on gynecological conditions and tumorigenesis. In this narrative review, we delve into the physiology of the endometrium, encompassing the complex signaling pathways of estrogen and progesterone.

Diagnostic Value and Molecular Function of MicroRNAs in Endometrial Diseases: A Systematic Review

The human endometrium experiences significant cyclic morphological and biochemical changes throughout the menstrual cycle to prepare for embryo implantation. These processes are meticulously regulated by ovarian steroids and various locally expressed genes, encompassing inflammatory reactions, apoptosis, cell proliferation, angiogenesis, differentiation (tissue formation), and tissue remodeling. MicroRNAs (miRNAs) have been recognized as crucial regulators of gene expression, with their altered expression being linked to the onset and progression of various disorders, including cancer. This review examines the expression of miRNAs in the endometrium and their potential regulatory roles under pathological conditions such as endometriosis, recurrent implantation failure and endometrial cancer. Given miRNAs' critical role in maintaining gene expression stability, understanding the regulatory mechanisms of endometrial miRNAs and identifying their specific target genes could pave the way for developing preventive and therapeutic strategies targeting specific genes associated with these reproductive disorders.

Nuclear β-Catenin Expression in the Context of Abnormal p53 Expression Indicates a Nonserous Histotype in Endometrial Carcinoma

The interobserver reproducibility is poor for histotyping within the p53-abnormal molecular category of endometrial carcinomas (ECs); therefore, biomarkers that improve histologic classification are useful. β-catenin has been proposed to have prognostic significance in specific clinicopathologic and molecular contexts. The diagnostic utility for β-catenin expression patterns in determining the histotype of p53-abnormal ECs has not been well studied. We identified ECs molecularly classified as "p53-abnormal." The p53-abnormal classification was assigned when (1) no POLE exonuclease domain hotspot mutations identified, (2) mismatch-repair protein expression was retained, and (3) abnormal p53 expression (null or overexpression) was present. Morphology was re-reviewed and β-catenin immunohistochemistry was scored as abnormal (nuclear) or normal (membranous, non-nuclear). Eighty ECs were identified in the "p53-abnormal" category; 27 (33.75%) were uterine serous carcinomas, and 53 were of nonserous histotype: 28 uterine carcinosarcomas (35%), 16 endometrioid carcinomas (20%), 2 clear cell carcinomas (2.5%), and 7 high-grade EC with ambiguous morphology (8.75%). All 27 uterine serous carcinomas demonstrated membranous β-catenin staining. Of the 53 nonserous ECs, 11 (21%) showed abnormal β-catenin expression: 6 endometrioid carcinomas, 4 uterine carcinosarcoma, and 1 high-grade EC with ambiguous morphology. The specificity of abnormal β-catenin expression for nonserous EC is high (100%) but the sensitivity is low (21%) with positive and negative predictive values of 100% and 60%, respectively. Our data shows that abnormal β-catenin expression in the context of p53-abnormal EC is highly specific, but not sensitive, for nonserous ECs and may be of value as part of a panel in classifying high-grade EC, particularly to exclude uterine serous carcinoma when nuclear staining is present.

Utility of a PAX2, PTEN, and β-catenin Panel in the Diagnosis of Atypical Hyperplasia/Endometrioid Intraepithelial Neoplasia in Endometrial Polyps

The diagnosis of atypical hyperplasia/endometrioid intraepithelial neoplasm (AH/EIN) within endometrial polyps (EMPs) often poses a diagnostic conundrum. Our previous studies demonstrated that a panel of immunohistochemical (IHC) markers consisting of PAX2, PTEN, and β-catenin can be effectively utilized for the identification of AH/EIN. A total of 105 AH/EIN within EMP were analyzed using the 3-marker panel. We also evaluated these cases for the presence of morules. Benign EMP (n=90) and AH/EIN unassociated with polyp (n=111) served as controls. Aberrant expression of PAX2, PTEN, or β-catenin was observed in AH/EIN in EMP in 64.8%, 39.0%, and 61.9% of cases, respectively. At least 1 IHC marker was abnormal in 92.4% of cases. Overall, 60% of AH/EIN in EMP demonstrated abnormal results for≥2 IHC markers. The prevalence of PAX2 aberrancy was significantly lower in AH/EIN in EMP than in nonpolyp AH/EIN (64.8% vs. 81.1%, P =0.007), but higher than in benign EMP (64.8% vs. 14.4%, P <0.00001). The prevalence of β-catenin aberrancy was significantly higher in AH/EIN in EMP than in nonpolyp AH/EIN (61.9% vs. 47.7%, P =0.037). All control benign EMP demonstrated normal expression of PTEN and β-catenin. Morules were present in 38.1% of AH/EIN in EMP versus 24.3% in nonpolyp AH/EIN, and absent in benign EMP. A strong positive association was found between β-catenin and morules (Φ=0.64). Overall, 90% cases of atypical polypoid adenomyoma (n=6) and mucinous papillary proliferation (n=4) showed IHC marker aberrancy. In conclusion, the 3-marker IHC panel (PAX2, PTEN, and β-catenin) is (1) a useful tool in the diagnosis of AH/EIN in EMP; (2) PAX2 loss should be interpreted with caution and in combination with morphology and other markers.

β-catenin, Pax2, and Pten Panel Identifies Precancers Among Histologically Subdiagnostic Endometrial Lesions

Despite refinements in histologic criteria for the diagnosis of endometrioid precancers, many challenging cases are encountered in daily practice, creating diagnostic uncertainty and suboptimal patient management. Recently, an immunohistochemical 3-marker panel consisting of β-catenin, Pax2, and Pten was identified as a useful diagnostic adjunct. However, previous studies focused either on cancers or diagnostically unambiguous precancers, leaving questions about the applicability and utility of the panel in endometria with architectural features near or below the threshold of accepted histologic criteria for endometrioid precancers. Here, in a retrospective study of 90 patients, we evaluated the performance of the 3-marker panel. Notably, the panel detected a subset of disordered proliferative endometria (8/44, 18%), nonatypical hyperplasias (19/40, 48%), and cases with ambiguous features (3/6, 50%) with aberrancy for ≥1 markers. Marker-aberrant cases were more likely to progress to endometrioid precancer or cancer ( P =0.0002). Patterns of marker aberrancy in the index and progressor cases from individual patients provided evidence for origin in a common precursor, and next-generation sequencing of the progressor cases rationalized marker aberrancy for β-catenin and Pten. The results unequivocally demonstrate that some lesions that do not approach current histologic thresholds are bona fide neoplastic precursors with clinically-relevant driver events that can be detected by the 3-marker panel. The findings provide further validation for the diagnostic utility of the panel in clinical practice and its application in difficult or ambiguous cases.

FOXA2 suppresses endometrial carcinogenesis and epithelial-mesenchymal transition by regulating enhancer activity

FOXA2 encodes a transcription factor mutated in 10% of endometrial cancers (ECs), with a higher mutation rate in aggressive variants. FOXA2 has essential roles in embryonic and uterine development. However, FOXA2’s role in EC is incompletely understood. Functional investigations using human and mouse EC cell lines revealed that FOXA2 controls endometrial epithelial gene expression programs regulating cell proliferation, adhesion, and endometrial-epithelial transition. In live animals, conditional inactivation of Foxa2 or Pten alone in endometrial epithelium did not result in ECs, but simultaneous inactivation of both genes resulted in lethal ECs with complete penetrance, establishing potent synergism between Foxa2 and PI3K signaling. Studies in tumor-derived cell lines and organoids highlighted additional invasion and cell growth phenotypes associated with malignant transformation and identified key mediators, including Myc and Cdh1. Transcriptome and cistrome analyses revealed that FOXA2 broadly controls gene expression programs through modification of enhancer activity in addition to regulating specific target genes, rationalizing its tumor suppressor functions. By integrating results from our cell lines, organoids, animal models, and patient data, our findings demonstrated that FOXA2 is an endometrial tumor suppressor associated with aggressive disease and with shared commonalities among its roles in endometrial function and carcinogenesis.

Histopathologic diagnosis of endometrial precancers: Updates and future directions

Early detection of endometrial cancer, especially its precancers, remains a critical and evolving issue in patient management and the quest to decrease mortality due to endometrial cancer. Due to many factors such as specimen fragmentation, the confounding influence of endogenous or exogenous hormones, and variable or overlapping histologic features, identification of bona fide endometrial precancers and their reliable discrimination from benign mimics remains one of the most challenging areas in diagnostic pathology. At the same time, the diagnosis of endometrial precancer, or the presence of suspicious but subdiagnostic features in an endometrial biopsy, can lead to long clinical follow-up with multiple patient visits and serial endometrial sampling, emphasizing the need for accurate diagnosis. Our understanding of endometrial precancers and their diagnosis has improved due to systematic investigations into morphologic criteria, the molecular genetics of endometrial cancer and their precursors, the validation of novel biomarkers and their use in panels, and more recent methods such digital image analysis. Although precancers for both endometrioid and non-endometrioid carcinomas will be reviewed, emphasis will be placed on the former. We review these advances and their relevance to the histopathologic diagnosis of endometrial precancers, and the recently updated 2020 World Health Organization (WHO) Classification of Female Genital Tumors.

Nuclear Beta-Catenin Expression in Endometrioid Intraepithelial Neoplasia (Atypical Hyperplasia) Does Not Predict Carcinoma on Subsequent Hysterectomy

Beta-catenin (BC) mutations are associated with a high risk of recurrence in otherwise low-grade, early-stage uterine endometrioid adenocarcinomas. Recent literature suggests nuclear BC expression by immunohistochemistry is highly sensitive and specific for BC mutations. The significance of BC expression in endometrioid intraepithelial neoplasia (EIN/atypical hyperplasia) and its relationship to altered differentiation patterns in EIN has yet to be fully explored. Cases meeting current diagnostic criteria for EIN based on H&E examination were obtained from 2 institutions (years 1999-2014). Patterns of altered differentiation (eg, tubal, squamous morular metaplasia, mucinous, secretory) were noted. Representative blocks were stained for BC, and expression patterns recorded. Follow-up and demographic data was obtained from the electronic medical record. Ninety-six cases were included (84 biopsies, 12 hysterectomies). BC nuclear expression was identified in 41 cases (42.7%), with 33 of 41 demonstrating foci of nonmorular BC staining. BC staining in any component of EIN was not significantly associated with the presence of carcinoma on subsequent hysterectomy (P=0.79). When restricting to nonmorular BC, the results were the same (P=0.56). Cases with tubal differentiation were significantly less likely to demonstrate nonmorular BC than cases with no specific pattern of differentiation (P<0.01). EIN frequently demonstrates BC nuclear positivity, especially in cases without tubal differentiation. BC nuclear expression in EIN does not appear to be associated with an increased likelihood of carcinoma on subsequent hysterectomy. Our results do not support routine use of BC immunohistochemistry as a prognostic biomarker in cases of EIN.

Serial genomic analysis of endometrium supports the existence of histologically indistinct endometrial cancer precursors

The endometrium is unique as an accessible anatomic location that can be repeatedly biopsied and where diagnostic biopsies do not extirpate neoplastic lesions. We exploited these features to retrospectively characterize serial genomic alterations along the precancer/cancer continuum in individual women. Cases were selected based on (1) endometrial cancer diagnosis/hysterectomy and (2) preceding serial endometrial biopsies including for some patients an early biopsy before a precancer histologic diagnosis. A comprehensive panel was designed for endometrial cancer genes. Formalin‐fixed, paraffin‐embedded specimens for each cancer, preceding biopsies, and matched germline samples were subjected to barcoded high‐throughput sequencing to identify mutations and track their origin and allelic frequency progression. In total, 92 samples from 21 patients were analyzed, providing an opportunity for new insights into early endometrial cancer progression. Definitive invasive endometrial cancers exhibited expected mutational spectra, and canonical driver mutations were detectable in preceding biopsies. Notably, ≥1 cancer mutations were detected prior to the histopathologic diagnosis of an endometrial precancer in the majority of patients. In 18/21 cases, ≥1 mutations were confirmed by abnormal protein levels or subcellular localization by immunohistochemistry, confirming genomic data and providing unique views of histologic correlates. In 19 control endometria, mutation counts were lower, with a lack of canonical endometrial cancer hotspot mutations. Our study documents the existence of endometrial lesions that are histologically indistinct but are bona fide endometrial cancer precursors. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Identification of pAKT as a pharmacodynamic marker for MER kinase in human melanoma G361 cells

Background

The MER signaling pathway represents an attractive therapeutic target for human cancers. Growth arrest–specific protein 6 (GAS6)–induced MER phosphorylation is often unstable and difficult to detect without pervanadate pretreatment in human cancer cells, posing a challenge for the development of selective MER kinase inhibitors. Here, we identified phosphorylated AKT (pAKT) as a specific pharmacodynamic marker for MER kinase inhibitors in human melanoma G361 cells.

Methods

The expression of MER, TYRO3, and AXL were profiled among multiple human cancer cells. To determine whether they play a role in the activation of pAKT, MER and TYRO3 were selectively depleted by small, interfering RNA knockdown. In addition, using AKT phosphorylation as a readout, a high-throughput cell-based assay was established in G361 cells for evaluation of the potency of potential inhibitors of MER pathway activation.

Results

We demonstrated that high levels of MER and TYRO3, but not AXL, were expressed in G361 cells. In these cells, pAKT was induced by GAS6 treatment, which could be reversed by AXL/MER inhibitors. We showed that GAS6-induced pAKT is only dependent on MER kinase, but not TYRO3, in G361 cells. Furthermore, we observed a correlation in potency between inhibition of pAKT in G361 cells and pMER in MER-overexpressing Ba/F3 cells by these inhibitors.

Conclusions

In summary, we have demonstrated that GAS6-induced pAKT is a possible pharmacodynamic marker for the inhibition of MER kinase, and we have successfully developed a cell-based functional assay for screening small-molecule inhibitors of MER kinase for potential therapeutic utility in treating GAS6/MER-deregulated human cancers.

Fbxw7 is a driver of uterine carcinosarcoma by promoting epithelial-mesenchymal transition

Uterine carcinosarcoma (UCS) is an aggressive endometrial cancer variant distinguished from endometrial adenocarcinoma (EC) by admixed malignant epithelial and mesenchymal components (carcinoma and sarcoma). The molecular events underlying UCS are enigmatic, as cancer gene mutations are generally shared among UCS/EC. We take advantage of genetic approaches in mice to show that inactivation of Fbxw7 and Pten results in UCS through spontaneous acquisition of mutations in a third gene (Tp53), arguing for strong biological selection and synergism in UCS. We used this UCS model including tumor-derived cell lines to show that Fbxw7 loss drives epithelial–mesenchymal transition, explaining Fbxw7’s role in UCS. This model system argues that simultaneous genetic defects in 3 distinct pathways (Fbxw7, Pten/PI3K, Tp53) converge in UCS genesis.

Uterine carcinosarcoma is an aggressive variant of endometrial carcinoma characterized by unusual histologic features including discrete malignant epithelial and mesenchymal components (carcinoma and sarcoma). Recent studies have confirmed a monoclonal origin, and comprehensive genomic characterizations have identified mutations such as Tp53 and Pten. However, the biological origins and specific combination of driver events underpinning uterine carcinosarcoma have remained mysterious. Here, we explored the role of the tumor suppressor Fbxw7 in endometrial cancer through defined genetic model systems. Inactivation of Fbxw7 and Pten resulted in the formation of precancerous lesions (endometrioid intraepithelial neoplasia) and well-differentiated endometrioid adenocarcinomas. Surprisingly, all adenocarcinomas eventually developed into definitive uterine carcinosarcomas with carcinomatous and sarcomatous elements including heterologous differentiation, yielding a faithful genetically engineered model of this cancer type. Genomic analysis showed that most tumors spontaneously acquired Trp53 mutations, pointing to a triad of pathways (p53, PI3K, and Fbxw7) as the critical combination underpinning uterine carcinosarcoma, and to Fbxw7 as a key driver of this enigmatic endometrial cancer type. Lineage tracing provided formal genetic proof that the uterine carcinosarcoma cell of origin is an endometrial epithelial cell that subsequently undergoes a prominent epithelial–mesenchymal transition underlying the attainment of a highly invasive phenotype specifically driven by Fbxw7.

Nuclear expression of β-catenin in endometrial hyperplasia as marker of premalignancy

We aimed to assess (1)-whether nuclear β-catenin is a marker of endometrial precancer, and (2)-the diagnostic accuracy of β-catenin immunohistochemistry in the differential diagnosis between benign and premalignant endometrial hyperplasia (EH), defining criteria for its use. Electronic databases were searched for studies evaluating β-catenin immunohistochemistry in normal endometrium (NE), benign and/or premalignant EH, and endometrioid carcinoma (EC). Odds ratio (OR; p < 0.05), sensitivity, specificity, diagnostic OR (DOR), positive and negative likelihood ratios (LR+, LR-) were calculated. Subgroup analyses were based on the classification system used (WHO or EIN) and criteria to define aberrant β-catenin expression (only nuclear or cytoplasmic/nuclear). Twelve studies with 1510 specimens were included. Nuclear β-catenin rate significantly increased from NE to benign EH (OR = 26.01; p = 0.0002, only in WHO subgroup), and from benign EH to premalignant EH (OR = 3.89; p = 0.0002; more markedly in EIN subgroup), but not from premalignant EH to EC (OR = 0.78; p = 0.29). Nuclear β-catenin accuracy was very low in WHO subgroup (sensitivity = 0.40, specificity = 0.76, LR+ = 1.85, LR- = 0.72; DOR = 2.89) and moderate in EIN subgroup (sensitivity = 0.19, specificity = 1.00, LR+ = 14.80, LR- = 0.83; DOR = 18.14). Cytoplasmic/nuclear β-catenin accuracy was absent in WHO subgroup (sensitivity = 0.45, specificity = 0.54, LR+ = 1.01, LR- = 1.01; DOR = 0.99) and low in EIN subgroup (sensitivity = 0.57, specificity = 0.86, LR+ = 3.63, LR- = 0.51; DOR = 8.30). Considering nuclear expression and using EIN system, β-catenin immunohistochemistry might be reliable as rule-in test for diagnosis of endometrial precancer, with perfect specificity and moderate overall accuracy.

Identification of Potential Biomarkers with Diagnostic Value in Pituitary Adenomas Using Prediction Analysis for Microarrays Method

Pituitary adenomas are the most common intrasellar tumors. Patients should be identified at an early stage so that effective treatment can be implemented. The study aims at detecting the potential biomarkers with diagnostic value of pituitary adenomas. Using a total of seven gene expression profiles (GEPs) of the datasets from the Gene Expression Omnibus (GEO) database, we first screened 1980 significant differentially expressed genes (DEGs). Then, we employed the prediction analysis for microarray (PAM) algorithm to identify 340 significant DEGs able to differ pituitary tumor from normal samples, which include 208 upregulated DEGs and 132 downregulated DEGs. DAVID database was used to carry out the enrichment analysis on Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) pathways. We found that upregulated candidates were enriched in protein folding and metabolic pathways. Downregulated DEGs saw a significant enrichment in insulin receptor signaling pathway and hedgehog signaling pathway. Based on the protein-protein interaction (PPI) network as well as module analysis, we determined ten hub genes including PHLPP, ENO2, ACTR1A, EHHADH, EHMT2, FOXO1, DLD, CCT2, CSNK1D, and CETN2 that could be potential biomarkers with diagnostic value in pituitary adenomas. In conclusion, the study contributes to reliable and potential molecular biomarkers with diagnostic value. Moreover, these potential biomarkers may be used for prognosis and new therapeutic targets for the pituitary adenomas.

Genomic Comparison of Endometrioid Endometrial Carcinoma and Its Precancerous Lesions in Chinese Patients by High-Depth Next Generation Sequencing

Endometrial intraepithelial neoplasia (EIN), also known as endometrial atypical hyperplasia (EAH) is believed to be the precursor lesion of endometrioid endometrial carcinoma (EEC). Many genetic factors play important roles in the process of carcinogenesis, however, the key genetic alterations from dysplasia to endometrial cancer remains poorly understood. Germline mutations in Lynch syndrome genes are associated with hereditary endometrial carcinoma. The role of other cancer susceptibility genes is unclear. The aim of this study was to investigate the genomic alterations of premalignant endometrial lesion and EEC, and to determine the prevalence of cancer predisposition gene mutations in an unselected endometrial carcinoma patient cohort. Here, we applied a comprehensive cancer gene panel (363 cancer-related genes) to capture the exomes of cancer-related genes. Samples were collected from 79 patients with EEC and 36 patients with EIN. Our results demonstrate that EIN harbors most of the driver events reported in EEC and for the first time we reported a high frequency of the amplification of VEGFB gene in endometrial cancer. Moreover, we identified four novel candidate cancer-associated genes (CTCF, ARHGAP35, NF1, and KDR) which may be crucial in the carcinogenesis of EEC. In addition, we identified 2 patients who had a deleterious germline mutation in Lynch syndrome genes (MLH1 and MLH2), and another 8 patients harbored germline mutations of 6 non-Lynch syndrome genes (MUTYH, GALNT12, POLE, MPL, ATM, and ERCC4) which may be associated with endometrial cancer. Larger series will have to be investigated to assess the risks and the proportion of endometrial cancers attributable to other genes.