Endometrial Carcinogenesis Research Articles

Estrogen-ER\u03b1 signaling and DNA hypomethylation co-regulate expression of stem cell protein PIWIL1 in ER\u03b1-positive endometrial cancer cells

BackgroundWe previously identified PIWIL1 as an oncogene involved in endometrial carcinogenesis. However, the mechanism of Piwil1 mediated regulation of tumorigenesis remains poorly understood.MethodsThe expression levels of target genes in endometrial cancer cells were detected by quantitative reverse transcription-PCR (RT-qPCR) and western blotting. Up- or down-regulation of ERα or PIWIL1 was achieved by transient transfection with expressing plasmids or short hairpin RNA (shRNA). Dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) were used to demonstrate the ERα bound to the half estrogen response element (half-ERE) located in PIWIL1 promoter. The expression of PIWIL1 and ERα in endometrial carcinoma tissues were investigated using immunohistochemistry and RT-qPCR. The proliferation ability of cancer cells were evaluated by MTT. Methylation status of the PIWIL1 promoter was detected by bisulfite sequencing PCR (BSP).ResultsIn the present study, we found that PIWIL1 mediated E2-stimulated cancer cell proliferation. In ERα-positive endometrial cancer cells, we demonstrated that estrogen-ERα signaling significantly up-regulated the expression of PIWIL1, which was mediated by binding of the ERα onto the PIWIL1 promoter. Furthermore, we found that a half-ERE in the PIWIL1 promoter was essential for ERα binding. The PIWIL1 promoter was hypomethylated in ERα-positive endometrial cancer cells. Treatment with 5-aza-deoxycytidine (5-aza-dC) could up-regulate PIWIL1 expression.ConclusionsThese findings uncover a novel molecular mechanism by which estrogen-ERα signaling and DNA hypomethylation co-regulate PIWIL1 expression. These findings provide novel insights into the hormonal regulation of PIWIL1 in endometrial cancer and the PIWIL1’s role in estrogen-stimulated endometrial carcinogenesis.D4vML-nYL5hyvYVspqxCmiVideo . (MP4 41319 kb)

Expression of anti-apoptotic protein survivin in human endometrial carcinoma: Clinical and pathological associations as a separate factor and in combination with concomitant PTEN and p53 expression.

Endometrial carcinoma is one of the most common types of gynecological cancer. A total of 99 cases of primary endometrial carcinoma were investigated for survivin expression by immunohistochemistry. Furthermore, the association between concomitant survivin, PTEN and p53 expression, and clinicopathological parameters was examined. Immunopositivity for survivin was identified in 88% of cases. Concomitant survivin, PTEN and p53 expression (staining scores and intensity) was observed in 60% of endometrial adenocarcinomas. A significant association was identified between the sum of staining intensity and scores of survivin immunopositive cells, and patient age (P=0.028), histological grade (P<0.001), clinical stage (P=0.018) and fallopian tube and/or ovarian invasion (P=0.039). A negative tendency for correlation was observed between surivin and PTEN immunostaining scores (P=0.062; ρ=−0.238). Specimens with high scores of survivin expression tended to show decreased scores of PTEN immunostaining, and vice versa. However, in circumstances with an increased co-expression of survivin and PTEN, a statistically significant association with histological types was observed (P=0.020). A statistically significant positive correlation was identified between survivin and p53 sum co-expression (P=0.008; ρ=0.300). Furthermore, a significant association was identified between survivin and p53 concomitant sum expression and age of patients (P=0.001), histological type (P=0.020), clinical stage (P=0.037), histological differentiation (P=0.001) and presence of fallopian tube and/or ovarian invasion (P=0.026). The present findings suggested that survivin may be an indicator of unfavorable outcome in older patients with endometrial carcinoma, in specific circumstances that are dependent on different concomitant genetic alterations and different combinations of molecular signaling pathways. Increased expression levels of survivin and PTEN may serve a role in the development of more aggressive endometrial carcinoma during their interaction. In addition, protein expression levels of survivin and p53 are positively correlated and may share a common molecular pathway to promote endometrial carcinogenesis. These findings provided evidence that survivin and p53 combined may be useful markers for the prediction of tumor behavior and prognosis.

ASH2L is involved in promotion of endometrial cancer progression via upregulation of PAX2 transcription.

Absent, small or homeotic 2‐like protein (ASH2L) is a core component of a multimeric histone methyltransferase complex that is involved in the maintenance of active transcription, participating in several cancers, however the biological function and molecular mechanism of ASH2L in endometrial cancer (ECa) are largely unknown. Endometrial cancer is a common malignant tumor in women and the incidence of this cancer is on the rise. Estrogen‐ERα signaling, as an oncogenic pathway, plays a crucial role in endometrial carcinogenesis. Therefore, further exploration of the molecular mechanisms around ERα‐mediated gene transcription in ECa would be helpful to the understanding of tumor development and to finding a new therapeutic target for ECa. Here, our study demonstrated that ASH2L was highly expressed in ECa samples, and higher expression of ASH2L was positively correlated with a poor prognosis. Moreover, we identified that ASH2L associated with ERα and that knockdown of ASH2L resulted in decreased expression of a subset of the estrogen‐induced target genes, including paired box 2 (PAX2), an oncogenic gene in ECa. ASH2L was recruited to cis‐regulatory elements in PAX2, thereby altering histone H3K4me3 and H3K27me3 levels, to enhance ERα‐mediated transactivation. Finally, depletion of ASH2L suppressed endometrial cancer cell proliferation and migration. Our findings suggest that ASH2L participates in the promotion of ECa progression, if not totally at least partially, via upregulation of PAX2 transcription.

Clinical relevance of ARF/ARL family genes and oncogenic function of ARL4C in endometrial cancer

Members of ADP-ribosylation factor (ARF)/ARF-like protein (ARL) family regulate malignant phenotype of cancer cells. The present study aims to investigate the clinical relevance of ARF/ARL family members in endometrial cancer. We report that several ARF/ARL family genes serve as prognostic biomarkers for endometrial cancer. Through a combination of TCGA database and immunohistochemistry analysis, we revealed that ARL4C, a member of ARL family, was overexpressed in endometrial cancer and might function as an oncogene in endometrial carcinogenesis. Gene set enrichment analysis (GSEA) and functional studies demonstrated that cell cycle and cell adhesion pathways were the potential mechanism of ARL4C in promoting endometrial cancer cell proliferation, migration and invasion. Moreover, we also observed the involvement of ARL4C in metformin-inhibited cellular proliferation of endometrial cancer. Collectively, knowledge of the expression and function of ARF/ARL family genes could provide a potential therapeutic strategy for endometrial cancer.

Estrogen receptor expression in complex and/or atypical endometrial hyperplasia and endometrial adenocarcinoma

Endometrial cancer affects approximately 142,000 women worldwide each year, and an estimated 42,000 women die from this cancer. Endometrial carcinoma is categorised into type I endometrial carcinoma and type II endometrial carcinoma. Endometrial hyperplasia and unopposed estrogenic stimulation are a significant risk factor in endometrial carcinogenesis. Type II carcinomas especially serous carcinomas are known to develop in the atrophic endometrium in an older age group and are not associated with hyperestrogenism. Early stage and well differentiated tumors are primarily estrogen and progesterone positive. Expression of estrogen receptors correlates with low tumor grade, low recurrence rate and higher survival. Whereas absence of estrogen receptor expression is associated with a worse prognosis

Endometrial cancer prevention in high-risk women.

Endometrial cancer (EC) is the most common gynaecological malignancy, and its incidence is rising alongside the growing prevalence of obesity. Effective risk-reducing interventions hijacking the key mechanisms driving endometrial carcinogenesis may affect EC diagnoses if aimed at those at greatest risk. An understanding of the key risk factors and their role in tumourigenesis is critical in developing such prevention strategies. In this review, we summarise the major risk factors for EC and the evidence for available risk-reducing interventions in high-risk women. We suggest potential prevention strategies and make a case for the need for risk prediction models that identify specific groups of women at a particularly high risk of EC for whom risk-reducing interventions are likely to have a significant impact.

ASH2L Acts As a Co-Activator of ERα to Participate in the Promotion of Endometrial Cancer Progression

Background: Estrogen-ERα signaling is an oncogenic pathway plays a crucial role in endometrial carcinogenesis. However, modulation of ERα action in Endometrial cancer (ECa) remains to be elusive. Absent, small or homeotic 2-like protein (ASH2L) is a core component of multimeric histone methyltransferase complex, which is involved in maintenance the active chromatin states. What is the function of ASH2L on modulation of E2-ERα induced transactivation in ECa needs to be further understood. Methods: Immunoprecipitation, Immunofluorescence assay, luciferase assay, quantitative RT-PCR, and western blot were performed to investigate how ASH2L regulates the transcriptional activity of ERα. ChIP assay was performed to determine the recruitment of ASH2L to cis-regulatory elements. Lentiviral infection, colony formation, transwell experiments, and mice xenograft experiments were performed to evaluate the function of ASH2L on cell growth and migration. Findings: Our study demonstrated that ASH2L was highly expressed in ECa samples, and the higher expression of ASH2L is positively correlated with the poor prognosis. ASH2L associates with ERα and upregulates ERα-induced transactivation in ECa cells. ASH2L is recruited to cis -regulatory elements at ERα regulated gene, thereby modulating histone H3K4me3 and H3K27me3 levels, to maintain the active transcription. ASH2L depletion suppresses cell growth and migration in ECa. Interpretation: Our findings suggest that ASH2L associates with ERα to be involved in regulation of ERα-induced transactivation. ASH2L participates in promotion of ECa progression. Funding Statement: This study was supported by National Natural Science Foundation of China [31871286 for Yue Zhao, 81872015 for Chunyu Wang, 31701102 for Shengli Wang, 81702800 for Renlong Zou, 81502438 for Tingting Zhou, 81902889 for Wensu Liu]. Declaration of Interests: The authors declare no conflict of interests. Ethics Approval Statement: All procedures of animal experiments have been carried out in compliance with ethical regulations approved by the Animal Ethics Committee of China Medical University. This study was approved by the Ethics Committee of the Medical Faculty of the China Medical University.

Dietary inflammatory index, risk and survival among women with endometrial cancer.

Chronic inflammation has been implicated in endometrial carcinogenesis yet the impact of potentially modifiable exposures that might affect inflammation, like diet, has been understudied. This study examined the association between the dietary inflammatory index (DII®), a literature-derived tool to assess the inflammatory potential of diet, and risk of developing, and survival after a diagnosis of endometrial cancer (EC). This study included data from 1,287 women with EC and 1,435 population controls who participated in the Australian National Endometrial Cancer Study. Energy-adjusted DII (E-DII) scores were calculated from pre-diagnostic dietary intake obtained using a semi-quantitative food frequency questionnaire. Logistic regression was used to assess the association between E-DII scores and risk of EC and proportional-hazards models were used for survival analyses. Higher E-DII scores, reflecting a more pro-inflammatory diet, were not associated with risk of EC [adjusted odds ratio (OR) 0.98, 95% CI 0.77-1.24, p-trend = 0.7]. However, in stratified analyses, higher E-DII scores were associated with increased risk of EC among very obese (BMI 35 + kg/m2) women (OR 1.60, 95% CI 0.80-3.21, p-trend = 0.049, p-interaction = 0.045). After a median follow-up of 7.2years there were 160 deaths, of which 110 (69%) were from EC. We found no association between E-DII score and survival. Greater inflammatory potential of pre-diagnostic diet was not associated with EC risk or survival. Secondary stratified analysis suggested greater inflammatory potential may be associated with EC risk in very obese women.

SIX1 Regulates Aberrant Endometrial Epithelial Cell Differentiation and Cancer Latency Following Developmental Estrogenic Chemical Exposure.

Early-life exposure to estrogenic chemicals can increase cancer risk, likely by disrupting normal patterns of cellular differentiation. Female mice exposed neonatally to the synthetic estrogen diethylstilbestrol (DES) develop metaplastic and neoplastic uterine changes as adults. Abnormal endometrial glands express the oncofetal protein sine oculis homeobox 1 (SIX1) and contain cells with basal [cytokeratin (CK)14+/18-] and poorly differentiated features (CK14+/18+), strongly associating SIX1 with aberrant differentiation and cancer. Here, we tested whether SIX1 expression is necessary for abnormal endometrial differentiation and DES-induced carcinogenesis by using Pgr-cre to generate conditional knockout mice lacking uterine Six1 (Six1 d/d). Interestingly, corn oil (CO) vehicle-treated Six1 d/d mice develop focal endometrial glandular dysplasia and features of carcinoma in situ as compared with CO wild-type Six1 (Six1 +/+) mice. Furthermore, Six1 d/d mice neonatally exposed to DES had a 42% higher incidence of endometrial cancer relative to DES Six1 +/+ mice. Although DES Six1 d/d mice had >10-fold fewer CK14+/18- basal cells within the uterine horns as compared with DES Six1 +/+ mice, the appearance of CK14+/18+ cells remained a feature of neoplastic lesions. These findings suggest that SIX1 is required for normal endometrial epithelial differentiation, CK14+/18+ cells act as a cancer progenitor population, and SIX1 delays DES-induced endometrial carcinogenesis by promoting basal differentiation of CK14+/18+ cells. In human endometrial biopsies, 35% of malignancies showed CK14+/18+ expression, which positively correlated with tumor stage and grade and was not present in normal endometrium. IMPLICATIONS: Aberrant epithelial differentiation is a key feature in both the DES mouse model of endometrial cancer and human endometrial cancer. The association of CK14+/18+ cells with human endometrial cancer provides a novel cancer biomarker and could lead to new therapeutic strategies.

Prognostic molecular biomarkers in endometrial cancer: A review.

Background:Endometrial cancer (EC) is the fourth most common malignancy in women worldwide and the most common gynecological cancer in developed countries. The endometrioid subtype has an excellent prognosis with conventional treatment; however, recurrence reduces overall survival.Objective:Describe the most relevant evidence regarding selected potential molecular biomarkers that may predict overall survival (OS), relapse-free survival (RFS), and cancer-specific survival (CSS) in EC.Methods:An exhaustive search was performed in PUBMED with the search terms endometrial cancer, molecular biomarker, and survival. We selected original articles written in English about endometrial cancer, molecular biomarkers, and that included survival analysis published between January 2000 and December 2016.Results:Several molecular prognostic biomarkers have been studied in terms of survival and therapeutic response in women with endometrial cancer; hormone receptors, microRNAs, and other molecules have emerged as potentially useful biomarkers, including HER2, p21, HE4, PTEN, p27, ANCCA, and ANXA2.Conclusions:The use of biomarkers in the assessment of OS, RFS, and CSS requires large trials to expand our understanding of endometrial carcinogenesis. Several molecular markers are significantly associated with a high tumor grade and advanced clinical stage in EC and, therefore, could have additive effects when combined.

Quantitative next-generation sequencing-based analysis indicates progressive accumulation of microsatellite instability between atypical hyperplasia/endometrial intraepithelial neoplasia and paired endometrioid endometrial carcinoma

Atypical hyperplasia/endometrial intraepithelial neoplasia is an accepted precursor to endometrioid-type endometrial carcinoma. Mismatch repair-deficient endometrial carcinomas are also known to be a biologically and clinically distinct subset of tumors. However, the development of microsatellite instability in endometrial carcinogenesis has not yet been evaluated by novel next-generation sequencing-based methods. We examined 17 mismatch repair-deficient endometrioid endometrial carcinomas and their paired atypical hyperplasia/endometrial intraepithelial neoplasia precursors using a next-generation sequencing panel with quantitative microsatellite instability detection at 336 loci. Findings were compared to histological features, polymerase chain reaction-based microsatellite instability testing, immunohistochemical expression of mismatch repair proteins, and tumor mutational burden calculations. All 17 endometrial carcinomas and 8/17 atypical hyperplasia/endometrial intraepithelial neoplasia showed microsatellite instability by next-generation sequencing-based testing. Endometrial carcinoma specimens showed significantly more unstable microsatellite loci than paired atypical hyperplasia/endometrial intraepithelial neoplasia (mean: 40.0% vs 19.9 unstable loci, respectively). Out of nine microsatellite-stable atypical hyperplasia/endometrial intraepithelial neoplasia specimens, four showed mismatch repair loss by immunohistochemistry. All atypical hyperplasia/endometrial intraepithelial neoplasia and endometrial carcinoma specimens with microsatellite instability were also mismatch repair-deficient by immunohistochemistry. Tumor mutational burden was significantly greater in endometrial carcinoma than in paired atypical hyperplasia/endometrial intraepithelial neoplasia specimens, and tumor mutational burden was significantly correlated with percent unstable microsatellite loci. Paired atypical hyperplasia/endometrial intraepithelial neoplasia and endometrial carcinoma specimens show progressive accumulation of unstable microsatellite loci following loss of mismatch repair protein expression. Comprehensive next-generation sequencing-based testing of endometrial carcinomas offers new insights into endometrial carcinogenesis and opportunities for improved tumor surveillance, diagnosis, and management.

Endometrial cancer and obesity

Key content Of the 20 most common tumour types, endometrial cancer has the strongest association with obesity. Endometrial cancer should be considered in young, obese women with irregular or heavy menstrual bleeding. To reduce the risk of postoperative complications, surgery for endometrial cancer should be performed using minimal access techniques whenever possible. For women who are unfit for, or who decline, surgery, alternative treatments include progestins or radiotherapy, but these have lower efficacy and are associated with a higher risk of disease relapse. Obesity is associated with reduced overall survival following endometrial cancer because of increased cardiovascular mortality; it may also affect disease‐specific survival. Learning objectives To further understanding of the mechanisms through which obesity drives endometrial carcinogenesis. To improve understanding of the potential difficulties associated with the management of endometrial cancer in obese women. To increase knowledge of alternative treatment options for women who are unfit for, or who decline, standard endometrial cancer management. Ethical issues The number of young, premenopausal women with endometrial cancer is increasing – how should these women be managed? Should super‐obese women with endometrial cancer only be treated in cancer centres? After treating a woman's endometrial cancer, how should she be counselled her about her weight and cardiovascular disease risk?

Abstract 1733: Role of the SIX1 oncofetal protein in endometrial basal cell metaplasia and carcinogenesis following neonatal exposure to diethylstilbestrol

Abstract Early-life exposure to estrogenic chemicals can increase cancer risk, likely by disrupting normal patterns of cellular differentiation. In a model of this process, female mice exposed to the potent synthetic estrogen diethylstilbestrol (DES) on postnatal days 1-5 develop endometrial adenobasal carcinoma as adults. Neoplastic glands are comprised of abnormal populations of basal cells (cytokeratin (CK)14+), luminal cells (CK18+), and low numbers of "mixed” basal/luminal cells (CK14+/18+), all of which express the oncofetal protein sine oculis homeobox 1 (SIX1). We hypothesized that DES-induced SIX1 expression is necessary for aberrant endometrial differentiation patterns and carcinogenesis. To test this hypothesis, a conditional knockout model was generated in which floxed Six1 was excised in the uterus using progesterone receptor (Pgr) cre. The most prominent change in DES-exposed SIX1 knockout (DES-Six1d/d) mice was the absence of basal cells in the uterine horns. There was a greater than 10-fold decrease in CK14 labeling in the uterine horns of DES-Six1d/d mice compared to DES-exposed SIX1 wildtype (DES-Six1+/+) mice as determined by quantitative image analysis. However, DES-Six1d/d mice exhibited a 42% increase in cancer incidence compared to DES-Six1+/+ mice at 6 months of age (16/18 DES-Six1d/d vs. 7/15 DES-Six1+/+). Interestingly, mixed cells were still present in DES-Six1d/d mice. These findings demonstrate that SIX1 is a cellular differentiation factor necessary for DES-induced basal cells but not mixed cell development or cancer. Furthermore, these data suggest that DES-induced SIX1 expression decreases endometrial carcinogenesis by facilitating basal cell differentiation. Studies investigating the mixed cell population as a putative cancer progenitor cell population are ongoing. Interestingly, mixed cells were present in 35% (63/181) of malignant human endometrial tissue biopsies and in 0% (0/29) of normal endometrial tissue biopsies, suggesting that the DES mouse model has significant similarities to human endometrial cancer. Citation Format: Alisa A. Suen, Wendy N. Jefferson, Charles E. Wood, Anna C. Kenan, Carmen J. Williams. Role of the SIX1 oncofetal protein in endometrial basal cell metaplasia and carcinogenesis following neonatal exposure to diethylstilbestrol [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1733.

Genome-Wide Association Studies of Endometrial Cancer: Latest Developments and Future Directions.

Endometrial cancer, the most commonly diagnosed cancer of the female reproductive tract in developed countries, has a heritable component. To date, 16 genetic risk regions have been robustly discovered by genome-wide association studies (GWAS) of endometrial cancer. Post-GWAS analyses including expression quantitative trait loci analysis and laboratory-based functional studies have been successful in identifying genes and pathways involved in endometrial carcinogenesis. Mendelian randomization analysis studies have confirmed factors causal for endometrial cancer risk, including increased body mass index and early onset of menarche. In this review, we summarize findings from GWAS and post-GWAS analyses of endometrial cancer. We discuss clinical implications of these findings, current knowledge gaps, and future directions for the study of endometrial cancer genetics.

Abstract 604: Biomarkers of amino acid metabolism and endometrial cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO)

Abstract Background: Incidence and mortality rates for endometrial cancer have steadily increased during the past decade. Beyond the well-known risk factors of obesity and unopposed estrogen menopausal hormone therapy (MHT), our understanding of the molecular etiology of this disease is limited and few biomarkers for risk are identified. To address this data gap, we explored circulating markers of amino acid metabolism and endometrial cancer risk—with specific interest in assessing whether the associations with branch chain amino acids (BCAAs) differed by known endometrial cancer risk factors. Methods: We used data from a nested case-control study within the screening arm of the PLCO trial (353 endometrial cancer cases, 353 controls, age 55-74 years at enrollment). We measured absolute concentrations of amino acid metabolism markers in pre-diagnostic serum using targeted mass spectrometry assays. Conditional and unconditional logistic regression adjusted for potential confounders (and matching factors in the latter) was used to estimate associations between these circulating markers and endometrial cancer overall, by body mass index (BMI), and by MHT use at baseline. We evaluated heterogeneity across these groups via likelihood ratio tests (p for interaction [p-int]). Results: In the full population, associations with endometrial cancer were generally masked/not identified, but we noted substantial effect modification by MHT use and BMI. A doubling in endometrial cancer risk was suggested with the highest concentrations of BCAAs, but only among women not using MHT (odds ratio and 95% confidence interval for the highest quintile [Q5] versus lowest [Q1]: leucine 1.87, 0.91–3.83; isoleucine 2.44, 1.17–5.09; and valine 1.86, 0.89–3.87; p-int &amp;lt;0.15 for all). We similarly noted that high levels of leucine (Q5 v. Q1: 3.26, 0.96–11.08, p-int 0.39) and valine (Q5 v. Q1: 6.40, 1.49–27.47, p-int 0.08) were associated with risk among obese women, but not those with normal BMIs. The highest levels of 3-hydroxyisobutyrate, a bioactive valine precursor, doubled risk among non-MHT users (CI 1.09–4.51, p-int &amp;lt;0.05) and quadrupled it among obese women (CI 1.45–14.86, p-int 0.33). High proline levels were associated with 4- to 7-fold increases in risk among non-MHT users (CI 1.68–10.01) and obese women (CI 2.11–26.81), respectively (p-int&amp;lt;0.05 for both). Conclusions: Our findings suggest that the regulation of BCAA metabolism may be involved in endometrial carcinogenesis, but this influence depends on other risk factors for the disease. Use of MHT overshadowed potential risks with most markers evaluated, and we identified increased risks associated with a variety of markers only among obese women. Amino acids play crucial roles in cellular energy metabolism and our results highlight the importance of finding ways to maintain and improve metabolic health in postmenopausal women. Citation Format: Kara A. Michels, Stephanie J. Weinstein, Nicolas Wentzensen, Ruth M. Pfeiffer, Britton Trabert. Biomarkers of amino acid metabolism and endometrial cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 604.

MiRNAs as Candidate Biomarker for the Accurate Detection of Atypical Endometrial Hyperplasia/Endometrial Intraepithelial Neoplasia.

Endometrial cancer is the most common gynecologic malignancy in developed countries. Estrogen-dependent tumors (type I, endometrioid) account for 80% of cases and non-estrogen-dependent (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 binding to 3′-untranslated region of target mRNAs. In the current study, we identified a microRNAs 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 to be highly useful for the clinical management of patients because hyperplasia with an atypical change is associated with a higher risk of developing cancer. We show that the combination of miR-205, −146a, and −1260b has the best predictive power in discriminating these two conditions (>90%). With the aim to find a biological role for these three microRNAs, we focused our attention on a common putative target involved in endometrial carcinogenesis: the oncosuppressor gene SMAD4. We showed that miRs-146a,−205, and−1260b directly target SMAD4 and their enforced expression induced proliferation and migration of Endometrioid Cancer derived cell lines, Hec1a cells. These data suggest that microRNAs-mediated impairment of the TGF-β pathway, due to inhibition of its effector molecule SMAD4, is a relevant molecular alteration in endometrial carcinoma development. Our findings show a potential diagnostic role of this microRNAs signature for the accurate diagnosis of Endometrial hyperplasia with atypia/Endometrial Intraepithelial Neoplasia and improve the understanding of their pivotal role in SMAD4 regulation.

Impact of body mass index and fat distribution on sex steroid levels in endometrial carcinoma: a retrospective study

BackgroundObesity is an important cause of multiple cancer types, amongst which endometrial cancer (EC). The relation between obesity and cancer is complicated and involves alterations in insulin metabolism, response to inflammation and alterations in estradiol metabolism. Visceral obesity is assumed to play the most important role in the first two mechanisms, but its role in estradiol metabolism is unclear. Therefore, this retrospective study explores the relationship of body mass index (BMI), visceral fat volume (VAV) and subcutaneous fat volume (SAV) and serum levels of sex steroids and lipids in patients with endometrial cancer.MethodsThirty-nine postmenopausal EC patients with available BMI, blood serum and Computed Tomography (CT) scans were included. Serum was analyzed for estradiol, dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, cholesterol, triglycerides and high (HDL), low (LDL) and non-high density (NHDL) lipoprotein. VAV and SAV were quantified on abdominal CT scan images. Findings were interpreted using pearson correlation coefficient and linear regression with commonality analysis.ResultsSerum estradiol is moderately correlated with BMI (r = 0.62) and VAV (r = 0.58) and strongly correlated with SAV (r = 0.74) (p < 0.001 for all). SAV contributes more to estradiol levels than VAV (10.3% for SAV, 1.4% for VAV, 35.9% for SAV and VAV, p = 0.01). Other sex steroids and lipids have weak and moderate correlations with VAV or SAV.ConclusionsThis study shows that serum estradiol is correlated with BMI and other fat-distribution measures in postmenopausal endometrial cancer patients. Subcutaneous fat tissue contributes more to the estradiol levels indicating that subcutaneous fat might be relevant in endometrial cancer carcinogenesis.

Postmenopausal Androgen Metabolism and Endometrial Cancer Risk in the Women’s Health Initiative Observational Study

After menopause, several androgens continue to be produced primarily by the adrenal glands; these can be converted into estrogens via aromatization or into androgen metabolites. It is unclear if androgens are associated with endometrial cancer risk independently of their being precursors to estrogens or if alternative metabolic pathways influence risk. We measured prediagnostic serum concentrations of 12 androgens and their metabolites using highly sensitive liquid chromatography-tandem mass spectrometry assays in a nested case-control study of postmenopausal women from the Women's Health Initiative Observational Study (313 endometrial cancer case subjects, 354 matched control subjects). Estrogens were previously assayed. We used conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for endometrial cancer with adjustment for confounders. Compared to the lowest concentrations, the highest levels of adrenal androgens were associated with increased endometrial cancer risk: dehydroepiandrosterone (5th vs 1st quintile: OR = 1.85, 95% CI = 1.06 to 3.25), androstenedione (OR = 2.36, 95% CI = 1.34 to 4.16), and testosterone (OR = 1.91, 95% CI = 1.12 to 3.24). Downstream androgen metabolites were not associated with endometrial cancer. Although increased risks for the parent androgens were still suggested after adjustment for unconjugated estradiol, the associations attenuated, and with the exception of androstenedione, were no longer statistically significant. We also evaluated ratios of estrogens relative to their androgenic precursors; both higher unconjugated estrone:androstenedione and higher unconjugated estradiol:testosterone were associated with increased endometrial cancer risk. We identified increased risks for endometrial cancer with the highest levels of adrenal androgens and high levels of estrogens relative to these androgens. As adrenal androgens can be aromatized to estrogens, this suggests androgens likely influence endometrial carcinogenesis via estrogen metabolism.

Epithelial to Mesenchymal Transition and Cell Biology of Molecular Regulation in Endometrial Carcinogenesis.

Endometrial carcinogenesis is involved in several signaling pathways and it comprises multiple steps. The four major signaling pathways—PI3K/AKT, Ras/Raf/MEK/ERK, WNT/β-catenin, and vascular endothelial growth factor (VEGF)—are involved in tumor cell metabolism, growth, proliferation, survival, and angiogenesis. The genetic mutation and germline mitochondrial DNA mutations also impair cell proliferation, anti-apoptosis signaling, and epithelial–mesenchymal transition by several transcription factors, leading to endometrial carcinogenesis and distant metastasis. The PI3K/AKT pathway activates the ransforming growth factor beta (TGF-β)-mediated endothelial-to-mesenchymal transition (EMT) and it interacts with downstream signals to upregulate EMT-associated factors. Estrogen and progesterone signaling in EMT also play key roles in the prognosis of endometrial carcinogenesis. In this review article, we summarize the current clinical and basic research efforts regarding the detailed molecular regulation in endometrial carcinogenesis, especially in EMT, to provide novel targets for further anti-carcinogenesis treatment.

Genome-wide DNA methylation profile of early-onset endometrial cancer: its correlation with genetic aberrations and comparison with late-onset endometrial cancer.

The present study was performed to clarify the significance of DNA methylation alterations during endometrial carcinogenesis. Genome-wide DNA methylation analysis and targeted sequencing of tumor-related genes were performed using the Infinium MethylationEPIC BeadChip and the Ion AmpliSeq Cancer Hotspot Panel v2, respectively, for 31 samples of normal control endometrial tissue from patients without endometrial cancer and 81 samples of endometrial cancer tissue. Principal component analysis revealed that tumor samples had a DNA methylation profile distinct from that of control samples. Gene Ontology enrichment analysis revealed significant differences of DNA methylation at 1034 CpG sites between early-onset endometrioid endometrial cancer (EE) tissue (patients aged ≤40 years) and late-onset endometrioid endometrial cancer (LE) tissue, which were accumulated among ‘transcriptional factors’. Mutations of the CTNNB1 gene or DNA methylation alterations of genes participating in Wnt signaling were frequent in EEs, whereas genetic and epigenetic alterations of fibroblast growth factor signaling genes were observed in LEs. Unsupervised hierarchical clustering grouped EE samples in Cluster EA (n = 22) and samples in Cluster EB (n = 12). Clinicopathologically less aggressive tumors tended to be accumulated in Cluster EB, and DNA methylation levels of 18 genes including HOXA9, HOXD10 and SOX11 were associated with differences in such aggressiveness between the two clusters. We identified 11 marker CpG sites that discriminated EB samples from EA samples with 100% sensitivity and specificity. These data indicate that genetically and epigenetically different pathways may participate in the development of EEs and LEs, and that DNA methylation profiling may help predict tumors that are less aggressive and amenable to fertility preservation treatment.