Subtype Of Endometrial Cancer Research Articles

Association of APOBEC3A/B deletion variant with endometrial cancer risk in Norwegian population: A case-control study (242)

<b>Objectives:</b> APOBEC3 family of proteins play important roles in intrinsic responses to viral infection by introducing mutations into the viral nucleic acids. APOBEC3 activity targeting the host cell's DNA may lead to mutations contributing to tumorigenesis. Uterine cancers are found to be linked with three APOBEC associated signatures; single-base substitution signatures 2 and -13 and double-base substitution signature 11. A germline deletion of 30Kb in chromosome 22 affecting the APOBEC3A and -B genes leads to the formation of a hybrid transcript, APOBEC3A/B, found to be more stable than the wild-type APOBEC3A and causes more DNA damage through higher protein levels. To the best of our knowledge, the potential association between the APOBEC3A/B deletion variant and the risk of endometrial cancer has not yet been assessed. This study aimed to evaluate the APOBEC3A/B deletion as a potential risk modulating factor for endometrial cancer. <b>Methods:</b> DNA extracted from blood samples of Norwegian (Caucasian) women diagnosed with primary uterine adenocarcinoma (<i>n</i>=1,470), and healthy controls (<i>n</i>=1,918) were screened for germline APOBEC3A/B deletion variant using quantitative polymerase chain reaction high-resolution melting (qPCR-HMR) curves. For technical validation, 35.4% of cases were genotyped for SNP rs12628403 (Chr 22:38962032), an SNP in proximity to the APOBEC3A/B-deletion start point that is found in strong linkage disequilibrium with the deletion allele. The potential difference in results from APOBEC3A/B deletion and rs12628403-analyses were considered negligible due to a very low recombination rate of 5.8x10-3. <b>Results:</b> Cases and controls were in Hardy-Weinberg equilibrium for genotype distribution (p=0.78 and p>0.4, with a MAF of 0.072 and 0.094, respectively). Our study cohort showed a reduced risk of endometrial cancer in dominant and allele models (OR: 0.75, 95 % CI: 0.62-0.91, p=0.003 and OR: 0.75, 95 % CI: 0.63-0.90, p=0.0002, respectively). In a subgroup analysis by histology, endometrioid endometrial cancer showed similar patterns (dominant model: OR: 0.64, 95% CI: 0.51-0.79, p=0.1x10-3 and allele model: OR: 0.64, 95% CI: 0.52-0.79, p=0.1x10-3). No clear risk association was observed in non-endometrioid endometrial cancer subtype. Among age subgroups generated with a 10-year cut-off, dominant and allele models yielded a significantly reduced cancer risk in individuals in the age range 50-59 (OR: 0.51, 95% CI: 0.33-0.78, p=0.002 and OR: 0.54, 95% CI: 0.35-0.81, p=0.002, respectively) and 60-69 (OR = 0.62, 95% CI=0.43-0.88, p=0.8x10-3 and OR=0.62, CI=0.44-0.88, p=0.005, respectively). <b>Conclusions:</b> APOBEC3A/B deletion variant is associated with reduced endometrial cancer risk in Norwegian women.

Evaluation of racial disparities in time to presentation, diagnosis, and gynecologic oncology referral in women with serous endometrial cancer (431)

<b>Objectives:</b> The frequency and mortality of endometrial cancer (EC) continue to increase in the United States; this is most striking for aggressive EC subtypes, such as serous tumors. Black women have higher rates of serous EC and lower survival rates compared to White women. We aimed to delineate racial differences in diagnosis and referral between Black and White women with serous EC treated at a quaternary academic medical center as contributing factors to this disparity. <b>Methods:</b> We extracted the following from the electronic medical record of women with confirmed serous EC seen at our center from 2001-2019: demographics, presenting symptoms including duration, details of evaluation and diagnosis, dates of initial visit with gynecologic oncology, and stage of cancer at presentation. We categorized the time from symptom onset to initial evaluation, from presentation to diagnosis, and from diagnosis to visit with gynecologic oncology. Chi-square tests were used to compare these times across racial categories. <b>Results:</b> Data from the medical records of 248 women were analyzed (106 Black women and 142 White women). The median age was 68 years. Presenting symptoms were similar between Black and White women, with abnormal bleeding being the most common (82.8% of Black women, 82.3% of White women, p=0.84). A trend toward presentation at a higher stage was identified for Black women (41.2% Black women with stage III and IV disease, 33.1% White women with stage III and IV disease; p=0.26). Black women had a longer duration of symptoms prior to presentation: 36.4% of Black women presented after >3 months (mos) of symptoms, while 18% of White women presented after >3mo of symptoms (p=0.01). Black women trended toward longer times to diagnosis after the presentation: 45.9% of Black women were diagnosed >3mos after the presentation compared to 33.3% of White women (p=0.14). The mode of diagnosis was similar between Black and White women, with endometrial biopsy being the most common (66% of Black women, 54% of White women, p=0.06). There was no significant difference among these groups in time to see a gynecologic oncologist after a diagnosis was made: 94% of Black women were seen within one mo as compared to 92% of White women (p=0.38). <b>Conclusions:</b> We identified racial disparities in the presentation and diagnosis of serous EC, including a longer duration of symptoms prior to presentation for Black compared to White women. Statistical significance was not reached with regard to the difference in time to diagnosis after the presentation, but a trend was identified in this duration being longer for Black versus White women. No differences were noted in time to referral to gynecologic oncology after diagnosis between Black and White women. Future work should focus on outreach strategies to ensure timely workup for the signs and symptoms of EC among Black women.

Landscape of Genomic Alterations and Biomarkers in Endometrial Cancer (EC) Identified by Comprehensive Genomic Profiling (CGP) of Peripheral Blood Biopsies (181)

<b>Objectives:</b> Circulating tumor DNA (ctDNA) extracted from peripheral blood presents an alternative to tumor tissue for molecular testing when the latter is unavailable. We explored the landscape of genomic alterations (GA) from liquid biopsies of patients with advanced/recurrent EC to determine utility to inform prognosis, treatment selection, and clinical trial eligibility. <b>Methods:</b> Comprehensive genomic profiling (CGP) by hybrid capture sequencing on peripheral blood-derived cell-free DNA (cfDNA) from 193 patients with EC (b-EC cohort) interrogated 324 genes (including 75 with enhanced sensitivity and 21 with introns; F1LCDx) and assessed microsatellite instability-high status (MSI-H; detected/not detected) and blood tumor mutational burden (bTMB; muts/Mb). The proportion of cfDNA predicted to be tumor-derived (ctDNA) was calculated as tumor fraction (TF). Additionally, 7148 tissue samples from patients with advanced EC (t-EC cohort) were analyzed by a 324-gene CGP assay (F1CDx) for comparison to the b-EC cohort. <b>Results:</b> Sixty-seven of 193 b-EC were submitted with specified histologic diagnosis (25 endometrioid [13%], 21 serous [11%], 12 carcinosarcomas [6%], seven clear cells, and two of mixed histology), while the remaining 126 b-EC (65%) were not further specified. Patients had a median age of 69 years (range: 36 -87 years), 182 (94%) had detectable ctDNA, and 18% had a TF >10%. Among b-EC with detectable ctDNA, the median bTMB was 2.5mut/Mb. Eleven b-EC had MSI-H status detected, and among them, the median bTMB was 29 mut/Mb (range: 14 - 109). At least one GA in a potentially targetable pathway was identified in 48% of b-EC, including PI3K/mTOR, MEK, HRR, and receptor tyrosine kinases (Table 1). In cases with TF>10%, alteration frequencies for these genes were generally higher and more similar to rates detected in t-EC. Six b-EC with <i>ERBB2</i> alterations (three amplifications and three activating short variants) and two b-EC with an activating <i>ESR1</i> mutation (Y537S; commonly seen in endocrine-resistant breast cancer) were detected. Sixteen patients had <i>BRCA1/2</i> alterations, of which six had variant allele frequencies suggesting possible germline origin. Other potentially targetable alterations were detected in <i>EGFR</i> (six short variants) and <i>ALK</i> rearrangements (two cases). The most frequently altered gene was <i>TP53</i>, seen in 58% b-EC and 74% of TF>10 b-EC (vs 63% t-EC; p=0.28). Since clonal hematopoiesis (CH) can contribute to alterations in cfDNA, significantly more b-EC samples had one or more alterations in potential CH genes (<i>DNMT3a</i>, <i>TET2, ASXL1</i>) compared to t-EC (53% vs 11%; p<0.0001). <b>Conclusions:</b> A total of 94% of patients with b-EC had detectable ctDNA, and 48% had a potentially targetable alteration or biomarker, confirming liquid biopsy as a viable alternative in EC when appropriate tumor tissue is lacking and could increase access to clinical trials. MSI-H status, high-bTMB, and alterations detected in ctDNA could also suggest an EC subtype with associated prognostic implications and/or molecular mechanism of treatment resistance. Since sensitivity depends on ctDNA shed, negative liquid biopsy results must be confirmed with tumor tissue testing if clinically appropriate.

The Geographic Context of Racial Disparities in Aggressive Endometrial Cancer Subtypes: Integrating Social and Environmental Aspects to Discern Biological Outcomes.

The number of Endometrial Carcinoma (EC) diagnoses is projected to increase substantially in coming decades. Although most ECs have a favorable prognosis, the aggressive, non-endometrioid subtypes are disproportionately concentrated in Black women and spread rapidly, making treatment difficult and resulting in poor outcomes. Therefore, this study offers an exploratory spatial epidemiological investigation of EC patients within a U.S.-based health system’s institutional cancer registry (n = 1748) to search for and study geographic patterns. Clinical, demographic, and geographic characteristics were compared by histotype using chi-square tests for categorical and t-tests for continuous variables. Multivariable logistic regression evaluated the impact of risks on these histotypes. Cox proportional hazard models measured risks in overall and cancer-specific death. Cluster detection indicated that patients with the EC non-endometrioid histotypes exhibit geographic clustering in their home address, such that congregate buildings can be identified for targeted outreach. Furthermore, living in a high social vulnerability area was independently associated with non-endometrioid histotypes, as continuous and categorical variables. This study provides a methodological framework for early, geographically targeted intervention; social vulnerability associations require further investigation. We have begun to fill the knowledge gap of geography in gynecologic cancers, and geographic clustering of aggressive tumors may enable targeted intervention to improve prognoses.

Abstract 647: Association between adrenal-restrictive HSD3B1 inheritance and hormone independent subtypes of endometrial and breast cancer

Abstract Breast and endometrial cancer are both malignancies that can be classified into subtypes based on their hormone dependence, such as estrogen receptor (ER)-positive vs. ER-negative breast cancer and low-grade vs. high-grade endometrial cancer. The gene HSD3B1 encodes the steroid metabolism enzyme 3β-hydroxysteroid dehydrogenase 1, which catalyzes a critical step in conversion of adrenal precursor steroids to potent androgens and estrogens. Associations between the missense-encoding germline variant rs1047303 in HSD3B1 have been described to affect outcomes of castration-resistant prostate cancer and associated with ER positivity in postmenopausal breast cancer. The adrenal-permissive 1245C allele enables greater production of androgens and estrogens from adrenal precursors, whereas the adrenal-restrictive 1245A allele limits this reaction pathway. Using data from The Cancer Genome Atlas’s TCGA-UCEC and TCGA-BRCA projects, we interrogated whether the adrenal-restrictive rs1047303 genotype was associated with less hormone-driven genomic clusters of endometrial and breast cancer. We determined the genotype frequencies for different tumor subtypes, as classified by the genomic analysis of Sanchez-Vega, et al. (2018). The adrenal-restrictive HSD3B1(1245A) allele was associated with the copy number (CN) high cluster of endometrial cancer (OR 1.59, 95% CI 1.12-2.26, p = 0.0098), notably composed of serous and high-grade endometrioid endometrial cancers which are less estrogen-dependent than low-grade endometrioid tumors. Similarly, the adrenal-restrictive HSD3B1(1245A) was associated with the basal subtype of breast cancer (OR 1.54 [1.13-2.09], p = 0.0057), a subtype that is largely ER-negative and is known to share genomic features with serous-type endometrial cancers. Lastly, we interrogated overall survival of endometrial cancer patients in the UK Biobank and found that patients homozygous for the adrenal-restrictive HSD3B1(1245A) had worse overall survival (HR 1.39 [1.16-1.68], p = 0.00049) and cancer-specific survival (HR 1.39 [1.14-1.70], p = 0.0013), a finding consistent with the A allele being enriched in the more aggressive CN-high subtype of endometrial cancer. Taken together, these findings suggest a role for adrenal-restrictive vs. adrenal-permissive steroidogenesis, by way of rs1047303 genotype, in the development of and/or outcomes from at least three different commonly hormone-associated types of cancer: prostate, breast, and endometrial. Citation Format: Jeffrey M. McManus, Roberto Vargas, Peter Bazeley, Navin Sabharwal, Nima Sharifi. Association between adrenal-restrictive HSD3B1 inheritance and hormone independent subtypes of endometrial and breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 647.

Abstract LB081: GAS6-AXL inhibition by AVB-500 overcomes resistance to paclitaxel in endometrial cancer by decreasing tumor cell glycolysis

Abstract Objective/Background: Chemotherapy is often ineffective in advanced stage and aggressive histologic subtypes of endometrial cancer. Overexpression of the receptor tyrosine kinase AXL has been found to be associated with therapeutic resistance, metastasis, and poor prognosis in endometrial cancer. Our objective was to identify whether inhibition of AXL through a novel, selective targeted agent, AVB-500, would improve sensitivity to paclitaxel. Additionally, we sought to determine whether the mechanism for this improved sensitivity was through metabolic regulation. Methods: Immunohistochemistry (IHC) was performed on a tissue microarray containing specimens from patients with primary and metastatic uterine serous carcinoma. Blind scoring was performed by two reviewers. Kaplan-Meier methods were used to generate time-to-event curves. Cell viability was performed with high-grade endometrial, chemo-resistant cell lines, ARK1 and PUC198. Cells were treated with paclitaxel and with AVB-500+paclitaxel. Intraperitoneal (IP) ARK1 or PUC198 tumors were treated with vehicle, AVB-500, paclitaxel, or AVB-500+paclitaxel. A Seahorse Analyzer was used for glycolytic rate assays. Isotope tracing was used for in vivo metabolite abundance quantification. Results: We found that both GAS6 and AXL expression were higher by IHC in tumors with a poor response to chemotherapy compared to tumors with a good response to chemotherapy (GAS6: 40.9% vs. 30.4%, P=0.012; AXL: 60.7% vs. 42.7%, P=0.013). Median PFS and OS were longer in patients with low GAS6 expressing tumors compared to high GAS6 expressing tumors (PFS: 33.6 mo vs. 10.6 mo, P=0.003; OS: 39.5 mo vs. 27.7 mo, P=0.003). We showed that chemotherapy resistant endometrial cancer cell lines, ARK1 and PUC198 had improved sensitivity and synergy with paclitaxel when treated in combination with AVB-500. ARK1 and PUC198 in vivo IP models had significantly fewer tumors (ARK1: P=0.007; PUC198: P=0.029) and decreased tumor weight (ARK1: P&amp;lt;0.001; PUC198: P=0.006) when treated with AVB-500+paclitaxel vs. paclitaxel alone. Treatment with AVB-500 + paclitaxel decreased AKT signaling which resulted in a decrease in basal glycolysis. Finally, treatment with AVB-500 + paclitaxel decreased multiple glycolytic metabolites, including fructose-1,6-bisphosphate (P=0.002), 3-phosphoglyceric acid (P=0.014), phosphoenolpyruvate (P=0.013), and lactate (P=0.024) vs. treatment with paclitaxel alone. Conclusions: Our study provides strong pre-clinical rationale for combining AVB-500 with paclitaxel in aggressive endometrial cancer models. Additionally, continued identification of viable biomarkers is critical to the success of targeted therapies such as AVB-500. Given AXL’s role in glucose homeostasis, one or more glycolytic intermediates may prove to be a useful biomarker to help predict sensitivity in patients, thus tailoring who would benefit from this treatment combination. Citation Format: Shaina F. Bruce, Kevin Cho, Hollie Noia, Elena Lomonosova, Elizabeth Stock, Alyssa Oplt, Barbara Blachut, Mary M. Mullen, Lindsay M. Kuroki, Andrea R. Hagemann, Carolyn K. McCourt, Premal H. Thaker, Dineo Khabele, Matthew A. Powell, David G. Mutch, Leah P. Shriver, Gary J. Patti, Katherine C. Fuh. GAS6-AXL inhibition by AVB-500 overcomes resistance to paclitaxel in endometrial cancer by decreasing tumor cell glycolysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB081.

Abstract 3341: Synthetic lethality by targeting ribonucleotide reductase in PP2A deficient uterine serous carcinoma

Abstract Uterine serous carcinoma (USC) is a highly aggressive endometrial cancer subtype with limited therapeutic options and a lack of targeted therapies. While mutations to PPP2R1A, encoding the predominant protein phosphatase 2A (PP2A) scaffolding protein Aα, occur in 30-40% of cases, the clinical actionability of these mutations has not been studied. Here, we show that mutation to Aα results in synthetic lethality to treatment with inhibitors of ribonucleotide reductase (RNR), and multiple models of Aα mutant uterine serous tumors were sensitive to Clofarabine, an RNR inhibitor in vivo. Aα mutant cells displayed impaired checkpoint signaling upon RNRi treatment, and subsequently accumulated more DNA damage than wild type cells. This was PP2A dependent as complete inhibition of PP2A activity using LB-100, a catalytic site inhibitor, sensitized wild type USC cells to RNRi. Analysis of TCGA data indicated that inactivation of PP2A, through loss of PP2A subunit expression, was prevalent in USC, with 88% of USC patients harboring loss of at least one PP2A gene. In contrast, loss of PP2A subunit expression was rare in uterine endometrioid carcinomas. While RNR inhibitors are not routinely used for uterine cancers, we identified a cohort of patients with recurrent disease treated with gemcitabine at MSKCC as a second or later line therapy. In a retrospective analysis of this cohort there was a trend for improved outcomes in USC patients treated with RNRi gemcitabine compared to patients with endometrioid histology. Overall, our data provide experimental evidence to support the use of ribonucleotide reductase inhibitors for the treatment of USC. Citation Format: Caitlin M. O'Connor, Sarah E. Taylor, Kathryn M. Miller, Lauren Hurst, Terrance J. Haanen, Tahra K. Suhan, Kaitlin P. Zawacki, Fallon K. Noto, Jonida Trako, Arathi Mohan, Jaya Sangodkar, Dmitriy Zamarin, Analisa DiFeo, Goutham Narla. Synthetic lethality by targeting ribonucleotide reductase in PP2A deficient uterine serous carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3341.

Genomic Validation of Endometrial Cancer Patient-Derived Xenograft Models as a Preclinical Tool.

Endometrial cancer (EC) is the second most frequent gynecological cancer worldwide. Although improvements in EC classification have enabled an accurate establishment of disease prognosis, women with a high-risk or recurrent EC face a dramatic situation due to limited further treatment options. Therefore, new strategies that closely mimic the disease are required to maximize drug development success. Patient-derived xenografts (PDXs) are widely recognized as a physiologically relevant preclinical model. Hence, we propose to molecularly and histologically validate EC PDX models. To reveal the molecular landscape of PDXs generated from 13 EC patients, we performed histological characterization and whole-exome sequencing analysis of tumor samples. We assessed the similarity between PDXs and their corresponding patient’s tumor and, additionally, to an extended cohort of EC patients obtained from The Cancer Genome Atlas (TCGA). Finally, we performed functional enrichment analysis to reveal differences in molecular pathway activation in PDX models. We demonstrated that the PDX models had a well-defined and differentiated molecular profile that matched the genomic profile described by the TCGA for each EC subtype. Thus, we validated EC PDX’s potential to reliably recapitulate the majority of histologic and molecular EC features. This work highlights the importance of a thorough characterization of preclinical models for the improvement of the success rate of drug-screening assays for personalized medicine.

Identification of a novel subtype of endometrial cancer with unfavorable outcome using artificial intelligence-based histopathology image analysis.

5594 Background: Molecular subtyping of endometrial cancer (EC), unlike histopathological evaluation, offers an objective and reproducible classification system that has strong prognostic value and therapeutic implications. The Proactive Molecular risk classifier for Endometrial cancer (ProMisE) was developed by our team as a pragmatic, cost-effective, and clinically applicable molecular classifier for EC patients. ProMisE has four subtypes: (i) POLE mutant ( POLEmut), (ii) mismatch repair deficient (MMRd), (iii) p53 abnormal (p53abn) by immunohistochemistry, and (iv) NSMP (No Specific Molecular Profile), lacking any of the defining features of the other three subtypes. While ProMisE subtypes are associated with clinical outcomes, within each subtype, there are clinical/prognostic outliers. This is particularly true within the largest ProMisE subtype; NSMP (representing ̃50% of ECs), where a subset of patients experience a very aggressive disease course, comparable to what is observed in patients with p53abn ECs. Methods: We hypothesized that objective assessment of the digitized hematoxylin and eosin (H&amp;E)-stained histopathology slides of the largest and most diverse EC subset, NSMP, could potentially identify clinical outcome outliers. As such, we developed an artificial intelligence (AI)-based image analysis model to identify the NSMP cases that had similar histopathological features to the p53abn subtype, as assessed by H&amp;E stain. We used a discovery cohort of 182 and an external validation cohort of 195 NSMP ECs. Results: Our AI-based image analysis model, based on deep convolutional neural networks, identified 21 (11.5%) out of the 182 NSMP cases with similar histopathological features as p53abn cases. We refer to these cases as ‘p53abn-like’ NSMPs. Compared to the rest of the NSMP cases, these cases had markedly inferior disease-specific survival (DSS) (10-year DSS 58.9% vs. 93.1% ( p&lt;3.44e-8)) and progression-free survival (PFS) (10-year PFS 55.1% vs. 91.4% ( p&lt;3.76e-6)). These findings were confirmed in our validation cohort, with 10.7% of the 195 patients categorized as ‘p53abn-like’ tumors with 10-year DSS of 82% vs. 51.3% ( p&lt;5.28e-5) and PFS of 89.3% vs. 56.6% (p&lt;2.15e-4). Conclusions: Utilizing an AI-based approach for histopathology image analysis, we have discovered ‘p53abn-like’ NSMPs, a novel subtype of NSMP ECs with morphological features similar to p53abn cases. ‘p53abn-like’ NSMPs exhibit similar clinical behavior as p53abn, having noticeably inferior outcome compared to the rest of the NSMP cases in two independent cohorts. These findings warrant further molecular investigation of this novel subtype of EC to identify the biological underpinning and future therapeutic strategies.

Molecular classification of endometrial cancer of Chinese population.

e17623 Background: Endometrial cancer (EC) is one of the most prevalent gynecologic tumors. Current diagnosis and treatment of EC no longer rely solely on traditional histopathological classification. Nevertheless, molecular classification of EC demonstrated clear prognostic value and may guide clinical decision. Methods: In this study, archived tissue specimens from 240 EC patients from Department of Pathology, Peking University People’s Hospital. Four subtypes [POLE ultramutated (POLE mut), microsatellite instability high (MSI-H), copy number low (CNL), and copy number high (CNH)] were stratified by next-generation sequencing (NGS) panel (Amoy Diagnostics, Xiamen, China) targeting POLE, TP53, BRCA1, and BRCA2 genes and microsatellite instability (MSI) status. Immunohistochemistry (IHC) was applied to detect the expression of P53, MMR and other related proteins. Results: Distribution of the EC subtypes in 240 patients was 13 (5.42%) of POLE mut, 36 (15.00%) of MSI-H, 41 (17.08%) of CNH, and 150 (62.50%) of CNL. Compared to published results of EC subtypes in Caucasian including TCGA, ProMisE as well as TransPORTEC, real-world data on Chinese ECs displayed a significantly larger proportion of CNL. In addition, novel biomarkers such as DUSP1, MCF7 and BUB1, which were independent prognostic marker from our previous research were validated. Also, it was found that BRCA2 appeared to be more prevalent in EC than BRCA1. Further analysis revealed that the overall consistency for NGS-based and IHC-based TP53 abnormalities detection and MSI/MMR status assessment were as high as 87.5% and 100%, respectively. Conclusions: Chinese ECs have unique molecular characteristics. In order to perform accurate molecular typing of Chinese ECs, more molecular indicators that match the characteristics of the Chinese population need to be added to the existing classifiers. NGS-based panel is easy to operate and replicate with high accuracy. Thus, it is a viable alternative to IHC in EC molecular classification.

The Prognostic Effect of HER2 Gene Amplification in High-Grade Endometrial Carcinomas and its Correlation with Protein Overexpression.

Introduction. New therapeutic agents and biomarkers are needed for the treatment of aggressive endometrial cancer subtypes. Recently, HER2 has been recommended to be tested routinely in serous endometrial cancers. The aim of this study is to investigate the correlation between HER2 (ERBB2) protein overexpression and HER2 gene amplification and the relationship of HER2 gene amplification with prognosis in cancers with serous morphology. In addition, the concordance of HER2 testing in paired curettage and hysterectomy specimens is also investigated. Methods. Twenty five serous carcinomas and 8 carcinosarcomas with a serous morphology were included in the study. HER2 staining was performed on whole tissue sections by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH). The system, which was proposed by Fader et al was used to evaluate the stainings. Results. Protein overexpression was detected in 27.3% (n = 9) of the cases, and gene amplification in 30.3% (n = 10). A significant positive correlation was found between the two methods (P < .0001). HER2 IHC revealed a heterogeneous staining pattern, such as intense complete membranous in solid areas, and basolateral in papillary and glandular areas. HER2 gene amplification was significantly associated with shorter overall (P = .005) and disease-free (P = .014) survival. The concordence of the results in curettage and hysterectomy specimens was also significantly high. Conclusion. HER2 is an important prognostic and predictive marker for endometrial cancers with serous morphology. HER2 IHC/ISH testing can be performed by using diagnostic curettage specimens which contain enough viable tumor cells. However, pathologists should be aware of the intratumoral heterogeneity for HER2 staining.

PRAME Expression in Endometrioid and Serous Endometrial Carcinoma: A Potential Immunotherapeutic Target and Possible Diagnostic Pitfall.

Preferentially expressed antigen in melanoma (PRAME) is a cancer testes antigen initially employed as a diagnostic marker for melanoma. Although negative in most normal tissues, its expression has been reported in benign endometrial glands. Additionally, PRAME expression has been identified in a growing list of solid and hematologic malignancies and is of interest as a predictive biomarker, as cancer vaccination strategies and adoptive T-cell transfer targeting this molecule are under clinical investigation; additionally, PRAME may identify candidates for retinoid therapy. However, expression of PRAME has not been well-studied in endometrial cancers. We herein evaluate PRAME expression in endometrial carcinomas to better characterize its limitations as a diagnostic melanoma marker as well as its potential as a predictive biomarker in endometrial carcinomas. PRAME expression was evaluated in 256 endometrioid (n=235) and serous (n=21) endometrial carcinomas via tissue microarray. In all, 89% (227/256) demonstrated some degree of nuclear PRAME expression, including 88% (207/235) of endometrioid carcinomas and 95% (20/21) of serous carcinomas. Diffuse (>50%) expression was observed in 70% (179/256) of all cases, including 69% (163/235) of endometrioid carcinomas and 76% (16/21) of serous carcinomas. There was no association between degree of expression and grade, mismatch repair protein status, or stage. The widespread expression of PRAME in endometrial carcinomas suggests this marker should not be interpreted as specific for melanoma in this context. However PRAME may have utility as a predictive biomarker in endometrial cancer, and expansion of testing of PRAME-based therapies to endometrioid and serous endometrial carcinomas may lead to new therapeutic options for these endometrial cancer subtypes.

GAS6-AXL Inhibition by AVB-500 Overcomes Resistance to Paclitaxel in Endometrial Cancer by Decreasing Tumor Cell Glycolysis.

Chemotherapy is often ineffective in advanced-stage and aggressive histologic subtypes of endometrial cancer. Overexpression of the receptor tyrosine kinase AXL has been found to be associated with therapeutic resistance, metastasis, and poor prognosis. However, the mechanism of how inhibition of AXL improves response to chemotherapy is still largely unknown. Thus, we aimed to determine whether treatment with AVB-500, a selective inhibitor of GAS6-AXL, improves endometrial cancer cell sensitivity to chemotherapy particularly through metabolic changes. We found that both GAS6 and AXL expression were higher by immunohistochemistry in patient tumors with a poor response to chemotherapy compared with tumors with a good response to chemotherapy. We showed that chemotherapy-resistant endometrial cancer cells (ARK1, uterine serous carcinoma and PUC198, grade 3 endometrioid adenocarcinoma) had improved sensitivity and synergy with paclitaxel and carboplatin when treated in combination with AVB-500. We also found that in vivo intraperitoneal models with ARK1 and PUC198 cells had decreased tumor burden when treated with AVB-500 + paclitaxel compared with paclitaxel alone. Treatment with AVB-500 + paclitaxel decreased AKT signaling, which resulted in a decrease in basal glycolysis. Finally, multiple glycolytic metabolites were lower in the tumors treated with AVB-500 + paclitaxel than in tumors treated with paclitaxel alone. Our study provides strong preclinical rationale for combining AVB-500 with paclitaxel in aggressive endometrial cancer models.

Immunosuppressive tumor microenvironment in uterine serous carcinoma via CCL7 signal with myeloid-derived suppressor cells.

Serous carcinoma of the uterus (USC) is a pathological subtype of high-grade endometrial cancers, with no effective treatment for advanced cases. Since such refractory tumors frequently harbor antitumor immune tolerance, many immunotherapies have been investigated for various malignant tumors using immuno-competent animal models mimicking their local immunities. In this study, we established an orthotopic mouse model of high-grade endometrial cancer and evaluated the local tumor immunity to explore the efficacy of immunotherapies against USC. A multivariate analysis of 62 human USC cases revealed that the tumor-infiltrating cell status, few CD8+ cells and abundant myeloid-derived suppressor cells (MDSCs), was an independent prognostic factor (P < 0.005). A murine endometrial cancer cell (mECC) was obtained from C57BL/6 mice via endometrium-specific deletion of Pten and Tp53, and another high-grade cell (HPmECC) was established by further overexpressing Myc in mECCs. HPmECCs exhibited higher capacities of migration and anchorage-independent proliferation than mECCs (P < 0.01, P < 0.0001), and when both types of cells were inoculated into the uterus of C57BL/6 mice, the prognosis of mice bearing HPmECC-derived tumors was significantly poorer (P < 0.001). Histopathological analysis of HPmECC orthotopic tumors showed serous carcinoma-like features with prominent tumor infiltration of MDSCs (P < 0.05), and anti-Gr-1 antibody treatment significantly prolonged the prognosis of HPmECC-derived tumor-bearing mice (P < 0.05). High CCL7 expression was observed in human USC and HPmECC, and MDSCs migration was promoted in a CCL7 concentration-dependent manner. These results indicate that antitumor immunity is suppressed in USC due to increased number of tumor-infiltrating MDSCs via CCL signal.

Rare Subtype of Endometrial Cancer: Undifferentiated/Dedifferentiated Endometrial Carcinoma, from Genetic Aspects to Clinical Practice.

Endometrial cancer (EC) is one of the most common gynecologic cancers worldwide. There were 417,367 newly diagnosed cases and 97,370 deaths due to this disease worldwide in 2020. The incidence rates have increased over time, especially in countries with rapid socioeconomic transitions, and EC has been the most prevalent gynecologic malignancy in Taiwan since 2012. The new EC molecular classifications of The Cancer Genome Atlas (TCGA) Research Network include clear-cell carcinoma, serous carcinoma, and carcinosarcoma, while undifferentiated/dedifferentiated EC (UDEC) is not mentioned, and most previous clinical trials for EC have not included UDEC. UDEC is rare, has an aggressive growth pattern, tends to be diagnosed at an advanced stage, and is resistant to conventional chemotherapy. In this review, case series or case reports on the clinical features and genomic/epigenetic and expression profiles on UDEC data are summarized in order to identify potential molecular targets for current and future research.

The histological type of endometrial cancer is not associated with menopause status at diagnosis.

The latest evidence suggests that type 2 endometrial cancer may not be completely oestrogen-independent, indicating that the status of hormonal change may not be associated with the traditional classification of endometrial cancer, including the histological subtypes. However, this has not been investigated. Menopause is commonly considered a state of hormonal change in women. In the present study, we investigated the association of menopause with the histological types of endometrial cancer. Data on the histological type, menopause status at diagnosis, age at diagnosis, parity, body mass index (BMI), and overall survival rate from 2122 cases were collected. The difference in risk in developing type 1 or type 2 endometrial cancer between premenopausal and postmenopausal patients was 5.457%. A statistical difference in the association of menopause with the histological types between the two groups was seen in endometrioid and serous carcinoma, with a risk difference of 5.6 or 3.8%. A statistical difference in the association of menopause with parity between the groups was only seen in endometrioid and adenosquamous carcinoma, with a risk difference of 7.1 or 3.7%. However, BMI was not associated with histological type and the overall survival rate was not associated with menopause (P=0.764). We reported a relatively small difference in the association of menopause with type 1 or type 2, or the histological types of endometrial cancer. The survival rate was not associated with menopause. Our study suggests that menopause status at diagnosis was not strongly associated with the histological subtypes of endometrial cancer.

300 EGF System receptors status in aggressive subtypes of endometrial cancer

Introduction/Aims: ErbB receptors are trans-membrane glycoproteins with tyrosine kinase activity. Especially in cancer, they are implicated in cell proliferation, transformation, angiogenesis, migration and invasion. The expression of ErbB receptors, has not been studied well in endometrial cancer patients. The main aim of our study was to access EGF system receptors status in aggressive subtypes of endometrial cancer. Methods: We evaluated retrospectively tissue specimens from 10 patients with type II endometrial cancer, that have been treated in Gynaecological Oncology Unit of the University of Patras.

Why do some patients with stage 1A and 1B endometrial endometrioid carcinoma experience recurrence? A retrospective study in search of prognostic factors.

Endometrial endometrioid carcinoma (EEC) is the most encountered subtype of endometrial cancer (EC). Our study aimed to investigate the factors affecting recurrence in patients with stage 1A and 1B EEC. Our study included 284 patients diagnosed with the International Federation of Gynecology and Obstetrics stage 1A/1B EEC in our center from 2010 to 2018. The clinicopathological characteristics of the patients were obtained retrospectively from their electronic files. The median age of the patients was 60 years (range 31-89). The median follow-up time of the patients was 63.6 months (range 3.3-185.6). Twenty-two (7.74%) patients relapsed during follow-up. Among the relapsed patients, 59.1% were at stage 1A ECC, and 40.9% were at stage 1B. In our study, the one-, three-, and five-year recurrence-free survival (RFS) rates were 98.9%, 95.4%, and 92.9%, respectively. In the multivariate analysis, grade and tumor size were found to be independent parameters of RFS in all stage 1 EEC patients. Furthermore, the Ki-67 index was found to affect RFS in stage 1A EEC patients, and tumor grade affected RFS in stage 1B EEC patients. In the time-dependent receiver operating characteristic curve analysis, the statistically significant cut-off values were determined for tumor size and Ki-67 index in stage 1 EEC patients. Stage 1-EEC patients in the higher risk group in terms of tumor size, Ki-67, and grade should be closely monitored for recurrence. Defining the prognostic factors for recurrence in stage 1 EEC patients may lead to changes in follow-up algorithms.

Expression of epigenetic pathway related genes in association with PD-L1, ER/PgR and MLH1 in endometrial carcinoma

The distribution of Endometrial Cancer (EC)-related deaths is uneven among the morphologic subtypes of EC. Serous Cancer (SC) makes 10% of all EC and accounts for 40% of EC-related deaths. We investigated expression of selected genes involved in epigenetic pathways by immunohistochemistry in a cohort of 106 EC patients and analyzed mRNA-based expression levels for the same set of genes in EC samples from The Cancer Genome Atlas (TCGA) dataset. A tissue microarray was constructed using low-grade (n = 30) and high-grade (n = 28) endometrioid, serous (n = 31) and clear cell carcinoma (n = 17) samples. Epigenetic marker levels were associated with PD-L1, ER/PgR, and MLH1 expression. Epigenetic markers were evaluated by H-score and PD-L1 expression was recorded by using Combined Positive Score. Results were correlated with disease stage and survival outcome. BRD4, KAT6a and HDAC9 levels were higher in SC compared to other histologic subtypes (p<0.001–0.038). After adjusting for multiple comparisons, DNMT3b expression was higher in SC compared to endometrioid-type but not between SC and CCC. The expression levels of BRD4 (p = 0.021) and KAT6a (p = 0.0027) were positively associated with PD-L abundance, while PgR (p = 0.029) and PD-L1 expression were negatively associated. In addition, BRD4 expression was low in specimens with loss of MLH1 expression (p = 0.02). More importantly, BRD4 abundance had a negative impact on disease outcome (p = 0.02). Transcriptionally, BRD4, KAT6a and DNMT3b expression levels were higher in SC in TCGA dataset. The median PD-L1 expression was marginally associated with BRD4, a transcriptional activator of CD274/PD-L1 (p = 0.069) and positively with KAT6a (p = 0.0095). In conclusion, the protein expression levels of epigenetic markers involved in cancer pathogenesis are increased by immunohistochemistry in SC. PD-L1 levels are associated with BRD4 and KAT6a in EC samples. A combination therapy with BRD4/PD-L1 or KAT6a/PD-L1 inhibitors might have a potential use in EC, in particular serous-type carcinoma.

Clinicopathologic and protein markers distinguishing the "polymerase epsilon exonuclease" from the "copy number low" subtype of endometrial cancer.

ObjectiveThe need to perform genetic sequencing to diagnose the polymerase epsilon exonuclease (POLE) subtype of endometrial cancer (EC) hinders the adoption of molecular classification. We investigated clinicopathologic and protein markers that distinguish the POLE from the copy number (CN)-low subtype in EC.MethodsNinety-one samples (15 POLE, 76 CN-low) were selected from The Cancer Genome Atlas EC dataset. Clinicopathologic and normalized reverse phase protein array expression data were analyzed for associations with the subtypes. A logistic model including selected markers was constructed by stepwise selection using area under the curve (AUC) from 5-fold cross-validation (CV). The selected markers were validated using immunohistochemistry (IHC) in a separate cohort.ResultsBody mass index (BMI) and tumor grade were significantly associated with the POLE subtype. With BMI and tumor grade as covariates, 5 proteins were associated with the EC subtypes. The stepwise selection method identified BMI, cyclin B1, caspase 8, and X-box binding protein 1 (XBP1) as markers distinguishing the POLE from the CN-low subtype. The mean of CV AUC, sensitivity, specificity, and balanced accuracy of the selected model were 0.97, 0.91, 0.87, and 0.89, respectively. IHC validation showed that cyclin B1 expression was significantly higher in the POLE than in the CN-low subtype and receiver operating characteristic curve of cyclin B1 expression in IHC revealed AUC of 0.683.ConclusionBMI and expression of cyclin B1, caspase 8, and XBP1 are candidate markers distinguishing the POLE from the CN-low subtype. Cyclin B1 IHC may replace POLE sequencing in molecular classification of EC.