Endometrioid Endometrial Cancer Research Articles

Trends in incidence and hormonal management of endometrial cancer during potentially reproductive age in Japan: a population-based study.

We aimed to investigate the trends in the incidence and treatment of endometrial cancer (EC) during potentially reproductive age in Japan, with a special focus on the relative oncologic safety of hormonal therapy (HT) over surgery. This population-based retrospective cohort study was conducted using data from the Osaka Cancer Registry from 2004 to 2018. Women with EC were first identified and then distributions of age, stage, histology, and initial treatment were examined. Then, the relative oncologic safety of HT over surgery in patients under the age of 50years was evaluated. Among the 9417 patients with EC, 1937 were diagnosed during their potentially reproductive age (< 50years). The incidence of EC during potentially reproductive age has increased from 18.5% in 2004-2011 to 21.9% in 2012-2018. ECs during potentially reproductive age more frequently displayed favorable characteristics, such as endometrioid histology, and lower histological grade than those in non-potentially reproductive age. Among the 1223 patients diagnosed with localized endometrioid EC, 74 cases (6.0%) received HT as an initial treatment, while 1100 cases (90.0%) underwent surgery as their initial treatment. When the two treatment groups were compared, there was no significant difference in overall survival (p = 0.3713). The estimated 5-year survival rates were 100 and 98.8% in the HT and surgery groups, respectively. EC is increasingly diagnosed during potentially reproductive age in Japan. The use of HT as an initial treatment is increasing, and achieved comparable survival outcomes to urgery against localized endometrioid EC during the potentially reproductive age.

Predicting the Risk of nOdal disease with histological and Molecular features in Endometrial cancer: the prospective PROME trial.

To assess the role of histopathological and molecular features in predicting the risk of nodal metastases in apparent early-stage endometrial cancer patients undergoing sentinel node mapping. This is a prospective trial. Consecutive patients with apparent early-stage endometrial cancer, undergoing laparoscopic hysterectomy, bilateral salpingo-oophorectomy, and sentinel node mapping, were enrolled. Histological and molecular features were used to predict the node positivity. Charts of 223 apparent early-stage endometrial cancer patients were included in this study. Four (1.8%) patients were excluded from this study due to the lack of data about molecular features. Additionally, nine (4%) patients did not meet the inclusion criteria (due to the presence of peritoneal carcinomatosis or bulky nodes (the presence of p53 abnormality correlated with the presence of advanced stage disease (p<0.001)). The study population included 178 (84.8%) and 32 (15.2%) patients with endometrioid and non-endometrioid endometrial cancer, respectively. According to pathological uterine risk factors, 93 (44.3%), 45 (21.4%), 40 (19.1%), and 32 (15.2%) were classified as low, intermediate, intermediate-high, and high-risk, respectively. Using the surrogate molecular classification, 10 (4.8%), 42 (20%), 57 (27.1%), and 101 (48.1%) were included in the POLE mutated, p53 abnormal, MMRd/MSI-H, and NSMP, respectively. Overall, 41 (19.5%) patients were detected with positive nodes. Molecular features were not associated with the risk of having nodal metastases (OR 1.03, 95% CI 0.21 to 5.05, p=0.969 for POLE mutated; OR 0.788, 95% CI 0.32 to 1.98, p=0.602 for p53 abnormal; OR 1.14, 95% CI 0.53 to 2.42, p=0.733 for MMRd/MSI-H). At multivariable analysis, only deep myometrial invasion (OR 3.318, 95% CI 1.357 to 8.150, p=0.009) and lymphovascular space invasion (OR 6.584, 95% CI 2.663 to 16.279, p<0.001) correlated with the increased risk of positive nodes. Our data suggest that molecular classification does not seem useful to tailor the need of nodal dissection in apparent early-stage endometrial cancer. p53 abnormality predicts the risk of having advanced disease at presentation. Further external validation is needed. NCT05793333.

Caveolin-1‘s dual impact on endometrioid endometrial carcinoma: a histopathological and immunohistochemical study

ABSTRACT The objectives of this study are to evaluate caveolin-1 expression in endometrioid endometrial cancer and its correlation with clinicopathological parameters. Forty-four cases of endometrioid endometrial carcinomas underwent radical hysterectomy. The archived paraffin sections that were stained for caveolin-1 by immunohistochemistry, caveolin-1 expression were detected in cancerous epithelial cells in 18.2% of the cases, and stromal caveolin-1 was detected in 65.9% of the cases. Caveolin-1 expression in the epithelium showed a significant positive association with the T stage and the FIGO stage. Positive caveolin-1 expression in epithelium has a direct, positive and significant relationship with invasion of other organs and a direct and significant relationship with the advanced FIGO stage. As for caveolin-1 expression in the stroma, it showed a significant negative inversely significant association with myometrial invasion. Also, there is a significant negative association between caveolin-1 expression in the epithelium and its expression in the stroma. We conclude that caveolin-1 expression strongly plays a critical role in endometrioid endometrial carcinoma as a tumor suppressor or promoter of invasion. In early lesions, high stromal levels appear to be protective against progression. While decreased stromal expression and increased epithelial expression were associated with aggressive tumors.

Tailoring postoperative management through sentinel lymph node biopsy in low- and intermediate-risk endometrial cancer - the SENTRY clinical trial.

While total hysterectomy and bilateral salpingo-oophorectomy without lymph node staging are standard for low- and intermediate-risk endometrial cancer, certain histopathologic factors revealed after surgery can necessitate additional interventions. Our study assessed the influence of sentinel lymph node biopsy on postoperative decision-making. In the SENTRY trial (July 2021 - February 2023), we enrolled patients with International Federation of Gynaecology and Obstetrics (FIGO) stage IA-IB low-grade endometrioid endometrial cancer. Laparoscopic sentinel lymph node mapping using indocyanine green was performed alongside total hysterectomy with bilateral salpingo-oophorectomy. Subsequent management changes based on sentinel lymph node biopsy results were evaluated. The trial was registered at ClinicalTrials.gov (NCT04972682). Of the 100 enrolled participants, a bilateral detection rate of 91% was observed with a median detection time of 10 min (interquartile range 8-13 min). Sentinel lymph node metastases were found in 8% (N = 8) of participants. Postoperative FIGO staging increased in 15% (N = 15) and decreased in 5% (N = 5) of patients. Sentinel lymph node biopsy results altered the adjuvant treatment plan for 20% (N = 20): external beam radiotherapy was omitted in 12% (N = 12) while 6% (N = 6) had external beam radiotherapy +/- systemic chemotherapy added due to sentinel lymph node metastases. In 2% (N = 2), the external beam radiotherapy field was expanded with the paraaortic region. No intraoperative complications were reported and no 30-day major morbidity and mortality occurred. Throughout a median follow-up of 14 (95% CI 12-15 months, neither patient-reported lymphedema nor pelvic recurrence surfaced in the cohort. Sentinel lymph node biopsy using indocyanine green is a safe procedure and allows tailoring adjuvant therapy in presumed low- and intermediate-risk endometrial cancer. It assists in avoiding external beam radiotherapy overtreatment and introducing additional modalities when necessary.

Is it safe to operate selected low-risk endometrial cancer patients in secondary hospitals?

IntroductionThe aim of this study was to assess the accuracy of a preoperative screening algorithm in identifying low-risk endometrial cancer (EC) patients to ensure optimal care. MethodsA total of 277 patients with primary EC confirmed through biopsy underwent magnetic resonance imaging (MRI). Patients with risk factors for advanced high-risk EC, such as non-endometrioid histology, high-grade differentiation status, deep myometrial invasion, or spread beyond the uterine corpus, were systematically excluded. The remaining preoperatively screened patients with stage IA low-grade endometrioid EC (EEC) (n = 93) underwent surgery in a tertiary hospital. The accuracy of the preoperative diagnosis was evaluated by comparing the findings with the postoperative histopathological results. Disease-free survival (DFS) and overall survival (OS) were analyzed using 8-year follow-up data. ResultsPostoperative histopathological analysis revealed that all patients had grade 1–2 EEC localized to the corpus uteri. Only three patients had deep myometrial invasion (stage IB), but they remained disease-free after 6–9 years of follow-up. The median follow-up time for all patients was 8.7 years. The DFS was 7.6 years, and the OS was 8.6 years. Two patients with stage IA grade 1 EEC experienced relapse and, despite treatment, died of EC. No other EC-related deaths occurred. ConclusionsThe screening algorithm accurately identified low-risk EC patients without compromising survival. Therefore, the algorithm appears to be feasible for selecting patients for surgery in secondary hospitals.

Single-cell transcriptomics reveals comprehensive microenvironment and highlights the dysfuntional state of NK cells in endometrioid carcinoma.

Endometrioid endometrial cancer (EEC) is one of the most common gynecologic malignancies. The interaction between cancer cells and the cells in the tumor microenvironment (TME) plays a crucial role in determining disease progression and response to treatment. To better understand the diversity in the TME of ECC, we conducted a comprehensive analysis using single-cell RNA sequencing across 21 samples, including 16 ECC and 5 adjacent normal tissues. We primarily focused on tumor-infiltrating natural killer (NK) cells and their cell-cell interactions with other immune cell types. We identified a CD56dim_DNAJB1 NK cells subset, which had low cytotoxic capability and high stress levels, suggesting a dysfunctional state. This subset showed strong interactions with tumor-associated macrophages through several ligand-receptor pairs. Additionally, we observed that tumor-infiltrating LAMP3+ dendritic cells may inhibit CD8+ T cells or attract regulatory T cells to the tumor area. These dendritic cells also had impaired activation effects on NK cells within the TME. Our study provides valuable insights into the role of NK cells in cancer immunity and highlights the potential of targeting specific NK cell subsets for therapeutic purposes.

Clinicopathological Implications of Mismatch Repair Status in Endometrioid Endometrial Cancer in Duhok City.

DNA mismatch repair (MMR) is a specialized system that corrects errors in DNA replication, namely, base substitution mismatches and minor insertion-deletion mismatches. The deficient mismatch repair (d-MMR) protein plays a vital role in predicting the prognosis of endometrioid carcinoma. The study aimed to determine the prevalence of MMR errors in endometrial cancer (EC) and their correlation with clinicopathological features. We examined the immunohistochemistry presence of four MMR proteins in 50 samples of EC tissues that were preserved in formalin and embedded in paraffin. The proteins identified were MutL homolog 1 (MLH1), post-meiotic segregation increased 2 (PMS2), MutS homolog 2 (MSH2), and MutS homolog 6 (MSH6). The study examined several clinicopathological characteristics and conducted MMR phenotyping. The findings revealed that among the 50 cases of EC, 40% of patients had grade I disease and 78% had stage I malignancy. Furthermore, among the 50 individuals evaluated, 56% exhibited competence in MMR, whereas 44% displayed loss in nuclear expression of MMR. The rate of MLH1 and PMS2 protein loss was recorded as the greatest, at 18%, while the loss of MSH2 and MSH6 was documented at 6%. Within the same range, the majority of patients with d-MMR were above the age of 50 years. The majority of the recruited EC patients in this study showed advanced age and a high percentage of d-MMR status.

Abstract 4126: The inhibitory effect of statins on distant metastasis and recurrence of endometrial cancer

Abstract Endometrial cancer (EC) is the most common gynecologic malignancy. The most common histological type is endometrioid endometrial cancer (EEC). While the majority of patients present with early-stage and low-grade EEC and have an excellent prognosis, a subset develops distant recurrence derived from EEC after initial treatment of the primary. However, the exact mechanism of distant metastasis and recurrence from EEC is still unclear. In addition, the lack of suitable pre-clinical models is a significant barrier to research for distant metastasis and recurrent cancer derived from EEC. Our preclinical EEC model, the ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/fPtenf/f; Mig-6d/dPtend/d), dramatically accelerates the development of EEC compared to single ablation of either gene. The ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/f Ptenf/f; Mig-6d/dPtend/d mice) displayed distant metastases into the ovary, diaphragmatic skeletal muscle, lymph node, and lung. However, the Ptend/d mice exhibited endometrial cancer without distant metastases. After hysterectomy of EEC confined to uterus, Mig-6d/dPtend/d mice exhibited recurrent EEC in abdomen and lung. To identify prognostic factors for distant metastatic and recurrent EEC, we performed transcriptomic analysis in endometrial hyperplasia, a precancerous condition, from Ptend/d and Mig-6d/dPtend/d mice. Our transcriptomic analysis identified that cholesterol biosynthesis was the most significantly activated pathway in Mig-6d/dPtend/d mice compared to Ptend/d mice. Statins, also known as HMG-CoA reductase inhibitors, are the most common cholesterol-lowering drugs. We evaluated the effect of atorvastatin on tumorigenesis and recurrence of EEC. Mig-6d/dPtend/d mice treated with atorvastatin displayed significant reduction of tumor size compared to vehicle treated group. For vehicle-treated group, our pathological analysis revealed EEC outside the uterus, therefore EEC had disseminated to involve the ovary, diaphragmatic skeletal muscle, lymph node, and lung. However, EEC was confined to the uterus in the atorvastatin treated group. Furthermore, atorvastatin treatment reduced the rate of recurrent EEC development. This data demonstrated that atorvastatin has a remarkable inhibitory effect on metastasis and recurrence of EEC in Mig-6d/d Ptend/d mice. Our results suggest that statins suppress development of distant metastasis and recurrence in mouse models of EEC with Pten and Mig-6 deficiency by inhibiting cholesterol biosynthesis. Citation Format: Keun Cheon Kim, Jung Yoon Yoo, Russell R Broaddus, Eunhee M Jeong, Mark I Hunter, Tae Hoon Kim, Jae-Wook Jeong. The inhibitory effect of statins on distant metastasis and recurrence of endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4126.

Abstract 7563: Efficacy of JPI-547, novel dual PARP inhibitor, in endometrial cancer cell line

Abstract Objectives: PARP inhibitor is effective in treating DNA repair deficiency endometrial cancer. Endometrial cancer (EC) is one of the most common gynecological cancers in developed countries and its incidence is increasing, and the prognosis of patients with early stage and low-risk EC is very good, but the prognosis of progressive and recurrent EC is poor. Novel PARP inhibitor JPI-547 is a PARP and tankyrase dual inhibitor, and in cancer cells, tankyrase inhibitor plays an important role in DNA repair, telomere maintenance, and cell survival. This experiment was conducted to determine whether the reactivity of the PTEN mutant EEC was increased by using the Novel PARP inhibitor. Method: Human endometrioid endometrial cancer cell lines, Hec-1A, Hec-1B and Ishikawa were obtained. Cell viability assay for the drugs Olaparib and JPI-547 were assessed. Colonies consisting of at least 50 cells were counted. The number of dead cells was counted in five different areas of the hemocytometer, and the experiment was performed three times. The percentage of dead cells was analyzed compared to the untreated group. We confirmed the efficacy by siRNA transfection and immunofluorescence. Result: When treated with Olaparib, there was no change in cell viability in the rest of the cells except for Ishikawa cells, which are PTEN mutations. It decreased by 35.4% in Ishikawa cells, whereas when treated with JPI-547, all cell lines Hec-1A, Hec-1B, and Ishikawa cell viability decreased by 28%, 34.3%, and 48.7%, respectively. PTEN knock-down reduced cell visibility by 28% when treated with olaparib, whereas when treated with JPI-547, Hec-1A (siCont) and Hec-1A (siPTEN) decreased by 26% and 42%, respectively, in all cells regardless of whether PTEN knock-down is present. When treated with Olaparib, dead cells were identified only in PTEN knock-down cells, increasing by 22%. When treated with JPI-547, dead cells increased by 25.5% and 33% in all cells of Hec-1A (siCont) and Hec-1A (siPTEN), respectively. It was confirmed that JPI-547 can reduce cell viability regardless of the formation of Rad51 according to PTEN. Conclusion: JPI-547, a novel PARP inhibitor, showed good efficacy in PTEN mutation and PTEN-wild-type EEC cell lines than in conventional PARP inhibitor. The effect of reducing survival of ECC cell line with JPI-547 was confirmed with or without PTEN mutation. Further evaluation and in vivo experiments are needed to prove the efficacy of JPI-547 in EC. Citation Format: Shin-Wha Lee, So-Hyun Nam, Su-Bin Park. Efficacy of JPI-547, novel dual PARP inhibitor, in endometrial cancer cell line [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7563.

Abstract 6416: Early stage endometrioid endometrial cancer recurrence risk stratification using a machine learning RNA-seq gene expression signature

Abstract Endometrioid endometrial cancer (EEC) adjuvant therapy decisions rely on risk stratification using histology, grade, stage, and lymphovascular space invasion (LVSI). Recently, molecular classification systems originating from TCGA, evaluated in GOG-210 and PORTEC-3 defined four prognostic subtypes based on POLE, MSI-H/MMR-D, and p53 alterations. Although valuable, this molecular approach still has significant limitations such as applicability to the majority of EEC patients categorized as no-specific molecular profile (NSMP) and the potential need to resolve pathogenic and prognostic heterogeneity within MMR-D, and TP53 subtypes. These unmet needs were key motivators for Tempus to develop a molecular classifier predicting distant recurrence risk in early-stage EEC with a focus on high intermediate-risk (HIR) patients. The RNA-seq-based gene expression profiler (GEP) was trained using a machine-learning pipeline with TCGA data which resulted in a 24 gene signature that classifies EEC patients as molecular risk (MR) high or low (MR-high, MR-low). The GEP MR test was then evaluated on a de-identified cohort of EEC patients (N=1037) from Tempus to test associations with known pathologic or molecular prognostic features. The GEP-MR risk predictor showed significant enrichment of MR high-risk in G3 versus G1/2 histology (p-value &amp;lt; 5e-8). A high correlation was found between the MR score and copy number alteration score (t-test p-value &amp;lt; 1e-5). Next, a clinical evaluation was performed in an early-stage EEC case-control cohort of patients with documented recurrence or no recurrence event at four years (N=109), from Stanford. In the entire cohort, the MR-high group had a significantly higher rate of distant recurrence in comparison to the MR-low group (HR=4.8, N=109). Next, we performed a subgroup analysis in the clinically important HIR patients. In this subgroup, the MR-high group had a significantly higher rate of distant recurrence in comparison to the MR-low group (HR=8.0, N=56). Lastly, given the significance of genomic biomarkers in the evolution of EEC FIGO staging, we stratified outcomes by the established TCGA subtypes as a reference standard and performed a subgroup analysis in patients classified as having no specific molecular profile (NSMP). Among patients who were NSMP, the MR-high group showed a significantly higher rate of distant recurrence in comparison to the MR-low group (HR=7.92, N=67). These evaluation studies demonstrate the performance of the GEP MR test in early-stage EEC distant recurrence risk stratification, specifically HIR patients, necessitating further studies to validate the test for clinical use in informing adjuvant clinical management. Citation Format: Rafi Pelossof, Talal Ahmed, Seung Won Hyun, Chithra Sangali, Ben Terdich, Calvin Chao, Michael Toboni, Casey Cosgrove, Elizabeth Kidd, Brook Howitt, Timothy Taxter. Early stage endometrioid endometrial cancer recurrence risk stratification using a machine learning RNA-seq gene expression signature [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6416.

Abstract 2168: Intermittent fasting in combination with carboplatin in a pre-clinical model of obesity-driven endometrial cancer

Abstract Objectives: Endometrial cancer (EC) incidence and mortality continue to rise, with obesity a well-known driver of this disease. Obesity is associated with excess estrogen, hyperinsulinemia, activation of the Akt/mTOR pathway, chronic inflammation, and a heightened capacity to harvest dietary energy, all of which contribute to the development and progression of EC. Intermittent energy restriction (IER) is thought to have anti-tumorigenic benefits and has been shown to have synergistic effects with chemotherapy and hormonal therapy in various cancer types. Thus, we evaluated the anti-tumorigenic effects of a switch from high fat diet (HFD) to either IER or low fat diet (LFD) with carboplatin treatment in a mouse model of obesity-driven endometrioid EC. Methods: Lkb1fl/flp53fl/fl mice were fed either HFD or LFD starting at 4 weeks of age. At 12 weeks of age, the HFD-fed mice were randomized to three treatment groups: continuous HFD, HFD-LFD switch, and HFD-IER switch. The LFD-fed mice were continuously maintained on LFD. At 16 weeks of age, all mice were injected with AdCre into the left uterine horn to induce EC development. At 26 weeks of age, mice were treated with placebo or carboplatin (50 mg/kg intraperitoneally weekly) for 4 weeks (n=8-10 mice per group). EC incidence, tumor weight, and body weight were evaluated. EC gene expression was assessed by microarray analysis. Results: EC incidence was lowest in the HFD-IER group (~60%) and highest in the HFD group (~80%); rates were similar in the other diet groups (~75%). The continuous HFD-fed mice demonstrated a 76% increase in tumor size relative to continuous LFD-fed mice (p&amp;lt;0.001). At sacrifice and after carboplatin treatment, mean body weights were significantly higher (p&amp;lt;0.05) in the HFD group (38g) than groups receiving continuous LFD (26g), HFD-LFD switch (28g), or HFD-IER switch (21g), although mean body weights were not significantly different within diet groups between placebo and carboplatin-treated mice. In placebo-treated groups, mean tumor weights were significantly lower in mice fed continuous LFD (0.62g), HFD-LFD switch (0.60g) and HFD-IER switch (0.26g) relative to continuous HFD-fed mice (1.10 g; p&amp;lt;0.001). When comparing gene expression between the HFD-LFD and the HFD-IER placebo groups, genes related to cholesterol metabolism, estrogen response, and inflammation were preferentially up-regulated in the HFD-IER group. Carboplatin treatment reduced EC tumor size 42-69% across all diet groups (p&amp;lt;0.05); tumor size was the smallest in the HFD-IER group (0.15g) relative to mice receiving continuous HFD (0.34g), HFD-LFD (0.29g) or continuous LFD (0.34g). Conclusion: IER with carboplatin treatment may be an innovative combination treatment strategy in the management of EC, a highly obesity-driven cancer. Citation Format: Jennifer Haag, Olivia Lara, Chunxiao Zhou, Stephen D. Hursting, Victoria Bae-Jump. Intermittent fasting in combination with carboplatin in a pre-clinical model of obesity-driven endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2168.

Incidence of sentinel lymph node metastases in apparent early-stage endometrial cancer: a multicenter observational study

ObjectiveUltrastaging is accurate in detecting nodal metastases, but increases costs and may not be necessary in certain low-risk subgroups. In this study we examined the risk of nodal involvement detected...

Molecular and pathologic data to guide selection of patients with endometrioid endometrial cancer for ovarian preservation

ObjectivesTo investigate the association of molecular and pathologic factors with concurrent or recurrent ovarian disease to guide ovarian preservation in endometrioid endometrial cancer.MethodsPatients with endometrial cancer ≤50 years of age...

Prognostic evaluation of lymph-vascular space invasion in patients with endometrioid and non-endometrioid endometrial cancer: A multicenter study

IntroductionThe prognostic value of lymph-vascular space invasion (LVSI) on endometrial cancer (EC) remains controversial. This study aimed to explore the impact of LVSI on patients with endometrioid and non-endometrioid EC in China. Materials and methodsWe analyzed EC patients who underwent surgery from 2010 to 2019 in seven Chinese hospitals retrospectively and stratified patients based on histopathologic types and LVSI status. Endpoints were disease-free survival (DFS) and overall survival (OS). Propensity score matching (PSM) algorithm was used to balance the confounding factors. The survival was examined using Kaplan-Meier analysis. Cox proportional hazards regression analyses were used to find prognostic independent risk factors. ResultsAmong 3715 EC patients, LVSI positive rate was 9.31% (346/3715). After matching, LVSI present group had shorter DFS (P = 0.005), and similar OS (P = 0.656) than LVSI absent group for endometrioid EC patients. For non-endometrioid EC patients, there was no statistical difference in either DFS (P = 0.536) or OS (P = 0.512) after matching. The multivariate Cox analysis showed that LVSI was an independent risk factor of DFS [hazard ratio (HR) 2.62, 95% confidence intervals (CI) 1.35–5.10, P = 0.005] and not OS (HR 1.24, 95%CI 0.49–3.13, P = 0.656) for endometrioid EC patients. It was not a prognostic factor of either DFS (HR 1.28, 95%CI 0.58–2.81, P = 0.539) or OS (HR 1.33, 95%CI 0.55–3.13, P = 0.515) for non-endometrioid EC patients. ConclusionLVSI is an adverse prognostic factor for endometrioid EC patients and has no impact on non-endometrioid EC patients. Necessity of postoperative adjuvant therapy based on LVSI needs to be carefully considered for non-endometrioid EC patients.

Where Morphological and Molecular Classifications Meet: The Role of p53 Immunohistochemistry in the Prognosis of Low-Risk Endometrial Carcinoma (GLAMOUR Study).

No prospective study has validated molecular classification to guide adjuvant treatment in endometrial cancer (EC), and not even retrospective data are present for patients with morphological low-risk EC. We conducted a retrospective, multicenter, observational study including 370 patients with low-risk endometrioid EC to evaluate the incidence and prognostic role of p53 abnormal expression (p53abn) in this specific subgroup. Among 370 patients, 18 had abnormal expressions of p53 (4.9%). In 13 out of 370 patients (3.6%), recurrences were observed and two were p53abn. When adjusting for median follow-up time, the odds ratio (OR) for recurrence among those with p53abn versus p53 wild type (p53wt) was 5.23-CI 95% 0.98-27.95, p = 0.053. The most common site of recurrence was the vaginal cuff (46.2%). One recurrence occurred within the first year of follow-up, and the patient exhibited p53abn. Both 1-year and 2-year DFS rates were 94.4% and 100% in the p53abn and p53wt groups, respectively. One patient died from the disease and comprised p53wt. No difference in OS was registered between the two groups; the median OS was 21.9 months (16.4-30.1). Larger multicenter studies are needed to tailor the treatment of low-risk EC patients with p53abn. Performing molecular classification on all EC patients might be cost-effective, and despite the limits of our relatively small sample, p53abn patients seem to be at greater risk of recurrence, especially locally and after two years since diagnosis.

Differences in single gene expression patterns and signaling pathways between Black and White patients in high grade endometrioid endometrial cancer independent of BMI

ObjectiveEndometrial cancer (EC) incidence and mortality are increasing with striking racial disparities. Race and obesity are known risk factors for EC, however, their relationship and impact on tumor biology in higher grade endometrioid EC are unclear. The objective of this pilot study was to identify gene- and pathway-level changes in tumors from Black patients compared to White, both in general and in the context of dichotomized BMI. MethodsA single institution retrospective convenience sample was obtained for grade 2 or 3 endometrioid EC, equally distributed amongst Black and White patients. Tumor samples were analyzed with the Tempus Laboratories xT NGS-based genome profiling test. DESeq2 was applied to identify differentially expressed genes, and then subjected to ingenuity pathway analysis (IPA). Continuous variables were analyzed using unpaired t-tests, and categorical using Chi-squared and Fisher exact tests. Results39 representative cases were identified and analyzed from 2006 to 2021. Baseline clinicopathologic characteristics were similar. 157 genes were differentially expressed in tumors from Black patients compared to White regardless of BMI. IPA identified 81 significantly different pathways between Black and White patients with a BMI < 40 kg/m2, and 117 with a BMI ≥ 40 kg/m2. Of these, eleven pathways were consistently and significantly activated or deactivated regardless of BMI. ConclusionDifferences in gene expression and pathway activation in EC exist between race and BMI, which highlights the need for further research to better understand the implications of these differences on endometrioid EC progression, outcomes, and treatment in this historically underserved patient population.

Abstract B024: Immune exhaustion and reversal of progestin-related immune modulation in adaptive resistance to levonorgestrel intrauterine device for treatment of atypical hyperplasia and early endometrial cancer

Abstract Background: A growing proportion of women diagnosed with atypical hyperplasia (AH) and early-stage endometrioid endometrial cancer (EEC) require nonsurgical treatment options. Our previously published phase II clinical trial of the levonorgestrel intrauterine device (LIUD) for AH and grade 1 EEC (G1EEC) demonstrated 83% response rate at 1 year; however, prospective long-term follow-up data and determinants for duration of response to LIUD are limited. Methods: Follow-up data from patients that participated in our prospective phase II trial of LIUD as a nonsurgical approach for AH and G1EEC were collected from medical records. Duration of response and time to relapse were evaluated. Spatial transcriptomic profiling from longitudinal biopsy samples from pre-treatment (n=5), on-treatment (n=5), and disease relapse lesions (n=3) were evaluated using digital spatial profiling (DSP, Nanostring GeoMX Whole Transcriptome Atlas). In silico cell type deconvolution was performed and pathway analyses was conducted using gene set variation analysis enrichment. Results: Of 43 participants exhibiting initial response to LIUD, 41 had follow-up data. Sixteen experienced disease relapse (39%) with a median time to relapse of 17 months after initial response. Clinical factors associated with shorter duration of response included age (HR 0.95, p=0.021), initial diagnosis of G1EEC (HR 3.51, p=0.014), premenopausal status (HR 3.85, p=0.039), and Hispanic ethnicity (HR 3.45, p=0.017). Pre-treatment IGF1 and IGF2 expression levels were positive predictors of duration of response (HR 0.44 and 0.45, respectively, p&amp;lt;0.05). DSP results revealed that LIUD increased NK cells (log2FC=46.13, FDR=0.004), and lymphocyte cytotoxicity signaling markers GZMB (log2FC=1.06, padj=0.023) and PRF1 (log2FC=1.62, padj=0.004), but NK cells were reduced in relapse lesions (log2FC=-55.96, FDR=0.02) as was PRF1 expression (log2FC=-1.87, padj=0.038). Multiple immune-related pathways (IFNα and IFNγ response, TGFβ signaling) were significantly upregulated in relapse lesions compared to matched pre-treatment lesions (FDR&amp;lt;0.05). IDO1 expression, a marker for immune exhaustion, was upregulated in relapse lesions compared to matched pre-treatment and on-treatment lesions (log2FC=2.56, FDR=0.01). Conclusions: While LIUD for treatment of AH or G1EEC has excellent initial response rates, upfront resistance, and relapse after initial response to LIUD impacts nearly half of patients. Our study shows progestin-related immunomodulatory effects, including increased NK cell infiltration and lymphocyte cytotoxicity. Immune mechanisms for relapse are implicated here, including reversal of progestin-related immunomodulatory effects (decreased NK cell infiltration and lymphocyte cytotoxicity) and increased immune exhaustion (prolonged IFNα and IFNγ response and increased IDO1 expression in relapse lesions). Thus, relieving immune exhaustion may increase durability of response to LIUD for treatment of AH or G1EEC. Citation Format: Mikayla B. Bowen, Brenda Melendez, Qian Zhang, Richard Yang, Bryan Fellman, Barrett Lawson, Naomi Adjei, Joseph Celestino, Tri Nguyen, Khalida Wani, Bhavana Singh, Christof Straub, Liang Zhang, Cheryl Tan, Felicia New, Diana Urbauer, Alexander Lazar, Karen Lu, Jennifer Wargo, Shannon N. Westin, Melinda S. Yates. Immune exhaustion and reversal of progestin-related immune modulation in adaptive resistance to levonorgestrel intrauterine device for treatment of atypical hyperplasia and early endometrial cancer [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr B024.

Abstract B004: Investigating loss of ARID1A protein on endometrial cancer progression through the destabilization of adherens junctions

Abstract The purpose of this work is to test the hypothesis that loss of ARID1A promotes endometrial cancer progression by destabilizing tumor cell adherens junctions proteins. ARID1A, an important structural subunit of the SWI/SNF chromatin remodeling complex, is mutated in 26-39% of endometrioid tumors. In endometrial cancer loss of ARID1A has been classically linked to loss of ARID1A expression and has been shown to correlate with increasing tumor grade. However, little is known about the functional impact of ARID1A loss on endometrial cancer progression. A common hallmark of aggressive endometrial cancer is decreased membranous expression of adherens junction proteins, E-Cadherin and β-Catenin. In colorectal and gastric cancer loss of ARID1A expression has been shown to directly downregulate E-Cadherin expression. To determine how loss of ARID1A affects adherens junctions and its impact on endometrial cancer progression we utilized human endometrial cancers and human endometrial cancer cell lines. Using immunohistochemistry, we determined the expression and localization of ARID1A and the adherens junction protein β-Catenin in forty-six human endometrioid type endometrial cancers. Intratumoral heterogeneity of ARID1A expression allowed for quantification of membranous E-Cadherin in relation to presence or absence of ARID1A protein within the same human endometrial tumor. To quantify membranous E-Cadherin we performed immunofluorescence and used line intensity measurements in intratumoral areas of ARID1A presence and ARID1A absence. To assess effects of ARID1A loss on adherens junction in vitro we used short-hairpin RNA to acutely knockdown ARID1A in the endometrial cancer cell lines Ishikawa and ECC-1. Protein expression of ARID1A and E-Cadherin in ARID1A knockdown cells was assessed by Western Blot. Within our cohort of forty-six human endometrial tumors, 75% of tumors with wild-type ARID1A and 45% of tumors with mutated ARID1A had absence of ARID1A protein expression. Due to the discordance between presence of an ARID1A gene mutation and the expression of ARID1A protein, we hypothesize that there are alternative mechanisms of ARID1A protein regulation in endometrial cancer. Additionally, tumors with loss of ARID1A show a trend towards nuclear localization of β-Catenin and have a significant decrease in membranous E-Cadherin expression (P&amp;lt;0.001). However, acute knockdown of ARID1A in Ishikawa and ECC-1 human endometrial cancer cells does not affect total E-Cadherin protein. This suggests that loss of ARID1A may decrease adherens junction stability, as decreased membranous expression of E-Cadherin without total protein change is a common phenotype of destabilized adherens junctions. Thus, we hypothesize that loss of ARID1A destabilizes adherens junctions leading to increased endometrial tumor aggression. Citation Format: Savannah E. Wright, Isurika Weerasinghe, Russell R. Broaddus, Andrew B. Gladden. Investigating loss of ARID1A protein on endometrial cancer progression through the destabilization of adherens junctions [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr B004.

Abstract IA002: Management of newly diagnosed endometrial cancers and molecular classification

Abstract In the past 50 years, the treatment of this cancer has evolved from a regimen of preoperative radiation therapy followed by hysterectomy, to individualized management consisting of surgical treatment with or without additional therapy depending on whether various risk factors are identified. After the diagnosis of endometrial carcinoma has been histologically confirmed, uterine and extrauterine risk factors affect the probability of retroperitoneal lymph node involvement and subsequent survival. Surgical staging is a critical component for the proper diagnosis and management of all endometrial carcinomas. FIGO stage is the most powerful predictor of prognosis. Surgical staging is feasible by minimally invasive techniques. Patients with significant medical comorbidities who are not acceptable candidates for surgery may be managed by alternative means. Women with EC are diagnosed under the age of 40 may be eligibile for nonoperative management if there is no clear evidence of myometrial invasion. As the contemporary management of EC continues to evolve, and the indications for lymph node dissection remain controversial. Minimally invasive management of EC has increasingly been integrated into standard practice. In 2006, The Cancer Genome Atlas (TCGA) began with studies in glioblastoma and high-grade serous ovarian cancer. The National Institutes of Health committed major resources to TCGA to collect and characterize the genomic landscape of more than 20 cancer types. In 2013, TCGA published findings for endometrial cancers. Only serous and endometrioid subtypes were accrued in the endometrial cancer project. TCGA has reclassified endometrioid and serous endometrial cancers in four broad categories using comprehensive genomic approaches. One-third of the cancers is characterized by microsatellite instability (MSI) and associated hyper-mutation. The cancers without MSI can be further separated into two groups. Serous cases with extensive DNA copy number alterations and genomic instability comprise one group, and endometrioid cases with few or only focal copy number alterations comprise the other. A smaller fourth sub-group contains samples with very high mutation rates and is characterized by mutations in POLE. Molecular features can be distinctly overlaid onto these four sub-classifications, and each have important clinical implications that are currently being used in both clinical practice and clinical trial design. In this educational presentation, we will discuss the management of newly diagnosed endometrial cancers, review the molecular classification of endometrial cancers, and identify approaches that incorporate these findings into clinical care and clinical trial design. Citation Format: Douglas A. Levine. Management of newly diagnosed endometrial cancers and molecular classification [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr IA002.

Abstract A018: A phase 2, open-label, single-arm, prospective, multicenter study of nab-sirolimus plus letrozole in advanced or recurrent endometrioid endometrial cancer

Abstract Introduction/Objective: This trial in progress is designed to evaluate the anti-tumor activity of nab-sirolimus in combination with letrozole in patients with advanced or recurrent endometrioid endometrial carcinoma (EEC). Despite recent pivotal data demonstrating improved outcomes with immunotherapy plus chemotherapy, regardless of mismatch repair status, alternative treatment options, particularly for advanced or recurrent EEC remain necessary. Dysregulation of mammalian target of rapamycin (mTOR) signaling is implicated in the pathology of EEC, in which &amp;gt;80% harbor PTEN or PI3K/AKT/mTOR pathway alterations. Moreover, crosstalk between mTOR and estrogen receptor signaling pathways is associated with endocrine resistance. GOG-3007 and other phase 2 studies have demonstrated that the combination of conventional mTOR inhibitors (mTORis) and endocrine therapy provides clinical benefit in patients with EC. nab-Sirolimus, a nanoparticle injectable form of mTORi, is approved in the USA for malignant perivascular epithelioid cell tumor. Preclinical data of nab-sirolimus demonstrated improved tumor accumulation, mTOR inhibition, and tumor growth suppression compared with conventional mTORis. We hypothesize that nab-sirolimus in combination with letrozole may produce synergistic antitumor activity in patients with recurrent EEC. Methods: In this phase 2, open-label, single-arm, multicenter study (NCT05997017), nab-sirolimus (100 mg/m2, intravenous, on days 1 and 8 of each 21-day cycle) and letrozole (2.5 mg, oral, daily) are administered to patients (~29 planned) with clinically confirmed, advanced, or recurrent EEC. Eligibility criteria include age ≥18 years, ≤1 prior chemo-based regimen, Eastern Cooperative Oncology Group performance status score 0 or 1, naïve to mTORi, and measurable disease (per Response Evaluation Criteria in Solid Tumors [RECIST] v1.1). The primary endpoint is best overall response rate by RECIST v1.1. Key secondary endpoints include duration of response, progression-free survival, overall survival, and safety. The relationship between biomarkers and response outcomes is an exploratory endpoint. Citation Format: Lauren E. Dockery, Anna Priebe, Linda Duska, Angela K. Green, Cara Mathews, Fernanda Musa, David O'Malley, Allison Puechl, Li Ding, Anita N. Schmid, Willis H. Navarro, Brian Slomovitz, Kathleen Moore. A phase 2, open-label, single-arm, prospective, multicenter study of nab-sirolimus plus letrozole in advanced or recurrent endometrioid endometrial cancer [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr A018.