Characterization of mismatch-repair/microsatellite instability-discordant endometrial cancers.

BACKGROUND: Mismatch-repair (MMR)/microsatellite instability (MSI) status has therapeutic implications in endometrial cancer (EC). The authors evaluated the concordance of testing and factors contributing to MMR expression heterogeneity. METHODS: Six hundred sixty-six ECs were characterized using immunohistochemistry (IHC), MSI testing, and mut-L homolog 1 (MLH1) methylation. Select samples underwent whole-transcriptome analysis and next-generation sequencing. MMR expression of metastatic/recurrent sites was evaluated. RESULTS: MSI testing identified 27.3% of cases as MSI-high (n = 182), MMR IHC identified 25.1% cases as MMR-deficient (n = 167), and 3.8% of cases (n = 25) demonstrated discordant results. A review of IHC staining explained discordant results in 18 cases, revealing subclonal loss of MLH1/Pms 1 homolog 2 (PMS2) (n = 10) and heterogeneous MMR IHC (mut-S homolog 6 [MSH6], n = 7; MLH1/PMS2, n = 1). MSH6-associated Lynch syndrome was diagnosed in three of six cases with heterogeneous expression. Subclonal or heterogeneous cases had a 38.9% recurrence rate (compared with 16.7% in complete MMR-deficient cases and 9% in MMR-proficient cases) and had abnormal MMR IHC results in all metastatic recurrent sites (n = 7). Tumors with subclonal MLH1/PMS2 demonstrated 74 differentially expressed genes (determined using digital spatial transcriptomics) when stratified by MLH1 expression, including many associated with epithelial-mesenchymal transition. CONCLUSIONS: Subclonal/heterogeneous MMR IHC cases showed epigenetic loss in 66.7%, germline mutations in 16.7%, and somatic mutations in 16.7%. MMR IHC reported as intact/deficient missed 21% of cases of Lynch syndrome. EC with subclonal/heterogeneous MMR expression demonstrated a high recurrence rate, and metastatic/recurrent sites were MMR-deficient. Transcriptional analysis indicated an increased risk for migration/metastasis, suggesting that clonal MMR deficiency may be a driver for tumor aggressiveness. Reporting MMR IHC only as intact/deficient, without reporting subclonal and heterogeneous staining, misses opportunities for biomarker-directed therapy. PLAIN LANGUAGE SUMMARY: Endometrial cancer is the most common gynecologic cancer, and 20%-40% of tumors have a defect in DNA proofreading known as mismatch-repair (MMR) deficiency. These results can be used to guide therapy. Tests for this defect can yield differing results, revealing heterogeneous (mixed) proofreading capabilities. Tumors with discordant testing results and mixed MMR findings can have germline or somatic defects in MMR genes. Cells with deficient DNA proofreading in tumors with mixed MMR findings have DNA expression profiles linked to more aggressive characteristics and cancer spread. These MMR-deficient cells may drive tumor behavior and the risk of spreading cancer.

Tissue factor as a novel diagnostic target for early detection of ovarian cancer using ultrasound microbubbles.

INTRODUCTION: Ovarian cancer (OC) is the deadliest gynecologic malignancy, with an overall 5-year survival rate of less than 30%. The existing paradigm for OC detection involves a serum marker, CA125, and ultrasound examination, neither of which is sufficiently specific for OC. This study addresses this deficiency through the use of a targeted ultrasound microbubble directed against tissue factor (TF). METHODS: TF expression was examined in both OC cell lines and patient-derived tumor samples via western blotting and IHC. In vivo microbubble ultrasound imaging was analyzed using high grade serous ovarian carcinoma orthotopic mouse models. RESULTS: While TF expression has previously been described on angiogenic, tumor-associated vascular endothelial cells (VECs) of several tumor types, this is first study to show TF expression on both murine and patient-derived ovarian tumor-associated VECs. Biotinylated anti-TF antibody was conjugated to streptavidin-coated microbubbles and in vitro binding assays were performed to assess the binding efficacy of these agents. TF-targeted microbubbles successfully bound to TF-expressing OC cells, as well as an in vitro model of angiogenic endothelium. In vivo, these microbubbles bound to the tumor-associated VECs of a clinically relevant orthotopic OC mouse model. CONCLUSION: Development of a TF-targeted microbubble capable of successfully detecting ovarian tumor neovasculature could have significant implications towards increasing the number of early-stage OC diagnoses. This preclinical study shows potential for translation to clinical use, which could ultimately help increase the number of early OC detections and decrease the mortality associated with this disease.

Glassy cell carcinoma of the cervix: Findings from a combined National Cancer Database analysis and single institution review of treatment patterns and outcomes.

OBJECTIVES: To describe stage, treatment patterns, and survival for glassy cell carcinoma of the cervix (GCCC), a poorly understood rare tumor. METHODS: Clinical data and survival were compared between GCCC and more common histologic types using the National Cancer Database (NCDB) from 2004 to 2017. A retrospective review of GCCC cases at our institution from 2012 to 2020 was simultaneously performed with staging updated according to 2018 FIGO staging. Descriptive statistics and survival analyses were performed, and outcomes compared to historical references. RESULTS: 143/89,001 (0.16%) NCDB cervical cancer cases were GCCC. Compared to other histologies, GCCC cases were younger, with 74.8% diagnosed before age 50. Stage distribution was similar. Stage I cases were less commonly treated with surgery alone (19/69, 27%). 79.4% of locally advanced (stage II-IVA) cases were treated with definitive chemoradiation. GCCC demonstrated worse OS for early-stage and locally-advanced disease. No survival differences were observed for patients with stage IVB disease. Our institutional review identified 14 GCCC cases. Median age at diagnosis was 34 years. All nine early-stage cases underwent radical hysterectomy. Adjuvant radiation was given for cases meeting Sedlis criteria (4/9, 44%). All five advanced stage cases were stage IIIC and received definitive chemoradiation. Recurrence rate was 0% (0/9) for early-stage and 60% (3/5) for advanced-stage cases. 3-year PFS was 100% for early-stage and 40% for advanced-stage. 3-year OS was 100% for early-stage and 60% for advanced-stage GCCC. CONCLUSIONS: GCCC presents at earlier ages than other cervical cancer histologic types. Although NCDB showed worse OS, our more contemporary institutional review, which incorporates updated staging and newer treatment modalities found outcomes more similar to historical references of more common histologic subtypes.

Intraluminal tumor cells and prognostic accuracy of endometrial cancer stage criteria: A multi-institution study.

OBJECTIVE: Endometrial cancer stage is a strong prognostic factor; however, the current stage classification does not incorporate transtubal spread as determined by intraluminal tumor cells (ILTCs). We examined relationships between ILTCs and survival outcomes according to histological subtype and stage and examined whether identification of ILTCs improves prognostic accuracy of endometrial cancer staging. METHODS: We conducted a retrospective cohort study of women diagnosed with endometrial cancer at five academic hospitals between 2007 and 2012. Pathologists determined ILTC presence (no vs. yes) and location (free in lumen vs. attached to epithelial surface) based on pathology review of hematoxylin and eosin-stained sections of fallopian tubes. Associations between ILTCs with time to recurrence (TTR) and overall survival (OS) were examined with Cox proportional hazards models adjusted for other prognostic factors. Model discrimination metrics were used to assess the addition of ILTCs to stage for prediction of 5-year TTR and OS. RESULTS: In the overall study population (N = 1303), ILTCs were not independently associated with TTR (HR = 0.95, 95% CI = 0.69-1.32) or OS (HR = 0.97, 95% CI = 0.72-1.31). Among 805 women with stage I disease, ILTCs were independently associated with worse TTR (HR = 2.31, 95% CI = 1.06-5.05) and OS (HR = 2.16, 95% CI = 1.14-4.11). Upstaging early-stage cases with ILTCs present did not increase model discrimination. CONCLUSION: While our data do not suggest that endometrial cancer staging guidelines should be revised to include ILTCs, associations between ILTCs and reduced survival observed among stage I cases suggest this tumor feature holds clinical relevance for subgroups of endometrial cancer patients.

Noncatalytic PTEN missense mutation predisposes to organ-selective cancer development in vivo.

Inactivation of phosphatase and tensin homology deleted on chromosome 10 (PTEN) is linked to increased PI3K-AKT signaling, enhanced organismal growth, and cancer development. Here we generated and analyzed Pten knock-in mice harboring a C2 domain missense mutation at phenylalanine 341 (Pten(FV)), found in human cancer. Despite having reduced levels of PTEN protein, homozygous Pten(FV/FV) embryos have intact AKT signaling, develop normally, and are carried to term. Heterozygous Pten(FV/+) mice develop carcinoma in the thymus, stomach, adrenal medulla, and mammary gland but not in other organs typically sensitive to Pten deficiency, including the thyroid, prostate, and uterus. Progression to carcinoma in sensitive organs ensues in the absence of overt AKT activation. Carcinoma in the uterus, a cancer-resistant organ, requires a second clonal event associated with the spontaneous activation of AKT and downstream signaling. In summary, this PTEN noncatalytic missense mutation exposes a core tumor suppressor function distinct from inhibition of canonical AKT signaling that predisposes to organ-selective cancer development in vivo.

Determinants of Surgical Approach and Survival Among Women with Endometrial Carcinoma.

STUDY OBJECTIVE: To investigate determinants of surgical approach among women with endometrial carcinoma (EC) and associations between surgical approach and overall survival (OS). DESIGN: Retrospective cohort. SETTING: The National Cancer Database, 2010 to 2015. PATIENTS: A total of 140 470 patients with histologically confirmed EC who underwent hysterectomy. INTERVENTIONS: Patients were grouped according to surgical approach. MEASUREMENTS AND MAIN RESULTS: A total of 140 470 patients with EC were included. Robotic-assisted laparoscopy (RAL) was the most common surgical approach (48.8%), followed by laparotomy (33.6%) and traditional laparoscopy (17.6%). Use of RAL increased over the study period, and the percentages of cases managed by laparotomy decreased. Older women, those with insurance, residing in ZIP codes with lower proportions of individuals who did not graduate from high school, and those treated at noncommunity cancer programs were less likely to undergo laparotomy than RAL, and non-white women, those diagnosed with high-grade histology, and those with advanced-stage EC were more likely to undergo laparotomy than RAL. Compared with RAL, all other surgical approaches were associated with worse OS (laparotomy: hazard ratio 1.21; 95% confidence interval, 1.18-1.25; traditional laparoscopy: hazard ratio 1.06; 95% confidence interval, 1.02-1.09). Significant effect modification of the surgical approach and OS relationship according to age, race, histology, stage, and adjuvant treatment was observed. CONCLUSION: RAL increased in frequency over the study period and was associated with improved OS, supporting the continued use of RAL for EC management.

Ovarian insufficiency and CTNNB1 mutations drive malignant transformation of endometrial hyperplasia with altered PTEN/PI3K activities.

Endometrioid endometrial carcinomas (EECs) carry multiple driver mutations even when they are low grade. However, the biological significance of these concurrent mutations is unknown. We explored the interactions among three signature EEC mutations: loss-of-function (LOF) mutations in PTEN, gain-of-function (GOF) mutations of phosphoinositide 3-kinase (PI3K), and CTNNB1 exon 3 mutations, utilizing in vivo mutagenesis of the mouse uterine epithelium. While epithelial cells with a monoallelic mutation in any one of three genes failed to propagate in the endometrium, any combination of two or more mutant alleles promoted the growth of epithelium, causing simple hyperplasia, in a dose-dependent manner. Notably, Ctnnb1 exon 3 deletion significantly increased the size of hyperplastic lesions by promoting the growth of PTEN LOF and/or PI3K GOF mutant cells through the activation of neoadenogenesis pathways. Although these three mutations were insufficient to cause EEC in intact female mice, castration triggered malignant transformation, leading to myometrial invasion and serosal metastasis. Treatment of castrated mice with progesterone or estradiol attenuated the neoplastic transformation. This study demonstrates that multiple driver mutations are required for premalignant cells to break the growth-repressing field effect of normal endometrium maintained by ovarian steroids and that CTNNB1 exon 3 mutations play critical roles in the growth of preneoplastic cells within the endometrium of premenopausal women and in the myometrial invasion of EECs in menopausal women.

Endometrial Cancer: Who Lives, Who Dies, Can We Improve Their Story?

BACKGROUND: Endometrial cancer (EC) is the most common gynecologic cancer in the U.S. The objective of this cohort study was to characterize the clinical and pathologic features that are associated with endometrial cancer-specific death for women cared for at a single National Cancer Institute-designated comprehensive cancer center. PATIENTS, MATERIALS, AND METHODS: This is a retrospective cohort from 2014 to 2017 including all women who had a hysterectomy for EC. Charts were reviewed for clinical and pathologic data, focusing on survival outcomes. RESULTS: Seven hundred seventy-one patients with EC underwent hysterectomy with 760 informative for outcomes. Seventy-six (10%) deaths were related to their EC; 62 women died from recurrent EC. Nonendometrioid histology and advanced stage were predictors of recurrence and EC death. Among patients with endometrioid ECs, mismatch repair status was significantly associated with EC-specific survival (relative risk = 4.8; 95% confidence interval, 2.3-10.3; p < .0001). Most patients with EC who recurred died of their disease 62/83 (74.7%). Nearly half of the patients that recurred (27/62) had no additional therapy at the time of recurrence. Overall survival was significantly longer for those women who had additional treatment at the time of recurrence; however, the improvement in overall survival with therapy at recurrence was largely attributable to effects in those women who were adjuvant therapy naïve. CONCLUSION: Although there is benefit of treatment at the time of recurrence for treatment-naïve women; only approximately half of patients were able to receive therapy. There is an urgent need for continued efforts for more effective EC therapy in both the front-line and recurrent setting as well as early identification of cancer diagnosis and recurrence. IMPLICATIONS FOR PRACTICE: Approximately 10% of patients died of their endometrial cancer. Most deaths were from recurrent disease; however, almost 20% of endometrial cancer deaths were within 120 days of surgery. Although treatment at the time of recurrence improves overall survival, only approximately half of patients will receive therapy at the time of recurrence. Traditional prognostic features like histology and stage remain important to predict risk of recurrence, and newer biomarkers, such as mismatch repair status, may improve risk stratification and targeted therapy. There remains an urgent need for improved therapy and early detection of diagnosis and recurrence.

Double somatic mismatch repair gene pathogenic variants as common as Lynch syndrome among endometrial cancer patients.

OBJECTIVE: Lynch syndrome is the most common cause of inherited endometrial cancer, attributable to germline pathogenic variants (PV) in mismatch repair (MMR) genes. Tumor microsatellite instability (MSI-high) and MMR IHC abnormalities are characteristics of Lynch syndrome. Double somatic MMR gene PV also cause MSI-high endometrial cancers. The aim of this study was to determine the relative frequency of Lynch syndrome and double somatic MMR PV. METHODS: 341 endometrial cancer patients enrolled in the Ohio Colorectal Cancer Prevention Initiative at The Ohio State University Comprehensive Cancer Center from 1/1/13-12/31/16. All tumors underwent immunohistochemical (IHC) staining for the four MMR proteins, MSI testing, and MLH1 methylation testing if the tumor was MMR-deficient (dMMR). Germline genetic testing for Lynch syndrome was undertaken for all cases with dMMR tumors lacking MLH1 methylation. Tumor sequencing followed if a germline MMR gene PV was not identified. RESULTS: Twenty-seven percent (91/341) of tumors were either MSI-high or had abnormal IHC indicating dMMR. As expected, most dMMR tumors had MLH1 methylation; (69, 75.8% of the dMMR cases; 20.2% of total). Among the 22 (6.5%) cases with dMMR not explained by methylation, 10 (2.9% of total) were found to have Lynch syndrome (6 MSH6, 3 MSH2, 1 PMS2). Double somatic MMR PV accounted for the remaining 12 dMMR cases (3.5% of total). CONCLUSIONS: Since double somatic MMR gene PV are as common as Lynch syndrome among endometrial cancer patients, paired tumor and germline testing for patients with non-methylated dMMR tumor may be the most efficient approach for LS screening.

Prospective clinical trial of robotic sentinel lymph node assessment with isosulfane blue (ISB) and indocyanine green (ICG) in endometrial cancer and the impact of ultrastaging (NCT01818739).

OBJECTIVES: To assess the performance sentinel lymph node (SLN) biopsy and effect of ultrastaging in clinically early stage endometrial cancer. METHODS: Patients with endometrial cancer prospectively enrolled after informed consent was obtained. The cervix was injected superficially with 1 mL of ISB and 1 mL of ICG (diluted 1:25) at 3 and 9 o'clock each. SLN biopsy was followed by complete pelvic lymphadenectomy (aortic lymphadenectomy at the discretion of the surgeon). Lymph nodes (LNs) were analyzed by standard sectioning with H&E; ultrastaging of SLN was done retrospectively and blinded to treating physicians. RESULTS: 204 patients received dye injections. In 184 (90.2%) patients at least one SLN was identified. Of all patients, 138 (68%) had bilateral mapping. In the patients with successful mapping of a hemipelvis, ICG detected SLNs in 83% and ISB in 64% of cases (p < 0.0001). Median BMI (kg/m2) for patients with successful mapping was 35.7 compared to 40.1 for those who did not map (p = 0.01). Twenty-three (11.3%) patients had positive LNs. Applying the SLN algorithm, positive nodes were detected in 21/23 (91.3%). The negative predictive value (NPV) was 98.9% (95% CI: 96.01% to 99.71%). Eleven patients had positive SLN with isolated tumor cells (ITCs) or micrometastases detected on ultrastaging. Including these patients, 34 (17%) had positive LNs, increasing the NPV to 99% and sensitivity to 94%. There were no recurrences in patients with ITCs only. CONCLUSIONS: SLN assessment in endometrial cancer is feasible and safe with high NPV (99%). ICG was more effective in detecting SLN compared to ISB. Although ultrastaging detected additional positive LNs, treatment based on standard sectioning appears reasonable but further research is needed.

Radiation-associated Angiosarcoma Mimicking Fallopian Tube High-grade Serous Carcinoma in a Woman With De Novo Li-Fraumeni Syndrome.

We present a case study of a woman with history of rectal adenocarcinoma, and a new diagnosis of radiation-associated angiosarcoma mimicking fallopian tube high-grade serous carcinoma who was subsequently found to have de novo Li-Fraumeni syndrome. Our objective is to highlight angiosarcoma as a potential pitfall in the diagnosis of high-grade serous carcinoma.

Clinicopathologic characteristics, tumor infiltrating lymphocytes and programed cell death ligand-1 expression in 162 endometrial carcinomas with deficient mismatch repair function.

OBJECTIVE: Endometrial carcinoma (EC) with deficient mismatch repair (dMMR) protein has been reported to have increased tumor infiltrating lymphocytes (TILs) and programed cell death ligand-1 (PD-L1) expression. TILs and PD-L1 expression are compared between two main types of dMMR ECs (epigenetic dMMR due to MLH1 promoter methylation vs mutated dMMR due to genetic mutation). METHODS: Immunohistochemistry for PD-L1 was performed in triplicate on tissue microarray sections. TILs were semi-quantitatively evaluated on whole-slide images of whole histologic sections. The clinicopathologic characteristics together with PD-L1 expression and TILs were analyzed between mutated and epigenetic dMMR ECs. RESULTS: Of the 162 dMMR ECs identified, 126 had epigenetic dMMR and 36 had mutated dMMR. Univariate analysis demonstrated mutated dMMR ECs showed younger age, less myometrium invasion of >50%, less lymphovascular invasion, and more TILs than epigenetic dMMR ECs. Multivariate analysis demonstrated significantly younger age and more TILs in mutated dMMR ECs than in epigenetic ECs. PD-L1 expression did not show any significant difference between these two groups. Seventeen (13.5%) patients with epigenetic dMMR EC had recurrence and 13 (10.3%) patients died of disease. In contrast, only one patient with mutated dMMR EC had recurrence (3%) and died of disease (3%). CONCLUSION: ECs with mutated dMMR demonstrated significantly increased TILs than ECs with epigenetic dMMR, suggesting a stronger immune reaction and potential response to immunotherapy in these tumors.

Intentional weight loss, weight cycling, and endometrial cancer risk: a systematic review and meta-analysis.

PURPOSE: Weight cycling, defined as intentional weight loss followed by unintentional weight regain, may attenuate the benefit of intentional weight loss on endometrial cancer risk. We summarized the literature on intentional weight loss, weight cycling after intentional weight loss, bariatric surgery, and endometrial cancer risk. METHODS: A systematic search was conducted using MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases published between January 2000 and November 2018. We followed Preferred Reporting Items of Systematic Reviews and Meta-analysis (PRISMA) guidelines. We qualitatively summarized studies related to intentional weight loss and weight cycling due to the inconsistent definition, and quantitatively summarized studies when bariatric surgery was the mechanism of intentional weight loss. RESULTS: A total of 127 full-text articles were reviewed, and 13 were included (bariatric surgery n=7, self-reported intentional weight loss n=2, self-reported weight cycling n=4). Qualitative synthesis suggested that, compared with stable weight, self-reported intentional weight loss was associated with lower endometrial cancer risk (RR range 0.61-0.96), whereas self-reported weight cycling was associated with higher endometrial cancer risk (OR range 1.07-2.33). The meta-analysis yielded a 59% lower risk of endometrial cancer following bariatric surgery (OR 0.41, 95% CI 0.22 to 0.74). CONCLUSIONS: Our findings support the notion that intentional weight loss and maintenance of a stable, healthy weight can lower endometrial cancer risk. Strategies to improve awareness and maintenance of weight loss among women with obesity are needed to reduce endometrial cancer risk.

Detection of endometrial cancer cells in the fallopian tube lumen is associated with adverse prognostic factors and reduced survival.

OBJECTIVE: Stage is a critical determinant of prognosis and treatment for endometrial cancer (EC) patients. Women who have had a tubal ligation for sterilization have improved EC survival, secondary to lower stage at presentation, suggesting that transtubal spread may represent an important route of metastasis. We evaluated detection of intraluminal tumor cells (ILTCs) in relation to tumor characteristics and survival. METHODS: One pathologist retrospectively evaluated hematoxylin and eosin sections of routinely collected fallopian tubes for ILTCs from 295 EC patients, masked to outcome. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between demographic (age, race) and clinical [FIGO 2009 stage, lymphovascular space invasion (LVSI), histological subtype] characteristics and ILTCs. Cox regression was used to estimate hazard ratios (HRs) and 95% CIs for associations between ILTCs and recurrence-free survival (RFS) and EC-specific survival, overall and stratified by histological subtype or stage. RESULTS: In univariable logistic regression models, age (55-64 vs. ≥65: OR = 3.41, 95% CI = 1.48-7.84), stage (stage IV vs. stage I OR = 14.58, 95% CI = 5.27-40.35), LVSI (OR = 2.93, 95% CI = 1.42-6.04), and histological subtype (serous vs. low-grade endometrioid OR = 3.21, 95% CI = 1.08-9.58), were associated with ILTCs. Only age and stage remained significantly associated with ILTCs in adjusted models. ILTCs were significantly associated with lower EC-specific survival among women with serous EC or stage I disease; however, adjustment for age, stage, and histology attenuated these associations. CONCLUSION: Our findings suggest that ILTCs are associated with adverse EC prognostic features and reduced survival in cases of early stage or serous histology.

An NRG Oncology/GOG study of molecular classification for risk prediction in endometrioid endometrial cancer.

OBJECTIVES: The purpose of this study was to assess the prognostic significance of a simplified, clinically accessible classification system for endometrioid endometrial cancers combining Lynch syndrome screening and molecular risk stratification. METHODS: Tumors from NRG/GOG GOG210 were evaluated for mismatch repair defects (MSI, MMR IHC, and MLH1 methylation), POLE mutations, and loss of heterozygosity. TP53 was evaluated in a subset of cases. Tumors were assigned to four molecular classes. Relationships between molecular classes and clinicopathologic variables were assessed using contingency tests and Cox proportional methods. RESULTS: Molecular classification was successful for 982 tumors. Based on the NCI consensus MSI panel assessing MSI and loss of heterozygosity combined with POLE testing, 49% of tumors were classified copy number stable (CNS), 39% MMR deficient, 8% copy number altered (CNA) and 4% POLE mutant. Cancer-specific mortality occurred in 5% of patients with CNS tumors; 2.6% with POLE tumors; 7.6% with MMR deficient tumors and 19% with CNA tumors. The CNA group had worse progression-free (HR 2.31, 95%CI 1.53-3.49) and cancer-specific survival (HR 3.95; 95%CI 2.10-7.44). The POLE group had improved outcomes, but the differences were not statistically significant. CNA class remained significant for cancer-specific survival (HR 2.11; 95%CI 1.04-4.26) in multivariable analysis. The CNA molecular class was associated with TP53 mutation and expression status. CONCLUSIONS: A simple molecular classification for endometrioid endometrial cancers that can be easily combined with Lynch syndrome screening provides important prognostic information. These findings support prospective clinical validation and further studies on the predictive value of a simplified molecular classification system.

Programmed Death Ligand 1 Expression Among 700 Consecutive Endometrial Cancers: Strong Association With Mismatch Repair Protein Deficiency.

OBJECTIVE: This study aims to determine the prevalence of programmed death ligand 1 (PD-L1) expression in endometrial carcinoma (EC) and determine clinical and pathological associations. METHODS: Immunohistochemistry for PD-L1 was performed on sections of a triple-core tissue microarray of 700 ECs. Positive PD-L1 expression, defined as 1% of cells staining positive, was evaluated in tumor and stromal compartments. Using age-adjusted logistic regression, we estimated odds ratios and 95% confidence intervals for associations between PD-L1 expression (overall and by staining compartment) with clinical and tumor characteristics. Kaplan-Meier plots and log-rank tests were used to evaluate associations between PD-L1 expression and EC-specific survival. RESULTS: PD-L1 expression was observed in 100 cases (14.3%), including 27 (3.9%) with expression in tumor cells only, 35 (5.0%) with expression in both tumor cells and stroma, and 38 (5.4%) with expression in stroma only. Expression was observed in ECs of different histologic types. Tumors characterized by loss of mismatch repair proteins were significantly associated with tumoral PD-L1 expression (P < 0.0001), but not with stromal PD-L1 expression. Both tumoral and stromal PD-L1 expressions were associated with high-grade endometrioid histology, nonendometrioid histology, and lymphovascular space invasion. We observed no significant associations between PD-L1 expression and EC-specific survival. CONCLUSIONS: PD-L1 is expressed in a significant proportion of EC and is associated with mismatch repair deficiency, potentially representing a mechanism of tumor immune evasion and a therapeutic target in EC.

Bokhman Redux: Endometrial cancer "types" in the 21st century.

In 1983 Jan V. Bokhman, M.D. published a landmark paper entitled "Two Pathogenetic Types of Endometrial Carcinoma" in which an enduring dualistic view of endometrial cancer was first proposed. "Type I" cancers are thought to represent estrogen driven mostly low grade endometrioid tumors strongly associated with obesity and other components of the metabolic syndrome. "Type II" cancers represent higher grade non-endometrioid tumors for which the latter associations are less significant. Basic tenets of this dichotomy including significant prognostic differences have been abundantly confirmed by later literature. The construct has in turn contributed a useful framework for decades of teaching and scientific advancement across disciplines. However, recent large epidemiologic studies indicate a more complex web of risk factors with obesity and hormones likely playing an important role across the entire endometrial cancer histologic and clinical spectrum. Moreover, high quality molecular data and refinements in pathologic classification challenge any simplistic classification of endometrial cancer. For example, the Cancer Genome Atlas (TCGA) recently defined four clinically distinct endometrial cancer types based on their overall mutational burden, specific p53, POLE and PTEN mutations, microsatellite instability and histology. Additionally, new histologic categories with clear prognostic implications have been accepted and it is becoming evident from an epidemiologic point of view that metabolic factors may play an important role in endometrial cancer overall. While Bokhman's intuitive dualistic model remains relevant when working with large registries and databases lacking granular information; most other efforts should integrate clinical, pathological and molecular specifics into more nuanced classifications.

Recurrent low grade serous ovarian cancer in a 20 year old woman: A case from the Ohio State University College of Medicine.

A 20 year old with recurrent low-grade serous carcinoma (LGSC) is discussed. The differential diagnosis, pathology, epidemiology, treatment options are discussed. Focus on the molecular pathways of LGSC and the implications of the diagnosis on fertility are highlighted.

Epigenetic silencing of MLH1 in endometrial cancers is associated with larger tumor volume, increased rate of lymph node positivity and reduced recurrence-free survival.

OBJECTIVES: To determine the relationship between mismatch repair (MMR) classification and clinicopathologic features including tumor volume, and explore outcomes by MMR class in a contemporary cohort. METHODS: Single institution cohort evaluating MMR classification for endometrial cancers (EC). MMR immunohistochemistry (IHC)±microsatellite instability (MSI) testing and reflex MLH1 methylation testing was performed. Tumors with MMR abnormalities by IHC or MSI and MLH1 methylation were classified as epigenetic MMR deficiency while those without MLH1 methylation were classified as probable MMR mutations. Clinicopathologic characteristics were analyzed. RESULTS: 466 endometrial cancers were classified; 75% as MMR proficient, 20% epigenetic MMR defects, and 5% as probable MMR mutations. Epigenetic MMR defects were associated with advanced stage, higher grade, presence of lymphovascular space invasion, and older age. MMR class was significantly associated with tumor volume, an association not previously reported. The epigenetic MMR defect tumors median volume was 10,220mm3 compared to 3321mm3 and 2,846mm3, for MMR proficient and probable MMR mutations respectively (P<0.0001). Higher tumor volume was associated with lymph node involvement. Endometrioid EC cases with epigenetic MMR defects had significantly reduced recurrence-free survival (RFS). Among advanced stage (III/IV) endometrioid EC the epigenetic MMR defect group was more likely to recur compared to the MMR proficient group (47.7% vs 3.4%) despite receiving similar adjuvant therapy. In contrast, there was no difference in the number of early stage recurrences for the different MMR classes. CONCLUSIONS: MMR testing that includes MLH1 methylation analysis defines a subset of tumors that have worse prognostic features and reduced RFS.