Polymerase ε (POLE) ultra-mutation in uterine tumors correlates with T lymphocyte infiltration and increased resistance to platinum-based chemotherapy in vitro

High prevalence of "non-pathogenic" POLE mutation with poor prognosis in a cohort of endometrial cancer from South India

OBJECTIVE

The Cancer Genome Atlas (TCGA) project identified favorable prognosis regarding the ultra-mutated endometrial cancer (EC) subtype linked to polymerase epsilon gene (POLE) mutations. This study investigated POLE mutations in EC of Indian patients.

METHODS

This retrospective analytical study was conducted between January 2016 and January 2023 at the Government Medical College, Kozhikode, and the MVR Cancer Center, Kozhikode, Kerala. Sanger sequencing of POLE gene exons 9 and 13 in 151 EC patients was carried out to analyze the relationship between mutations and epidemiological factors, clinicopathologic features, and treatment outcomes.

RESULTS

Among 151 cases enrolled, 39 were unique POLE-mutated cases. Significant associations were high-grade tumors, myometrial invasion >50%, and Lymph-vascular space invasion (LVSI). The median follow-up was 40 months (95% confidence interval [CI], 34-46). A lower mean disease-specific survival (DSS) of 51.7 months (95% CI, 43.7-59.6) was noted in the POLE-mutated group compared with 72.11 months (95% CI, 67.60-76.62) for the POLE wild-type. A statistically significant hazard ratio (HR) of 2.683 for DSS in the POLE-mutated group was noted. In advanced stages (FIGO stages II-IV), a nine-fold HR for DSS and overall survival (OS) compared with POLE wild-type was identified. After controlling for treatment effects using Cox proportional HR, advanced-stage POLE-mutated tumors had a significantly higher HR of 8.67 for DSS compared with POLE-wild-type tumors of the same stage.

CONCLUSION

This study identified a unique set of POLE mutations in Indian EC patients associated with poor prognosis, which were particularly pronounced in advanced stages. Advanced stage of presentation, type of POLE mutations, and possibly ethnicity are predictors of adverse outcomes in POLE-mutated EC. The present study highlights ethnicity as a determinant of phenotypic expression of genetic change.

Morules and β-catenin predict POLE mutation status in endometrial cancer: A pathway to more cost-effective diagnostic procedures

OBJECTIVES

The characterization of DNA polymerase epsilon (POLE) mutations has transformed the classification of endometrial endometrioid carcinomas (EECs), highlighting the need for efficient identification methods. This study aims to examine the relationship between distinct morphologic features-namely, squamous morules and squamous differentiation (SD), as well as β-catenin expression-and the POLE mutation status in endometrial cancer (EC).

METHODS

Our study included 35 POLE-mutated (POLEmut) EC cases and 395 non-POLEmut EEC cases.

RESULTS

Notably, we observed no presence of morules in POLEmut cases, while SD was identified in 20% of instances. Conversely, morules and SD were identified in 12.7% and 26.1% of non-POLEmut EC cases, respectively, with morules consistently linked to a POLE wild-type status. The nuclear β-catenin expression is typically absent in tumors with wild-type POLE (wt-POLE) status.

CONCLUSIONS

Our findings suggest that the presence of either morules or nuclear β-catenin expression in EEC could practically rule out the presence of POLE mutations. These morphologic and immunohistochemical features can be used as preliminary screening tools for POLE mutations, offering significant savings in time and resources and potentially enhancing clinical decision-making and patient management strategies. However, further validation in larger, multi-institutional studies is required to fully understand the implications of these findings on clinical practice.

Molecular Classification of Endometrial Cancer and Its Impact on Therapy Selection

Endometrial cancer (EC) accounts for 90% of uterine cancer cases. It is considered not only one of the most common gynecological malignancies but also one of the most frequent cancers among women overall. Nowadays, the differentiation of EC subtypes is based on immunohistochemistry and molecular techniques. It is considered that patients' prognosis and the implementation of the appropriate treatment depend on the cancer subtype. Patients with pathogenic variants in POLE have the most favorable outcome, while those with abnormal p53 protein have the poorest. Therefore, in patients with POLE mutation, the de-escalation of postoperative treatment may be considered, and patients with abnormal p53 protein should be subjected to intensive adjuvant therapy. Patients with a DNA mismatch repair (dMMR) deficiency are classified in the intermediate prognosis group as EC patients without a specific molecular profile. Immunotherapy has been recognized as an effective treatment method in patients with advanced or recurrent EC with a mismatch deficiency. Thus, different adjuvant therapy approaches, including targeted therapy and immunotherapy, are being proposed depending on the EC subtype, and international guidelines, such as those published by ESMO and ESGO/ESTRO/ESP, include recommendations for performing the molecular classification of all EC cases. The decision about adjuvant therapy selection has to be based not only on clinical data and histological type and stage of cancer, but, following international recommendations, has to include EC molecular subtyping. This review describes how molecular classification could support more optimal therapeutic management in endometrial cancer patients.

Molecular Classification of Endometrial Endometrioid Carcinoma With Microcystic Elongated and Fragmented Pattern

The studies on the molecular classification of endometrioid carcinoma (EC) with microcystic, elongated, and fragmented (MELF) pattern invasion are limited. In this study, 77 cases of ECs with MELF patterns in Chinese women were collected. The molecular classification of the fifth edition of the World Health Organization was used to classify the molecular subtypes using immunohistochemistry staining (mismatch repair [MMR]-immunohistochemistry: MSH2, MSH6, MLH1, and PMS2; p53) and Sanger sequencing targeted POLE . The results showed that the prevalence of the 4 molecular subtypes in EC with MELF pattern was 6.5% (5/77) for POLE mutation, 20.8% (16/77) for MMR deficient, 11.7% (9/77) for p53-mutant, and 61.0% (47/77) for no specific molecular profile. The clinicopathological characteristics of each subtype were compared. The p53-mutant and no specific molecular profile subgroups were associated with higher International Federation of Gynecology and Obstetrics stage and International Federation of Gynecology and Obstetrics grade, deeper myometrial invasion, lymphovascular space invasion, lymph node metastasis, and absence of tumor-infiltrating lymphocytes, whereas the POLE mutation and MMR deficient subgroups were associated with lower aggressive features and prominent tumor-infiltrating lymphocytes. Progression-free survival showed that the p53-mutant and no specific molecular profile subgroups had a poorer prognosis than the POLE mutation and MMR deficient subgroups. However, lymph node metastasis was an independent factor associated with a higher risk of disease recurrence in multivariate analysis. In conclusion, ECs with MELF patterns can be divided into 4 molecular subtypes with discrepancies in aggressive clinicopathological characteristics and tumor-infiltrating lymphocytes. Molecular classification has clinical significance in a morpho-molecular approach for ECs with MELF patterns.

Special Considerations in Classification and Workup of Endometrial Carcinomas

CONTEXT.—

A variety of uncommon malignant endometrial tumors can be challenging to diagnose because of overlapping morphology with more common entities. In some cases, immunohistochemical stains and/or molecular testing allow for more definitive diagnosis or prognostication.

OBJECTIVE.—

To review classic morphologic features of uncommon endometrial tumors, pathologic features of these tumors and their mimics, and the evidence for use of immunohistochemistry and molecular testing in the diagnosis of these tumors.

DATA SOURCES.—

University of Michigan (Ann Arbor) cases and review of pertinent literature about each entity.

CONCLUSIONS.—

Although each of these uncommon endometrial tumors has morphologic mimics, key histologic features, immunohistochemical stains, and molecular testing allow for accurate classification.

Association of molecular subgroups with pathological parameters in endometrial carcinomas

BACKGROUND

The integration of molecular features into the already existing pathological classification of endometrial carcinomas will offer significant prognostic information. As the literature search reveals, there are no studies from India that have classified these carcinomas based on molecular subtypes. The aim of the study was to classify endometrial carcinomas into four subtypes based on their molecular and immunohistochemical features and to find out the association of each of these molecular subtypes with the other pathological parameters.

METHODS

A prospective study was done on 37 consecutive cases of fresh hysterectomy specimens, biopsy-proven as endometrial carcinomas between November 2019 and August 2020. Three immunohistochemical markers ( p53 , mismatch repair proteins, MutS homolog6 and Postmeiotic seggregation 2 respectively[ MSH6 , and PMS2] ), along with DNA (deoxyribonucleic acid) sequencing of selected regions of the POLE gene was performed in each of the 37 cases. Endometrial carcinomas were subclassified into four subtypes, and the association of each of these four subtypes with the other pathological parameters was also explored. Statistical analysis was done using the IBM Statistical Package for the Social Science (SPSS) Version 20.0 software (IBM SPSS, USA).

RESULTS

Among the 37 cases studied, eight (21.6%) cases were p53 abnormal, eight (21.6%) cases showed MMR-D (mismatch repair deficient), one case (2.7%) showed mutation of POLE , and 21 cases (56.8%) were assembled under p53 wild-type. Higher grade endometrial carcinomas showed more (80.0%) p53 abnormal ( P < 0.001). All the p53 wild-type (100%) were of Type 1 endometrial carcinoma subtype ( P = 0.001) and low-grade type (90.5%; P = 0.005).

CONCLUSION

Our study confirms that the type of carcinoma and grade correlates with p53 expression, p53 abnormal being associated with higher grade and type 2 endometrial carcinomas, whereas p53 wild-type is associated with low-grade and type 1 endometrial carcinoma. There was only one case of the POLE subtype identifiable in our study.

The Clinical and Pathological Characteristics of POLE-Mutated Endometrial Cancer: A Comprehensive Review

Endometrial cancer shows high histological and molecular heterogeneity. The POLE mutation is a significant molecular alteration in endometrial cancer, leading to the identification of a specific subtype known as POLE-mutated endometrial cancer. This subtype exhibits a high tumor mutation burden, abundant lymphocyte infiltration, and a favorable prognosis, making it a promising candidate for immune checkpoint inhibitor therapy. This paper presents a comprehensive review of the clinical and pathological characteristics, outcomes, treatment advancements, pathogenic POLE gene detection, and alternative testing methods for POLE-mutated endometrial cancer.

Race, Prevalence of POLE and POLD1 Alterations, and Survival Among Patients With Endometrial Cancer

Importance

Black patients with endometrial cancer (EC) in the United States have higher mortality than patients of other races with EC. The prevalence of POLE and POLD1 pathogenic alterations in patients of different races with EC are not well studied.

Objective

To explore the prevalence of and outcomes associated with POLE and POLD1 alterations in differential racial groups.

Design, Setting, and Participants

This retrospective cohort study incorporated the largest available data set of patients with EC, including American Association for Cancer Research Project GENIE (Genomics Evidence Neoplasia Information Exchange; 5087 participants), Memorial Sloan Kettering-Metastatic Events and Tropisms (1315 participants), and the Cancer Genome Atlas Uterine Corpus Endometrial Carcinoma (517 participants), collected from 2015 to 2023, 2013 to 2021, and 2006 to 2012, respectively. The prevalence of and outcomes associated with POLE or POLD1 alterations in EC were evaluated across self-reported racial groups.

Exposure

Patients of different racial groups with EC and with or without POLE or POLD1 alterations.

Main Outcomes and Measures

The main outcome was overall survival. Data on demographic characteristics, POLE and POLD1 alteration status, histologic subtype, tumor mutation burden, fraction of genome altered, and microsatellite instability score were collected.

Results

A total of 6919 EC cases were studied, of whom 444 (6.4%), 694 (10.0%), and 4869 (70.4%) patients were self-described as Asian, Black, and White, respectively. Within these large data sets, Black patients with EC exhibited a lower weighted average prevalence of pathogenic POLE alterations (0.5% [3 of 590 cases]) compared with Asian (6.1% [26 of 424]) or White (4.6% [204 of 4520]) patients. By contrast, the prevalence of POLD1 pathogenic alterations was 5.0% (21 cases), 3.2% (19 cases), and 5.6% (255 cases) in Asian, Black, and White patients with EC, respectively. Patients with POLD1 alterations had better outcomes regardless of race, histology, and TP53 alteration status. For a total of 241 clinically annotated Black patients with EC, a composite biomarker panel of either POLD1 or POLE alterations identified 7.1% (17 patients) with positive outcomes (1 event at 70 months follow up) in the small sample of available patients.

Conclusions and Relevance

In this retrospective clinicopathological study of patients of different racial groups with EC, a composite biomarker panel of either POLD1 or POLE alteration could potentially guide treatment de-escalation, which is especially relevant for Black patients.

Replication DNA polymerases, genome instability and cancer therapies

It has been over a decade since the initial identification of exonuclease domain mutations in the genes encoding the catalytic subunits of replication DNA polymerases ϵ and δ (POLE and POLD1) in tumors from highly mutated endometrial and colorectal cancers. Interest in studying POLE and POLD1 has increased significantly since then. Prior to those landmark cancer genome sequencing studies, it was well documented that mutations in replication DNA polymerases that reduced their DNA synthesis accuracy, their exonuclease activity or their interactions with other factors could lead to increased mutagenesis, DNA damage and even tumorigenesis in mice. There are several recent, well-written reviews of replication DNA polymerases. The aim of this review is to gather and review in some detail recent studies of DNA polymerases ϵ and δ as they pertain to genome instability, cancer and potential therapeutic treatments. The focus here is primarily on recent informative studies on the significance of mutations in genes encoding their catalytic subunits (POLE and POLD1), mutational signatures, mutations in associated genes, model organisms, and the utility of chemotherapy and immune checkpoint inhibition in polymerase mutant tumors.

The Prognostic Characteristics and Recurrence Patterns of High Grade Endometrioid Endometrial Cancer: A Large Retrospective Analysis of a Tertiary Center

High grade endometrioid endometrial cancer (HGEEC) is a heterogeneous group of tumors with unclear prognostic features. The aim of the present study is to evaluate the independent risk factors for recurrence and mortality and to describe the recurrence patterns of HGEEC. Ninety-six consecutive cases of HGEEC treated with primary surgery in a single Tertiary Center were retrospectively reviewed. Clinicopathological and treatment details were recorded, and all patients were closely followed up. Disease-free, overall and cancer-specific survival rates were 83.8%, 77.8% and 83.6%, respectively. Cervical stromal involvement was independently related to recurrence (HR = 25.67; 95%CI 2.95-223.30; p = 0.003) and cancer-related death (HR = 15.39; 95%CI 1.29-183.43; p = 0.031) after adjusting for other pathological and treatment variables. Recurrence rate was 16%, with 60% of these cases having lung metastases and only one case with single vaginal vault recurrence. 81.81% of the recurrences presented with symptoms and not a single recurrence was diagnosed in routine follow-up clinical examination. In conclusion, the recurrence pattern may suggest that patient-initiated follow-up (PIFU) could be considered a potential alternative to clinical-based follow-up for HGEEC survivors, especially for patients without cervical involvement and after two years from treatment. Additional caution is needed in patients with cervical stromal involvement.

A novel somatic mutation in POLE exonuclease domain associated with ultra-mutational signature and MMR deficiency in endometrial cancer: a case report

BACKGROUND

Defect in proofreading exonuclease activity of polymerases epsilon and delta (Pols ε and δ) leads to mutagenesis and genomic instability and has been described in several cancer types. Somatic POLE exonuclease domain mutations (EDMs) have been reported in 7-12% endometrial cancers (ECs) and defined a subgroup of endometrial cancers with ultrahigh somatic mutation frequencies, high tumor infiltrated lymphocytes and favorable outcomes.

CASE PRESENTATION

Herein, we presented a novel somatic mutation in POLE exonuclease domain associated with ultra-mutational signature and MMR deficiency in endometrial cancer. A novel POLE EDM (p.T278K) was found by a 11-gene NGS panel. The MSS status detected by the MSI test was inconsistent with the dMMR status by IHC. The loss of MSH6 expression in the tumor could be interpreted by the two nonsense mutations (p.E1234* and p.E1322*) of the MSH6 gene which may lead to truncated proteins. The T278K mutation was pathogenic identified by a 602-gene NGS panel with 27.3% of C > A substitution, 0.6% of indels, 0.6% of C > G substitution and a high TMB of 203.8 mut/Mb.

CONCLUSIONS

We report an endometrial cancer patient harbored a novel somatic POLE T278K mutation. This mutation was a novel pathogenic POLE EDM should be considered as "POLE (ultramutated)" in clinical practice for the molecular classification of EC.

Immunologic Signatures across Molecular Subtypes and Potential Biomarkers for Sub-Stratification in Endometrial Cancer

Current molecular classification approaches for endometrial cancer (EC) often employ multiple testing platforms. Some subtypes still lack univocal prognostic significance, highlighting the need for risk sub-stratification. The tumor immune microenvironment (TIME) is associated with tumor progression and prognosis. We sought to investigate the feasibility of classifying EC via DNA sequencing and interrogate immunologic signatures and prognostic markers across and within subtypes, respectively. Formalin-fixed paraffin-embedding (FFPE) samples from 50 EC patients underwent targeted DNA and RNA sequencing, and multiplex immunofluorescence assay for TIME. DNA sequencing classified 10%, 20%, 52%, and 18% of patients into the subtype of POLE-mutant, microsatellite instability-high (MSI-H), TP53-wt, and TP53-mutant. POLE-mutant tumors expressed the highest T-effector and IFN-γ signature and the lowest innate anti-PD-1 resistance signature among subtypes. TP53-wt revealed a converse enrichment trend for these immunologic signatures. Survival analyses using the Cancer Genome Atlas Uterine Corpus Endometrial Carcinoma (TCGA-UCEC) dataset identified associations of CCR5 (hazard ratio (HR) = 0.71, p = 0.035), TNFRSF14 (HR = 0.58, p = 0.028), and IL-10 (HR = 2.5, p = 0.012) with overall survival within MSI-H, TP53-mutant, and TP53-wt subtype, respectively. A TIME comparison between the sub-stratified subgroups of our cohort revealed upregulated tumor infiltration of immune cells in the low-risk subgroups. Our study demonstrates that targeted DNA sequencing is an effective one-stop strategy to classify EC. Immunomodulatory genes may serve as prognostic markers within subtypes.

Characterization of hotspot exonuclease domain mutations in the DNA polymerase ϵ gene in endometrial cancer

Objective

This study was aimed to profile hotspot exonuclease domain mutations (EDMs) of the DNA polymerase ϵ gene (POLE) in endometrial cancer (EC) and to investigate the effects of EDMs on tumor cell behavior and catalytic activities of Polϵ.

Methods

POLE sequencing was performed in tumor tissue samples from patients with EC to identify hotspot EDMs. Bioinformatics tools were used to select the potential pathogenic EDMs. The association of EDMs with the clinical outcomes of patients was assessed. EC cells were transfected with wildtype POLE or POLE variants to examine the effects of the EDMs on EC cell behavior, including cell cycle, migration, and invasion. Co-immunoprecipitation was employed to obtain FLAG-tagged wildtype and mutant catalytic subunits of Polϵ, followed by the assessment of polymerase and exonuclease activities.

Results

In addition to previously reported P286R and V411L, R375Q and P452L were identified as novel, and deleterious POLE hotspot EDMs of EC. Patients in EDM group had significantly better clinical outcomes than the rest of the cohort. Compared with wildtype POLE, overexpression of POLE variants promoted cisplatin resistance, G0/G1 cell cycle arrest, and cell migration and invasion in EC cells. Overexpression of POLE variants significantly increased the abundance of 3’-OH and upregulated the expression of DNA mismatch repair genes in HEK293T cells. Compared with wildtype Polϵ, Pol ϵ mutants exhibited undermined polymerase and exonuclease abilities in the presence of mismatched nucleotides in HEK293 cells.

Conclusion

We characterized the of hotspot exonuclease domain mutations in the DNA polymerase ϵ gene and identified P286R, V411L, R375Q, and P452L as pathogenic POLE hotspot EDMs in endometrial cancer. These hotspot EDMs are associated with the malignant behavior of endometrial cancer cells in vitro and favorable prognosis in patients, suggesting that POLE affects a wide range of cellular processes beyond DNA replication and proofreading.

Immunohistochemical Markers and TILs Evaluation for Endometrial Carcinoma

Objective: The molecular classification for endometrial cancer (EC) introduced by The Cancer Genome Atlas Research Network (TCGA) and the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) proved the existence of four molecular prognostic subtypes; however, both classifications require costly technology. We suggest a prognostic model for EC based on immunohistochemistry (IHC) and tumor-infiltrating lymphocytes (TILs). Study design: One hundred patients were included. We retrospectively investigated IHC prognostic parameters: mismatch repair (MMR)-deficient tumors, p53 mutation status, progesterone receptors (PgRs), and estrogen receptors (ERs). We further evaluated TILs. These parameters were related to the clinical and morphological features and to the outcome. Results: We classified tumors into three groups (IHC analysis): MMR-deficient, p53-mutated, p53 wild-type. MMR-deficient tumors had a good prognosis, p53 wild-type tumors an intermediate one, and p53-mutated tumors had the poorest outcomes. Disease-free (DFS) and overall survival (OS) were significantly better among PgR+ tumors (respectively p = 0.011 and p = 0.001) and PgR expression is an independent prognostic factor for a better DFS frommultivariate analysis (OR = 0.3; CI: 0.1–0.9; p = 0.03).No significant correlation was observed between DFS and TILs. However, among MMR-deficient tumors, the mean value of TILs was higher than among the other tumors(111 versus 71, p = 0.01) Conclusions: The prognostic model based on IHC markers could potentially be a valid and applicable alternative to the TCGA one. The PgR determination could represent an additional prognostic factor for EC.

The prognosis of endometrial cancers stratified with conventional risk factors and modified molecular classification

This study aimed to validate the Proactive Molecular Risk Classifier for Endometrial Cancer, a modified version of The Cancer Genome Atlas, using data from 184 patients with endometrial cancer (median age: 57.5 years; median follow‐up period: 109 months) who had undergone radical surgery (including systemic lymphadenectomy) and subsequent adjuvant chemotherapy (patients with intermediate or high recurrence risk) from 2003 to 2015. Tissue microarrays were prepared from surgical specimens and classified using the conventional clinical risk classifier. Immunohistochemistry was used to detect mismatch repair proteins, L1 cell adhesion molecule, and p53. Direct sequencing was used to identify hotspot mutations in the polymerase‐epsilon gene. Forty‐five patients were identified as having high L1 cell adhesion molecule expression, 41 as low risk, 34 as mismatch repair‐deficient, 13 as polymerase‐epsilon gene‐mutated, five as having abnormal p53, and 46 as other. Patients were stratified into significantly different prognostic groups (p < 0.0001): favorable (low risk and polymerase‐epsilon gene‐mutated), intermediate (mismatch repair‐deficient and other), and unfavorable (high L1 cell adhesion molecule expression and abnormal p53) with 5‐year disease‐specific survival rates of 100%, 93.8%, and 75.1%, respectively (Kaplan–Meier method). The combination of conventional recurrent risk classification, sequencing for polymerase‐epsilon gene mutations and immunohistochemistry for L1 cell adhesion molecule, p53, and mismatch repair proteins can be used to determine the prognoses of patients with endometrial cancer.

Immune checkpoint inhibitors for recurrent endometrial cancer

INTRODUCTION

Endometrial cancer (EC) is the most common gynecologic malignancy. Outcomes for patients with advanced and/or recurrent disease have been modest with the use of chemotherapy. The approval of immune checkpoint inhibitors targeting PD-1 have recently revolutionized human cancer treatment. Recent trials with immune checkpoint inhibitors used alone or in combination with other agents, have demonstrated remarkable efficacy in the treatment of the all-comers EC patient population.

AREAS COVERED

In this article, we review major clinical trials on PD-1/PD-L1 inhibitors in advanced and recurrent EC and discuss the response rates to these agents in the context of their genomic background.

EXPERT OPINION

Immune checkpoint inhibitors have significantly changed our approach to the treatment of advanced/recurrent EC. Single agent anti-PD-1 regimens are highly effective in MMRd/MSI-H patients, but their clinical efficacy remains modest in MMR proficient/TMB low EC patients. Combination regimens that can decrease the tumor microenvironments immunosuppression and increase tumor immunogenicity represent a viable treatment option to broaden the activity of immune checkpoint inhibitors in advanced/recurrent EC patients. An increased understanding of the biomarkers of response and the molecular mechanisms of resistance to immune checkpoint inhibitors remains key for the next advancement of the field.

The clinicopathology and survival characteristics of patients with POLE proofreading mutations in endometrial carcinoma: A systematic review and meta-analysis

Background

Endometrial carcinoma (EC) is classified into four distinct molecular subgroups. Patients with polymerase epsilon exonuclease domain mutated (POLE-EDM) tumors have the best prognosis of all. This meta-analysis consolidated the clinicopathology variations reported in the POLE-mutant subtype and survival parameters in patients with EC.

Methods

The following internet data bases were searched: PubMed, Web of science, Embase and Scimage directory. Data was extracted from eligible studies including sample size, number of positive POLE-mutant cases, EDM sequencing information, clinicopathologic, and survival data. Meta-analysis and a random-effects model produced pooled estimates of POLE prognostic parameters using 95% confidence intervals (CI), hazard ratios (HR), and odds ratios (OR).

Results

The meta-analysis included 11 cohort studies comprising 5508 EC patients (442 POLE EDM tumors). Patients with POLE mutant EC were associated with improved disease specific survival (HR = 0.408, 95% CI: 0.306 to 0.543) and progression-free survival (HR = 0.231, 95% CI: 0.117 to 0.456). POLE-mutated tumors were mostly endometrioid histology (84.480%; 95% CI: 77.237 to 90.548), although not significantly more than wild type tumors (OR = 1.386; p = 0.073). The POLE mutant tumors significantly present (p<0.001) at Federation of International of Gynecologists and Obstetricians (FIGO) lower stages I-II (OR = 2.955, p<0.001) and highest grade III (OR = 1.717, P = 0.003). The tumors are significantly associated with invasion less than half (<50%) of the myometrium (OR = 1.765, p = 0.001), but not deeply invasive EC (MI>50%, OR = 0.83, p = 0.34). POLE mutations significantly protected against lymph node metastases (OR = 0.202, p = 0.001), and have no clear association with lymph-vascular space invasion (OR = 0.967, 95% 0.713–1.310, p = 0.826). The tumors are predominantly of low ESMO risk stratification distribution (40.356%; 95% CI: 27.577 to 53.838).

Conclusions

POLE mutations serve as an important biomarker of favorable prognosis in EC. The tumors are characteristically high grade, early stage, and remain localized in the endometrium with reduced likelihood of lymph node metastasis for improved survival prospects and the lowest risk classification. These findings have implications for medical management of EC.

Combination of Proactive Molecular Risk Classifier for Endometrial cancer (ProMisE) with sonographic and demographic characteristics in preoperative prediction of recurrence or progression of endometrial cancer

OBJECTIVE

To evaluate the ability of demographic and sonographic variables and the Proactive Molecular Risk Classifier for Endometrial cancer (ProMisE) classification to predict preoperatively tumor recurrence or progression in women with endometrial cancer.

METHODS

The study included 339 women with histologically confirmed endometrial cancer who underwent expert transvaginal ultrasound in a single center before surgery as part of the prospective International Endometrial Tumor Analysis 4 study or who were evaluated using the same protocol. The tumors were classified according to histotype, FIGO (International Federation of Gynecology and Obstetrics) grade and FIGO stage. In addition, molecular analysis was performed for classification into the four ProMisE subtypes: polymerase-ϵ exonuclease domain mutations (POLE EDM), mismatch repair proteins deficiency (MMR-D), protein 53 wild type (p53 wt) and protein 53 abnormal (p53 abn). Demographic and preoperative sonographic characteristics, tumor recurrence or progression and survival were compared between the ProMisE subgroups. Cox regression analysis was used to identify prognostic factors associated with recurrence or progression, using univariable models to study crude associations and multivariable models to study adjusted associations. Logistic regression and receiver-operating-characteristics (ROC)-curve analysis were used to assess the predictive ability of the preoperative prognostic factors regarding recurrence or progression of cancer within 3 years after surgery, and to compare their predictive ability to that of the European Society for Medical Oncology (ESMO) preoperative (based on depth of myometrial invasion, histotype and grade) and postoperative (based on histotype, grade, surgical stage and lymphovascular space invasion) risk classifications. In a separate subanalysis, cases were stratified according to ProMisE p53 abn status (present vs absent) and sonographic tumor size (anteroposterior (AP) diameter < 2 cm vs ≥ 2 cm).

RESULTS

Median follow-up time from surgery was 58 months (interquartile range, 48-71 months; range, 0-102 months). Recurrence or progression of cancer occurred in 51/339 (15%) women, comprising 14% of those with MMR-D, 8% of those with POLE EDM, 9% of those with p53 wt and 45% of those with p53 abn ProMisE subtype. On multivariable analysis, age, waist circumference, ProMisE subtype and tumor extension and AP diameter on ultrasound were associated with tumor recurrence or progression. A multivariable model comprising ProMisE subtype, age, waist circumference and sonographic tumor extension and size (area under the ROC curve (AUC), 0.89 (95% CI, 0.85-0.93)) had comparable ability to predict tumor recurrence/progression to that of a multivariable model comprising histotype, grade, age, waist circumference and sonographic tumor extension and size (AUC, 0.88 (95% CI, 0.83-0.92)), and better predictive ability than both the preoperative (AUC, 0.74 (95% CI, 0.67-0.82); P < 0.01) and postoperative (AUC, 0.79 (95% CI, 0.72-0.86); P < 0.01) ESMO risk classifications. Women with a combination of non-p53 abn subtype and tumor size < 2 cm (164/339 (48%)) had a very low risk (1.8%) of tumor recurrence or progression.

CONCLUSIONS

The combination of demographic characteristics, sonographic findings and ProMisE subtype had better preoperative predictive ability for tumor recurrence or progression than did the ESMO classification, supporting their use in the preoperative risk stratification of women with endometrial cancer. The combination of p53 status with ultrasound tumor size has the potential to identify preoperatively a large group of women with a very low risk of recurrence or progression. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. - Legal Statement: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The role of molecular tests for adjuvant and post-surgical treatment in gynaecological cancers

The adjuvant and post-surgical treatment of gynaecological cancers has historically been guided by the estimation of relapse risk based on clinicopathological factors determined at the time of cancer diagnosis. The recent advancement of genomic and molecular characterisation of gynaecological cancers has begun to shift paradigms in the selection of adjuvant treatment strategy. Recent data regarding the predictive and/or prognostic value of molecular tests in the treatment of advanced ovarian cancer as well as early stage endometrial cancer have been the first such examples to enter adjuvant treatment guidelines for these diseases. In this article, we discuss the current state and future development of molecular assays for gynaecological cancers and how they impact upon treatment selection for ovarian, endometrial and cervical cancers in the post-surgical setting.

Evaluation of treatment effects in patients with endometrial cancer and POLE mutations: An individual patient data meta-analysis

BACKGROUND

Endometrial cancers (ECs) with somatic mutations in DNA polymerase epsilon (POLE) are characterized by unfavorable pathological features, which prompt adjuvant treatment. Paradoxically, women with POLE-mutated EC have outstanding clinical outcomes, and this raises concerns of overtreatment. The authors investigated whether favorable outcomes were independent of treatment.

METHODS

A PubMed search for POLE and endometrial was restricted to articles published between March 1, 2012, and March 1, 2018, that provided individual patient data (IPD), adjuvant treatment, and survival. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) reporting guidelines for IPD, the authors used univariate and multivariate one-stage meta-analyses with mixed effects Cox models (random effects for study cohorts) to infer the associations of treatment, traditional prognostic factors, and outcome, which was defined as the time from first diagnosis to any adverse event (progression/recurrence or death from EC).

RESULTS

Three hundred fifty-nine women with POLE-mutated EC were identified; 294 (82%) had pathogenic mutations. Worse outcomes were demonstrated in patients with nonpathogenic POLE mutations (hazard ratio, 3.42; 95% confidence interval, 1.47-7.58; log-rank P < .01). Except for stage (P < .01), traditional prognosticators were not associated with progression/recurrence or death from disease. Adverse events were rare (11 progressions/recurrences and 3 disease-specific deaths). Salvage rates in patients who experienced recurrence were high and sustained, with 8 of 11 alive without evidence of disease (range, 5.5-14.2 years). Adjuvant treatment was not associated with outcome.

CONCLUSIONS

Clinical outcomes for ECs with pathogenic POLE mutations are not associated with most traditional risk parameters, and patients do not appear to benefit from adjuvant therapy. The observed low rates of recurrence/progression and the high and sustained salvage rates raise the possibility of safely de-escalating treatment for these patients.

LAY SUMMARY

Ten percent of all endometrial cancers have mutations in the DNA repair gene DNA polymerase epsilon (POLE). Women who have endometrial cancers with true POLE mutations experience almost no recurrences or deaths from their cancer even when their tumors appear to have very unfavorable characteristics. Additional therapy (radiation and chemotherapy) does not appear to improve outcomes for women with POLE-mutated endometrial cancer, and this supports the move to less therapy and less associated toxicity. Diligent classification of endometrial cancers by molecular features provides valuable information to inform prognosis and to direct treatment/no treatment.

Comprehensive immunomolecular profiling of endometrial carcinoma: A tertiary retrospective study

OBJECTIVE

Combined immunohistochemical and molecular classification using the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) independently predicts prognosis in endometrial carcinoma (EC). As next-generation sequencing (NGS) is entering clinical practice, we evaluated whether more comprehensive immunomolecular profiling (CIMP), including NGS and extended immunohistochemical analysis, could further refine the current ProMisE classification.

METHODS

A series of 120 consecutive ECs, classified according to ProMisE, was stained immunohistochemically for CD3, CD8, PD-L1, beta-catenin and L1CAM. An in-house 96 gene NGS panel was performed on a subset of 44 ECs, representing the 4 ProMisE subgroups (DNA polymerase epsilon catalytic subunit exonuclease domain mutated (POLEmut), mismatch repair deficient (MMRd), p53 abnormal (p53 abn) and no specific molecular profile (NSMP) ECs). Cases harboring non-hotspot POLE variants were analyzed with Illumina TruSight Oncology 500 NGS panel (TSO500) as a surrogate for whole-exome sequencing.

RESULTS

Eight cases harbored POLE variants, half of which were hotspots. Using TSO500, non-hotspot POLE variants were classified as pathogenic (3) or variant of unknown significance (1). POLEmut and MMRd ECs typically showed higher numbers of CD3⁺/CD8⁺ tumor-infiltrating lymphocytes and higher PD-L1 expression in tumor-infiltrating immune cells. p53 abn ECs showed significantly higher L1CAM immunoreactivity and frequently harbored gene amplifications including HER2 (25%), but typically lacked ARID1A or PTEN variants. Beta-catenin-positivity and FGFR2 variants were predominantly found in NSMP ECs.

CONCLUSIONS

Our data show that CIMP adds significant value to EC characterization and may help to determine pathogenicity of non-hotspot POLE variants, encountered more frequently than expected in our series. In addition, CIMP may reveal ECs benefitting from immune checkpoint inhibition and allows upfront identification of targetable alterations, such as HER2 amplification in p53 abn ECs.

Risk Assessment in Solitary Fibrous Tumor of the Uterine Corpus: Report of a Case and Systematic Review of the Literature

Solitary fibrous tumor (SFT) is an uncommon fibroblastic tumor occurring preferentially in the pleura, with a variable clinical course. SFT can arise also in numerous extrathoracic sites and very rarely in the female genital tract, with only scarce reports of uterine SFT. We reported a new uterine SFT arising in a 45-year-old woman, and we performed a systematic review of SFT cases of the uterine corpus interrogating the electronic databases PubMed, Web of Science, and Scopus. We identified only 13 patients diagnosed with SFT of the uterine corpus, including our one. Complete clinical workout at disease presentation showed no evidence of extrauterine spread in all cases, except for 1 patient who presented with metastatic disease. Tumor recurrences/metastases occurred in a minority of the patients and were poorly related to clinicopathological risk factors and patients stratification based on different scoring systems. Since the long-term clinical behavior of uterine SFT is limited and poorly predictable, extended follow-up is recommended also for all cases arising in the uterine corpus.

Immunotherapy in endometrial cancer: rationale, practice and perspectives

Tumor immunotherapy has attracted more and more attention nowadays, and multiple clinical trials have confirmed its effect in a variety of solid tumors. Immune checkpoint inhibitors (ICIs), cancer vaccines, adoptive cell transfer (ACT), and lymphocyte-promoting cytokines are the main immunotherapy methods. Endometrial cancer (EC) is one of the most frequent tumors in women and the prognosis of recurrent or metastatic EC is poor. Since molecular classification has been applied to EC, immunotherapy for different EC subtypes (especially POLE and MSI-H) has gradually attracted attention. In this review, we focus on the expression and molecular basis of the main biomarkers in the immunotherapy of EC firstly, as well as their clinical application significance and limitations. Blocking tumor immune checkpoints is one of the most effective strategies for cancer treatment in recent years, and has now become the focus in the field of tumor research and treatment. We summarized clinical date of planned and ongoing clinical trials and introduced other common immunotherapy methods in EC, such as cancer vaccine and ACT. Hormone aberrations, metabolic syndrome (MetS) and p53 mutant and that affect the immunotherapy of endometrial cancer will also be discussed in this review.

Molecularly Classified Uterine FIGO Grade 3 Endometrioid Carcinomas Show Distinctive Clinical Outcomes But Overlapping Morphologic Features

FIGO grade 3 endometrioid endometrial carcinoma (EEC) is a heterogenous group of tumors with variable molecular and clinicopathologic characteristics but is treated clinically as a single entity. There is a need for additional objective markers to help guide management. The aim of this study was to evaluate a cohort of FIGO grade 3 EEC to validate the prognostic impact of molecular classification using POLE mutation (POLE-mut) analysis and immunohistochemistry for p53 and mismatch repair proteins. A secondary aim was to assess for any morphologic or immunophenotypic correlates among the molecular groups. Ninety-five cases of FIGO grade 3 EEC who underwent a hysterectomy at our institution were identified. Ten tumors (11%) harbored POLE-mut, 35 tumors (37%) showed mismatch repair deficiency, 18 tumors (19%) showed aberrant p53 staining (p53-ab), and 26 cases (27%) lacked all of these findings and were classified as no specific molecular profile. Six separate cases harbored >1 abnormality (multiple classifier), 5 of which had POLE-mut. The POLE-mut group and multiple classifier group showed excellent clinical outcomes, the p53-ab group showed the worst clinical outcomes and the 2 remaining groups showed intermediate prognosis. While the POLE-mut tumors showed a statistically significant enrichment for morphologic features including serous-like atypia and lymphocytic infiltrates, these findings were seen across all 4 molecular groups. There was no correlation between molecular grouping and tumor immunophenotypic findings, but overall 18% and 24% of tumors were completely negative for PAX-8 and estrogen receptor, respectively. Five CTNNB1 mutations were identified, 3 of which occurred in the context of a POLE-mut (including 1 multiple classifier case with MLH1/PMS2 loss). Thus our study corroborates the prognostic impact of molecular classification of high-grade endometrioid carcinoma of the uterus, achieved by readily available immunohistochemical stains in addition to POLE-mut analysis.

Tumor-infiltrating lymphocytes and POLE mutation in endometrial carcinoma

BACKGROUND

Polymerase-ε (POLE)-mutated endometrial carcinomas (ECs) have displayed an increased number of tumor-infiltrating lymphocytes (TIL) compared to POLE-wild-type ECs. However, it is unclear if TIL may aid in identifying POLE-mutated ECs when molecular data are unavailable. The identification of a POLE mutation surrogate may be crucial to translate TCGA/ProMisE risk assessment in the clinical practice.

AIM

To assess TIL as histological surrogate of POLE mutation in EC.

MATERIALS AND METHODS

Seven electronic databases were searched from their inception to September 2020 for studies that allowed data extraction about TIL and TCGA/ProMisE groups of EC. We calculated pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), diagnostic odds ratio (DOR) and area under the curve (AUC) on SROC curves of TIL in distinguishing POLE-mutated from i) POLE-wild-type, ii) no specific molecular profile (NSMP), iii) POLE-wild-type/MMR-proficient, iii) MMR-deficient ECs.

RESULTS

10 studies assessing 1169 women were included in the qualitative analysis. TIL-high pattern showed: sensitivity = 0.65, specificity = 0.63, LR + =2.06, LR- = 0.48, DOR = 4.39, AUC = 0.7532 for POLE-mutant vs POLE-wild-type ECs; sensitivity = 0.85, specificity = 0.73, LR + =2.80, LR- = 0.22, DOR = 15.17 for POLE-mutant vs NSMP ECs; sensitivity = 0.85, specificity = 0.66, LR + =2.49, LR- = 0.25, DOR = 10.30 for POLE-mutant vs POLE-wild-type/MMR-proficient ECs; sensitivity = 0.68, specificity = 0.44, LR + =1.38, LR- = 0.64, DOR = 2.68, AUC = 0.6694 for POLE-mutant vs MMR-deficient ECs.

CONCLUSION

TIL-high pattern shows a moderate accuracy in distinguishing POLE-mutated from POLE-wild-type ECs after the exclusion of MMR-deficient cases. TIL might be considered in an integrate algorithm to identify POLE-mutated ECs when sequencing is unavailable. Further studies are necessary in this regard.

Endometrial cancer with a POLE mutation progresses frequently through the type I pathway despite its high-grade endometrioid morphology: a cohort study at a single institution in Japan

POLE-mutated endometrial cancer (EC) frequently shows high-grade endometrioid histology, which represents heterogeneity in the dualistic classification of EC. This study aimed to assess the clinicopathology and pathogenesis of POLE-mutated EC due to the scarcity of related information for Asian women. POLE variants were sequenced in tissues of Japanese women with EC. The tumor mutation burden (TMB) was assessed in tissues with a POLE variant of unknown significance. In the POLE-mutated EC tissues, the immunostaining expression of CD8, hormonal receptors, and p53 was evaluated, and the POLE variants in cancer and atypical endometrial hyperplasia (AEH) lesions were assessed by laser-capture microdissection. POLE variants were identified in five patients (3.9%) with high-grade endometrioid carcinoma among 127 patients with EC (S459F in two tissues and P441P in three tissues with a high TMB). The five cancer tissues coexisted with normal endometrium and/or AEH. Both AEH and cancer cells showed hormonal receptor positivity and harbored the same POLE mutation. Two patients showed a subclonal overexpression pattern of p53 in cancer and AEH lesions. In conclusion, POLE-mutated EC progresses through the type I pathway, even though it frequently shows high-grade endometrioid morphology. The common POLE mutation sites in EC might vary among races.

Impact of endometrial sampling technique and biopsy volume on the diagnostic accuracy of endometrial cancer

BACKGROUND

Histotype and tumor grading of endometrial cancer are the most important factors that have to be assessed by preoperative endometrial sampling, and their concordance with the final surgical and definitive histological findings is of paramount importance. We aim to compare histotype and tumor grading concordance of various endometrial sampling techniques (ESTs) and to investigate the role of endometrial volume biopsy.

METHODS

We performed a retrospective analysis of patients with apparent early stage endometrial cancer collecting demographic, clinical data, type of EST, pathological characteristics of endometrial biopsies and final specimens. We classified ESTs as dilation and curettage (D&C), diagnostic hysteroscopy with D&C, outpatient hysteroscopy and operative hysteroscopy with or without D&C. Diagnostic and operative hysteroscopy were performed with Bettocchi's 5 mm hysteroscope. We evaluated concordance for histotype, and tumor grading, and we performed subgroup analysis based on the technique and final tumor grading. Concordance was classified from good, moderate, sufficient, fair, poor and none using Cohen k-statistic. Finally, we investigated the existence of independent risk factors for discordant tumor grading using multivariate binary logistic regression.

RESULTS

We collected 148 patients and of these 131 (88.5%) were diagnosed with endometrioid histotype and 65 (44%), 46 (31%) and 37 (25%) respectively with well, moderate and poor differentiated tumors. Atypical hyperplasia (AH) was detected preoperatively in 28 patients (19%). Histotype concordance was fair (k=0.35) and tumor grading concordance was moderate (k=0.45); particularly, concordance was fair in well-differentiated cases (k=0.38); concordance was moderate in moderate- and poor-differentiated cases (k=0.52) and good (k=0.71). Operative hysteroscopy showed moderate concordance for histotype (k=0.41), while grading concordance was fair for G1 (k=0.41), moderate for G2 (k=0.58) and good for G3 (k=0.72), regardless the use of D&C. Preoperative volume biopsy did not impact the concordance of tumor grading, while the adoption of operative hysteroscopy (with or without D&C) decreased the risk of grading discordance in G3 tumors (HR 0.17; 95% CI: 0.03-0.94; P=0.04). Conversely, time elapsed from diagnosis to treatment in well-differentiated tumors increased the risk of discordant results (HR 1.06; 95% CI: 1.02-1.52; P=0.04).

CONCLUSIONS

Operative hysteroscopy demonstrated the best tumor grading concordance, especially in poor-differentiated tumors. The volume of biopsy did not affect the tumor grading concordance.

Immune Checkpoint Blockade in Gynecologic Cancers: State of Affairs

Simple Summary

Most endometrial cancer patients are diagnosed at an early stage, receive standard treatment, and survive well. Ovarian cancer has no specific symptoms and usually escapes diagnosis until the patient has advanced disease. This disease results in the highest number of deaths of gynecologic cancers. Current treatments for gynecologic cancers in the advanced stage are not sufficiently effective for good outcome in most patients. This review discusses two novel treatments, which are immune checkpoint inhibitor antibodies that block immune checkpoint molecules cytotoxic T lymphocyte associated protein-4 (CTLA-4) and programmed death-1 (PD-1) in patients. The antibody blocking of CTLA-4 or PD-1 alone is promising treatment for some categories of advanced disease endometrial cancer, but it has little effect against ovarian cancer. Our study primarily discusses the status of clinical trials for these two diseases and the biological parameters governing the different outcomes to these therapies. We also propose mechanisms whereby blocking CTLA-4 and PD-1 may be used in combination with other agents to give much better survival in advanced disease ovarian cancer patients.

Abstract

This review provides an update on the current use of immune checkpoint inhibitors (ICI) in female gynecologic cancers, and it addresses the potential of these agents to provide therapy options for disease management and long-term remission in advanced disease patients, where surgery, chemotherapy, and/or radiation fail to meet this goal. The topic of immune checkpoint inhibitors (ICI) blocking cytotoxic T lymphocyte associated protein-4 (CTLA-4) and the programmed death-1 (PD-1) axis has come to the forefront of translational medicine over the last decade for several malignancies. The text will focus primarily on a discussion of ovarian cancer, which is the most frequent cause of death of gynecologic cancers; endometrial cancer, which is the most often diagnosed gynecologic cancer; and cervical cancer, which is the third most common female gynecologic malignancy, all of which unfavorably alter the lives of many women. We will address the critical factors that regulate the outcome of these cancer types to ICI therapy, the ongoing clinical trials in this area, as well as the adverse immune responses that impact the outcome of patients given ICI regimens.

First description of ultramutated endometrial cancer caused by germline loss-of-function and somatic exonuclease domain mutations in POLE gene

Endometrial cancer (EC) harboring heterozygous POLE proofreading inactivating mutations (POLE-exo*) is associated with an increased number of somatic mutations that result in a distinctive anti-tumor immune response. However, the consequences of such POLE mutations in the context of the missing wild-type allele have not yet been described in endometrial tumors. A 72-year-old woman harboring a germline monoallelic frameshift mutation (p.Pro269fsTer26) in POLE was diagnosed with an EC having a somatic heterozygous mutation in the exonuclease domain of POLE (S459F). Targeted gene sequencing revealed an ultramutated phenotype (381 mutations/Mb) in the tumor and a 2-fold excess of mutations on the DNA leading strand. Additionally, we observed a mutational signature similar to the COSMIC signature 10, a higher mutation rate in this tumor than in endometrial tumors with heterozygous POLE-exo*, and an increased number of T lymphocytes. This is the first report of an ultramutated EC harboring a somatic POLE-exo* mutation in association with a germline loss-of-function mutation in this gene. The absence of a wild type POLE allele led to a particularly high mutational burden.

The frequency of POLE-mutation in endometrial carcinoma and prognostic implications: a systemic review and meta-analysis

Background

Endometrial carcinoma (EC) is classified into four distinct molecular subgroups including ultramutated DNA polymerase epsilon (POLE). POLE-mutated tumors have the best prognosis and are a promising target for immunotherapy. This meta-analysis consolidated the reported variation of POLE-mutant frequency and assessed prognostic value in EC.

Methods

Internet searches explored scientific data bases: EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials databases. Data was extracted from eligible studies including: sample size, number of positive POLE-mutant cases, sequencing information, clinicopathologic data, and survival data. Meta-analysis and a random-effects model produced pooled estimates of POLE frequency and prognostic parameters using 95% confidence intervals (CI), hazard ratios (HR), and odd ratios (OR).

Results

Six thousand three hundred and forty-six EC patient cases were pooled from 25 studies. The pooled proportion of POLE gene mutation in EC was 8.59% (95% CI, 7.01 to 10.32), of which 8.22% (95% CI, 6.27 to 10.42) were type I and 0.93% (95% CI, 0.34 to 1.81) type 2. Clinicopathologic data showed that POLE-mutated tumors are mostly endometrioid. They present at higher levels in earlier stages (I–II) of EC (89.51%; 95% CI, 81.11 to 95.66) at the highest grade III (51.53%; 95% CI, 36.08 to 66.84) with reduced myometrial invasion (OR, 1.48, 95% CI, 0.99 to 2.20). Survival analysis indicated favorable overall survival (HR, 0.90), disease-specific survival (HR, 0.41), and progression-free survival (HR, 0.23) for POLE mutant EC.

Conclusions

Almost one-tenth of EC patients have POLE-mutated tumors. Given their improved prognostic potential, identifying the POLE mutation status is key for the management of EC patients.

POLE mutation combined with microcystic, elongated and fragmented (MELF) pattern invasion in endometrial carcinomas might be associated with poor survival in Chinese women

OBJECTIVE

POLE mutation is a prognostic marker associated with excellent outcome in endometrial carcinoma (EC). However, these EC tumors frequently have aggressive histology. The aim of this study was to determine how to integrate the implications of POLE mutations into existing risk assessment strategies and further stratify patients.

METHODS

We detected POLE mutations in a cohort of 426 ECs from Chinese women and observed their prognostic significance in terms of survival and recurrence outcomes in combination with histological and other molecular characteristics, including microcystic, elongated and fragmented (MELF) pattern invasion, histologic subtype, tumor grade, myometrial invasion and p53 protein and mismatch repair protein expression status.

RESULTS

POLE mutations were identified in 38 of 426 ECs (8.9%). The most common mutations were P286R (31.6%), V411L (15.8%) and Q453R (15.8%). We confirmed that POLE mutation was associated with improved overall survival (P = .047), although it did not show a statistically significant relationship with progression-free survival (P = .45). Interestingly, further analyses indicated that in POLE-mutant tumors, MELF pattern invasion was associated with a 15.1-fold increase in tumor recurrence or progression risk (HR = 15.1, 95%CI = 1.57-145.3, P = .018), whereas this phenomenon was not present in the POLE-wild-type subgroup (HR = 0.90, 95%CI = 0.39-2.08, P = .80). Furthermore, higher staging and deeper myometrial invasion also showed much higher risk in patients harboring POLE mutations compared with those without POLE mutations.

CONCLUSIONS

Although POLE mutation was associated with favorable overall survival, the combined consideration of POLE mutation status and established clinicopathologic factors in the risk assessment of endometrial cancer is more accurate than the consideration of clinicopathologic factors alone and might lead to precise and individualized therapeutic strategies.

POLE Mutation Characteristics in a Chinese Cohort with Endometrial Carcinoma

Objective

To study the characteristics of polymerase epsilon (POLE) exonuclease domain mutations in Chinese patients with endometrial carcinoma (EC).

Methods

This study analyzed data from 529 patients with EC in The Cancer Genome Atlas (TCGA) and 467 EC patients evaluated at the Shanghai First Maternity and Infant Hospital (SFMIH). POLE mutation heterogeneity was analyzed in paired curettage and hysterectomy samples from 120 SFMIH patients. Sanger sequencing identified mutations in the POLE exonuclease domain, and correlations between POLE mutation status and various clinicopathological features were determined by chi-squared testing and Cohen’s kappa analysis, with Kaplan–Meier survival curves generated to assess correlations between POLE mutation status and overall survival (OS).

Results

Thirty-five mutations were identified in 467 samples (7.5%), and novel mutations were detected in the SFMIH cohort. Compared to the TCGA cohort, the SFMIH cohort had fewer POLE mutations when matched by age (<60) and histology (endometrioid) (p < 0.001 and p = 0.010, respectively). In our study cohort, POLE mutations were significantly associated with adjuvant treatment (p = 0.029), and patients with POLE mutations who underwent chemoradiotherapy had a poor OS (p < 0.0001). Notably, shorter OS was significantly associated with POLE mutations in hysterectomy samples from patients aged >60 years or with stage I disease in the paired curettage-hysterectomy group.

Conclusion

The significant difference in POLE mutation profiles between the TCGA and SFMIH cohorts, as well as the poor consistency between the curettage and hysterectomy samples, suggests that different parameters need to be applied to determine the prognosis of patients with EC in China.

ESMO recommendations on microsatellite instability testing for immunotherapy in cancer, and its relationship with PD-1/PD-L1 expression and tumour mutational burden: a systematic review-based approach

BACKGROUND

Cancers with a defective DNA mismatch repair (dMMR) system contain thousands of mutations most frequently located in monomorphic microsatellites and are thereby defined as having microsatellite instability (MSI). Therefore, MSI is a marker of dMMR. MSI/dMMR can be identified using immunohistochemistry to detect loss of MMR proteins and/or molecular tests to show microsatellite alterations. Together with tumour mutational burden (TMB) and PD-1/PD-L1 expression, it plays a role as a predictive biomarker for immunotherapy.

METHODS

To define best practices to implement the detection of dMMR tumours in clinical practice, the ESMO Translational Research and Precision Medicine Working Group launched a collaborative project, based on a systematic review-approach, to generate consensus recommendations on the: (i) definitions related to the concept of MSI/dMMR; (ii) methods of MSI/dMMR testing and (iii) relationships between MSI, TMB and PD-1/PD-L1 expression.

RESULTS

The MSI-related definitions, for which a consensus frame-work was used to establish definitions, included: 'microsatellites', 'MSI', 'DNA mismatch repair' and 'features of MSI tumour'. This consensus also provides recommendations on MSI testing; immunohistochemistry for the mismatch repair proteins MLH1, MSH2, MSH6 and PMS2 represents the first action to assess MSI/dMMR (consensus with strong agreement); the second method of MSI/dMMR testing is represented by polymerase chain reaction (PCR)-based assessment of microsatellite alterations using five microsatellite markers including at least BAT-25 and BAT-26 (strong agreement). Next-generation sequencing, coupling MSI and TMB analysis, may represent a decisive tool for selecting patients for immunotherapy, for common or rare cancers not belonging to the spectrum of Lynch syndrome (very strong agreement). The relationships between MSI, TMB and PD-1/PD-L1 expression are complex, and differ according to tumour types.

CONCLUSIONS

This ESMO initiative is a response to the urgent questions raised by the growing success of immunotherapy and provides also important insights on the relationships between MSI, TMB and PD-1/PD-L1.

An immune competent orthotopic model of endometrial cancer with metastasis

Endometrial cancer is the most common gynecologic malignancy in the U.S. with metastatic disease remaining the major cause of patient death. Therapeutic strategies have remained essentially unchanged for decades. A significant barrier to progression in treatment modalities stems from a lack of clinically applicable in vivo models to accurately mimic endometrial cancer; specifically, ones that form distant metastases and maintain an intact immune system. To address this problem, we have established the first immune competent murine orthotopic tumor model for metastatic endometrial cancer by creating a green fluorescent protein labeled cell line from an endometrial cancer that developed in a Pgr ^cre/+ Pten ^f/f Kras ^G12D genetically engineered mouse. These cancer cells were grafted into the abraded uterine lumen of ovariectomized recipient mice treated with estrogen and subsequently developed local and metastatic endometrial tumors. We noted primary tumor formation in 59% mixed background and 86% of C57BL/6 animals at 4 weeks and distant lung metastases in 78% of mice after 2 months. This immunocompetent orthotopic tumor model closely resembles some human metastatic endometrial cancer, modeling both local metastasis and hematogenous spread to lung and has significant potential to advance the study of endometrial cancer and its metastasis.

Interpretation of somatic POLE mutations in endometrial carcinoma

Pathogenic somatic missense mutations within the DNA polymerase epsilon (POLE) exonuclease domain define the important subtype of ultramutated tumours ('POLE-ultramutated') within the novel molecular classification of endometrial carcinoma (EC). However, clinical implementation of this classifier requires systematic evaluation of the pathogenicity of POLE mutations. To address this, we examined base changes, tumour mutational burden (TMB), DNA microsatellite instability (MSI) status, POLE variant frequency, and the results from six in silico tools on 82 ECs with whole-exome sequencing from The Cancer Genome Atlas (TCGA). Of these, 41 had one of five known pathogenic POLE exonuclease domain mutations (EDM) and showed characteristic genomic alterations: C>A substitution > 20%, T>G substitutions > 4%, C>G substitutions < 0.6%, indels < 5%, TMB > 100 mut/Mb. A scoring system to assess these alterations (POLE-score) was developed; based on their scores, 7/18 (39%) additional tumours with EDM were classified as POLE-ultramutated ECs, and the six POLE mutations present in these tumours were considered pathogenic. Only 1/23 (4%) tumours with non-EDM showed these genomic alterations, indicating that a large majority of mutations outside the exonuclease domain are not pathogenic. The infrequent combination of MSI-H with POLE EDM led us to investigate the clinical significance of this association. Tumours with pathogenic POLE EDM co-existent with MSI-H showed genomic alterations characteristic of POLE-ultramutated ECs. In a pooled analysis of 3361 ECs, 13 ECs with DNA mismatch repair deficiency (MMRd)/MSI-H and a pathogenic POLE EDM had a 5-year recurrence-free survival (RFS) of 92.3%, comparable to previously reported POLE-ultramutated ECs. Additionally, 14 cases with non-pathogenic POLE EDM and MMRd/MSI-H had a 5-year RFS of 76.2%, similar to MMRd/MSI-H, POLE wild-type ECs, suggesting that these should be categorised as MMRd, rather than POLE-ultramutated ECs for prognostication. This work provides guidance on classification of ECs with POLE mutations, facilitating implementation of POLE testing in routine clinical care. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

PD-L1 and CD4 are independent prognostic factors for overall survival in endometrial carcinomas

Background

Tumor microenvironment (TME) including the immune checkpoint system impacts prognosis in some types of malignancy. The aim of our study was to investigate the precise prognostic significance of the TME profile in endometrial carcinoma.

Methods

We performed immunohistochemistry of the TME proteins, PD-L1, PD-1, CD4, CD8, CD68, and VEGF in endometrial carcinomas from 221 patients.

Results

High PD-L1 in tumor cells (TCs) was associated with better OS (p = 0.004), whereas high PD-L1 in tumor-infiltrating immune cells (TICs) was associated with worse OS (p = 0.02). High PD-L1 in TICs correlated with high densities of CD8⁺ TICs and CD68⁺ TICs, as well as microsatellite instability (p = 0.00000064, 0.00078, and 0.0056), while high PD-L1 in TCs correlated with longer treatment-free interval (TFI) after primary chemotherapy in recurrent cases (p = 0.000043). High density of CD4⁺ TICs correlated with better OS and longer TFI (p = 0.0008 and 0.014). Univariate and multivariate analyses of prognostic factors revealed that high PD-L1 in TCs and high density of CD4⁺ TICs were significant and independent for favorable OS (p = 0.014 and 0.0025).

Conclusion

The current findings indicate that PD-L1 and CD4⁺ helper T cells may be reasonable targets for improving survival through manipulating chemosensitivity, providing significant implications for combining immunotherapies into the therapeutic strategy for endometrial carcinoma.

Early-stage endometrial cancer, CTNNB1 mutations, and the relation between lymphovascular space invasion and recurrence

INTRODUCTION

Women diagnosed with early-stage (FIGO 1) endometrial cancer, grade 1 and 2 can have a good prognosis. Most of these women can be treated successfully with a hysterectomy and bilateral salpingo-oophorectomy and without the additional adjuvant treatment that is accompanied by more risks for complications. However, when recurrence does occur, the consequences can be dire. Accurate decisions must therefore be made by surgeons to avoid either under- or over-treatment. Risk and patient stratification for tailoring treatment still need further improvement. Both histopathology and genetic variants could be integrated into the decision process if relevant factors were identified.

MATERIAL AND METHODS

Morphological features and the presence of selected genetic mutations in isolated malignant endometrial epithelial cells from these tumors were analyzed in a strictly defined cohort of FIGO 1, grade 1 and 2 low-risk endometrial cancer. Their presence in this cohort, their relation to recurrence, and the association between histopathological features and mutations were determined. This analysis was performed using archival formalin-fixed paraffin-embedded tissue, complete re-evaluation of histopathological features, laser capture microdissection of epithelial cells, and a polymerase chain reaction-based mutational screening assay.

RESULTS

Twenty-one women with recurrence, after initial identification as low-risk endometrial cancer, were compared with 20 matched control women. The histological marker of lymphovascular invasion was significantly associated with recurrence. There was also a very high prevalence of mutations in CTNNB1 gene, occurring in 50% of this cohort. PTEN mutations were also observed in 27.8% of cases and PIK3CA mutations in 22.2%; none of these mutations were significantly related to recurrence.

CONCLUSIONS

This study supports the importance of lymphovascular space invasion to identify women with significant risk for recurrence in initially low-risk, early-stage endometrial cancer. It also identifies CTNNB1 as a significant mutation in early-stage disease, and although it may not represent a marker for recurrence its high prevalence in early stage disease could have relevance for both pathogenesis and early treatment.

Germline POLE mutation in a child with hypermutated medulloblastoma and features of constitutional mismatch repair deficiency

Ultra-hypermutation (>100 mutations/Mb) is rare in childhood cancer genomes and has been primarily reported in patients with constitutional mismatch repair deficiency (CMMRD) caused by biallelic germline mismatch repair (MMR) gene mutations. We report a 5-yr-old child with classic clinical features of CMMRD and an ultra-hypermutated medulloblastoma with retained MMR protein expression and absence of germline MMR mutations. Mutational signature analysis of tumor panel sequencing data revealed a canonical DNA polymerase-deficiency-associated signature, prompting further genetic testing that uncovered a germline POLE p.A456P missense variant, which has previously been reported as a recurrent somatic driver mutation in cancers. This represents the earliest known onset of malignancy in a patient with a germline mutation in the POLE proofreading polymerase. The clinical features in this child, virtually indistinguishable from those of CMMRD, suggest that polymerase-proofreading deficiency should be considered in the differential diagnosis of CMMRD patients with retained MMR function.

Clinical actionability of molecular targets in endometrial cancer

Endometrial cancer accounts for ~76,000 deaths among women each year worldwide. Disease mortality and the increasing number of new diagnoses make endometrial cancer an important consideration in women's health, particularly in industrialized countries, where the incidence of this tumour type is highest. Most endometrial cancers are carcinomas, with the remainder being sarcomas. Endometrial carcinomas can be classified into several histological subtypes, including endometrioid, serous and clear cell carcinomas. Histological subtyping is currently used routinely to guide prognosis and treatment decisions for endometrial cancer patients, while ongoing studies are evaluating the potential clinical utility of molecular subtyping. In this Review, we summarize the overarching molecular features of endometrial cancers and highlight recent studies assessing the potential clinical utility of specific molecular features for early detection, disease risk stratification and directing targeted therapies.

The impact of programmed cell death-ligand 1 (PD-L1) and CD8 expression in grade 3 endometrial carcinomas

BACKGROUND

To evaluate the expression of programmed cell death-ligand 1 (PD-L1) and CD8 in high-grade endometrial carcinomas and relate it to several clinicopathological parameters.

METHODS

One hundred and one (101) patients with high-grade endometrial carcinomas who were completely surgically staged were included in this study. PD-L1 and CD8 + expression was evaluated by immunohistochemistry.

RESULTS

In our cohort, 47 women (46.5%) had endometrioid carcinomas and 54 patients (53.5%) were diagnosed with non-endometrioid cancers. In endometrioid carcinomas, there was a significantly higher rate of positivity for PD-L1 expression (p = 0.042) and of intraepithelial CD8 + cell counts (p = 0.004) as opposed to non-endometrioid cancers. There were no significant relationships with any of the other clinicopathological features under study. Univariate and multivariate analysis revealed that only high intraepithelial CD8 + counts (p = 0.01) was associated with longer progression-free survival. Tumors positive for PD-L1 and high intraepithelial CD8 expression were mainly of endometrioid histology, whilst PD-L1-positive/CD8 low and PD-L1-negative/CD8 low tumors were mostly non-endometrioid carcinomas (p = 0.01). PD-L1 negative/CD8 high tumors had the longest progression-free survival (p = 0.032).

CONCLUSIONS

In grade 3 endometrial carcinomas, both of endometrioid and non-endometrioid type, high intraepithelial CD8 + counts represent an independent favorable prognostic factor and when related to PD-L1-negative tumors, a longer progression-free survival can be predicted. Immunotherapy could probably be considered for PD-L1-positive/CD8 + high tumors, which were mostly of endometrioid histology.

Endometrial Tumor Microenvironment Alters Human NK Cell Recruitment, and Resident NK Cell Phenotype and Function

Endometrial Cancer is the most common cancer in the female genital tract in developed countries, and with its increasing incidence due to risk factors such as aging and obesity tends to become a public health issue. However, its immune environment has been less characterized than in other tumors such as breast cancers. NK cells are cytotoxic innate lymphoid cells that are considered as a major anti-tumoral effector cell type which function is drastically altered in tumors which participates to tumor progression. Here we characterize tumor NK cells both phenotypically and functionally in the tumor microenvironment of endometrial cancer. For that, we gathered endometrial tumors, tumor adjacent healthy tissue, blood from matching patients and healthy donor blood to perform comparative analysis of NK cells. First we found that NK cells were impoverished in the tumor infiltrate. We then compared the phenotype of NK cells in the tumor and found that tumor resident CD103⁺ NK cells exhibited more co-inhibitory molecules such as Tigit, and TIM-3 compared to recruited CD103⁻ NK cells and that the expression of these molecules increased with the severity of the disease. We showed that both chemokines (CXCL12, IP-10, and CCL27) and cytokines profiles (IL-1β and IL-6) were altered in the tumor microenvironment and might reduce NK cell function and recruitment to the tumor site. This led to hypothesize that the tumor microenvironment reduces resident NK cells cytotoxicity which we confirmed by measuring cytotoxic effector production and degranulation. Taken together, our results show that the tumor microenvironment reshapes NK cell phenotype and function to promote tumor progression.

Diagnosis and management of a recurrent polymerase-epsilon (POLE)-mutated endometrial cancer

Polymerase-epsilon (POLE)-mutated carcinomas are a rare, but well-known subtype of endometrial cancer. While typically associated with good prognosis, recurrences are documented. Here we present a case of recurrent POLE-mutated endometrial cancer, discuss pathologic features, current methods of molecular classification, and explore therapeutic implications for the POLE-mutation phenotype.

Phenotype of POLE-mutated endometrial cancer

Background and purpose

Individualized therapy in endometrial cancer, the most common gynaecologic cancer in the developed world, focuses on identifying specific molecular subtypes. Mutations in the exonuclease domain of the DNA polymerase epsilon (POLE) gene define one such subtype, which causes an ultra-mutated tumour phenotype. These tumours may have an improved progression-free survival and may be receptive to specific therapies. However, the clinical phenotype of these tumours is unknown. The objective of this study was to evaluate the clinical and genetic features of POLE-mutated tumours from a large cohort of women whose cases are characterized by: (1) the availability of detailed clinical and lifestyle data; (2) mutation analysis; and (3) long-term follow-up.

Methods

A total of 604 patients with endometrial cancer were included in the study. Data from a detailed questionnaire, including lifestyle and family history information, provided extensive pertinent information on the patients. Sequencing of exons 9–14 of the POLE gene was performed. Follow-up data were gathered and analysed.

Results

Hotspot pathogenic POLE mutations were identified in N = 38/599 patients (6.3%). Patients with a POLE-mutated tumour were significantly younger, were more often nulliparous, and had a history of smoking. POLE-mutated tumours were more frequently aneuploid. Prognosis for patients with hotspot POLE-mutated tumours was significantly better in comparison with patients with non-mutated tumours; however careful selection of pathogenic mutations is essential to the definition of this prognostically favourable group.

Conclusions

This study demonstrates that POLE-mutated endometrial cancer is significantly associated with previously unknown clinicopathologic characteristics. Outcome in POLE-mutated tumours was excellent in cases with hotspot mutations. Our results suggest that prediction of excellent outcome in cases of POLE-mutated EMCA should be restricted to cases of EMCA with hotspot mutations until further data are available on the rising number of mutations with unknown significance.

POLE-mutated clear cell cervical cancer associated with in-utero diethylstilbestrol exposure

We report an extraordinary case of a woman, exposed to diethylstilbestrol in utero, who developed clear cell adenocarcinoma of the cervix with a concurrent polymerase-Ɛ (POLE) somatic mutation. The tumor exhibited the classic phenotypic characteristics of POLE-mutated tumors originating from other organs (e.g. the uterus or the colon) including increased tumor infiltrating lymphocytes and high PD-L1 expression and has remained in remission since completion of primary therapy for >4 years. This case highlights the importance of next generation sequencing in unraveling the biology of rare tumors and supports that the presence of a POLE mutation and the associated ultramutated state confers a unique phenotype of higher immunogenicity and possibly improved prognosis in a tissue-agnostic manner, i.e. regardless of the type of cancer where the POLE mutation is present.

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We report a POLE-mutated clear cell cervical cancer associated with in-utero DES.

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Tumor exhibited increased tumor infiltrating lymphocytes and PD-L1 expression.

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Patient remains in remission for ≥4 years after standard therapy.

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POLE mutation confers a phenotype of higher immunogenicity and improved outcome.

Molecular Genetics of Endometrial Carcinoma

Endometrial cancer is the most commonly diagnosed gynecologic malignancy in the United States. Endometrioid endometrial carcinomas constitute approximately 85% of newly diagnosed cases; serous carcinomas represent approximately 3-10% of diagnoses; clear cell carcinoma accounts for <5% of diagnoses; and uterine carcinosarcomas are rare, biphasic tumors. Longstanding molecular observations implicate PTEN inactivation as a major driver of endometrioid carcinomas; TP53 inactivation as a major driver of most serous carcinomas, some high-grade endometrioid carcinomas, and many uterine carcinosarcomas; and inactivation of either gene as drivers of some clear cell carcinomas. In the past decade, targeted gene and exome sequencing have uncovered additional pathogenic aberrations in each histotype. Moreover, an integrated genomic analysis by The Cancer Genome Atlas (TCGA) resulted in the molecular classification of endometrioid and serous carcinomas into four distinct subgroups, POLE (ultramutated), microsatellite instability (hypermutated), copy number low (endometrioid), and copy number high (serous-like). In this review, we provide an overview of the major molecular features of the aforementioned histopathological subtypes and TCGA subgroups and discuss potential prognostic and therapeutic implications for endometrial carcinoma.

Adjuvant Treatment for POLE Proofreading Domain-Mutant Cancers: Sensitivity to Radiotherapy, Chemotherapy, and Nucleoside Analogues

Purpose: Pathogenic POLE proofreading domain mutations are found in many malignancies where they are associated with ultramutation and favorable prognosis. The extent to which this prognosis depends on their sensitivity to adjuvant treatment is unknown, as is the optimal therapy for advanced-staged or recurrent POLE-mutant cancers.Experimental Design: We examined the recurrence-free survival of women with POLE-mutant and POLE-wild-type endometrial cancers (EC) in the observation arm of the randomized PORTEC-1 endometrial cancer trial (N = 245 patients with stage I endometrial cancer for analysis). Sensitivity to radiotherapy and selected chemotherapeutics was compared between Pole-mutant mouse-derived embryonic stem (mES) cells, generated using CRISPR-Cas9 (Pole mutations D275A/E275A, and cancer-associated P286R, S297F, V411L) and isogenic wild-type cell lines.Results: In the observation arm of the PORTEC-1 trial (N = 245), women with POLE-mutant endometrial cancers (N = 16) had an improved recurrence-free survival (10-year recurrence-free survival 100% vs. 80.1% for POLE-wild-type; HR, 0.143; 95% confidence interval, 0.001-0.996; P = 0.049). Pole mutations did not increase sensitivity to radiotherapy nor to chemotherapeutics in mES cells. In contrast, Pole-mutant cells displayed significantly increased sensitivity to cytarabine and fludarabine (IC50Pole P286R-mutant vs. wild-type: 0.05 vs. 0.17 μmol/L for cytarabine, 4.62 vs. 11.1 μmol/L for fludarabine; P < 0.001 for both comparisons).Conclusions: The favorable prognosis of POLE-mutant cancers cannot be explained by increased sensitivity to currently used adjuvant treatments. These results support studies exploring minimization of adjuvant therapy for early-stage POLE-mutant cancers, including endometrial and colorectal cancers. Conversely, POLE mutations result in hypersensitivity to nucleoside analogues, suggesting the use of these compounds as a potentially effective targeted treatment for advanced-stage POLE-mutant cancers. Clin Cancer Res; 24(13); 3197-203. ©2018 AACR.

Tumor Mutational Burden Guides Therapy in a Treatment Refractory POLE-Mutant Uterine Carcinosarcoma

Gynecologic carcinosarcomas, previously known as malignant mixed Müllerian tumors, are uncommon malignancies that demonstrate an aggressive biology and lack a standard therapeutic approach. Molecular analyses have revealed recurrent alterations in chromatin remodeling genes, but clinical support for therapeutic significance is lacking. We prospectively identified a patient with refractory uterine carcinosarcoma whose tumor was subject to molecular profiling at diagnosis and again at radiographic progression. Initial molecular testing did not assess tumor mutational burden, DNA polymerase ɛ (POLE), or microsatellite status. After the failure of several lines of chemotherapy, comprehensive genomic profiling of a repeat biopsy identified two missense mutations of the exonuclease domain of POLE (P286R and T323A). Tumor mutational burden was elevated (169 mutations per DNA megabase), consistent with an ultramutator phenotype. As seen in previously reported POLE-endometrioid cases, our patient harbored alterations in PIK3CA, ARID1A, and PTEN and was microsatellite stable, with appreciable tumor-infiltrating lymphocytes. She achieved an ongoing durable response with pembrolizumab. This is the first report of programmed cell death protein 1 response in uterine carcinosarcoma.

KEY POINTS

Uterine carcinosarcoma is an uncommon and aggressive histologic variant of endometrial carcinoma with a poor prognosis.Inactivating DNA polymerase ɛ (POLE) mutations have been associated with high tumor mutational burden (TMB) and response to immune checkpoint inhibition.To the authors' knowledge, this is the first report of response to immune checkpoint inhibitor therapy in a patient with uterine carcinosarcoma.This case further supports expanding genomic profiling to include assessment of tumor mutational burden across tumor types, given the potential for immune checkpoint inhibitor therapy in TMB-high tumors.

Does a p53 "Wild-type" Immunophenotype Exclude a Diagnosis of Endometrial Serous Carcinoma?

An aberrant p53 immunophenotype may be identified in several histotypes of endometrial carcinoma, and is accordingly recognized to lack diagnostic specificity in and of itself. However, based on the high frequency with which p53 aberrations have historically been identified in endometrial serous carcinoma, a mutation-type immunophenotype is considered to be highly sensitive for the histotype. Using an illustrative case study and a review of the literature, we explore a relatively routine diagnostic question: whether the negative predictive value of a wild-type p53 immunophenotype for serous carcinoma is absolute, that is, whether a p53-wild type immunophenotype is absolutely incompatible with a diagnosis of serous carcinoma. The case is an advanced stage endometrial carcinoma that was reproducibly classified by pathologists from 3 institutions as serous carcinoma based on its morphologic features. By immunohistochemistry, the tumor was p53-wild type (DO-7 clone), diffusely positive for p16 (block positivity), and showed retained expression of PTEN, MSH2, MSH6, MLH1, and PMS2. Next generation sequencing showed that there indeed was an underlying mutation in TP53 (D393fs*78, R213*). The tumor was microsatellite stable, had a low mutational burden (4 mutations per MB), and displayed no mutations in the exonuclease domain of DNA polymerase epsilon (POLE) gene. Other genomic alterations included RB1 mutation (R46fs*19), amplifications in MYST3 and CRKL, and ARID1A deletion (splice site 5125-94_5138del108). A review of the recent literature identified 5 studies in which a total of 259 cases of serous carcinoma were whole-exome sequenced. The average TP53 mutational rate in endometrial serous carcinoma was only 75% (range, 60 to 88). A total of 12 (33%) of 36 immunohistochemical studies reported a p53-aberrant rate of <80% in endometrial serous carcinoma. We discuss in detail several potential explanations that may underlie the scenario of serous carcinoma-like morphology combined with p53-wild-type immunophenotype, including analytic limitations, a nonserous histotype displaying morphologic mimicry of serous carcinoma, and true biological phenomena (including the possibility of a TP53-independent pathway of endometrial serous carcinogenesis). Ultimately, our central thematic question is provisionally answered in the negative. At present, the available data would not support a categorical conclusion that a p53 alteration is a necessary and obligate component in the genesis and/or diagnosis of endometrial serous carcinoma. On the basis of their collective experience, the authors proffer some recommendations on the use of p53 immunohistochemistry in the histotyping of endometrial carcinomas.

Potential role of radiation therapy in augmenting the activity of immunotherapy for gynecologic cancers

Immune checkpoint inhibitors have become an area of intense interest in oncology and are actively being studied in a variety of cancer types with a wide range of success. In vitro data suggest mechanisms by which radiation can activate the immune system, and ongoing studies are exploring the potential interaction of checkpoint inhibitors with radiotherapy in both preclinical and clinical settings. Gynecologic malignancies are a heterogeneous group of tumors with varying prognoses, intrinsic immunogenicity, and potential for response to immune-based therapies. In this review, we focus on the rationale for immunotherapy and opportunities for augmentation by photon radiotherapy in cancers of the cervix, endometrium, and ovary.