CCNE1 and survival of patients with tubo-ovarian high-grade serous carcinoma: An Ovarian Tumor Tissue Analysis consortium study.

BACKGROUND: Cyclin E1 (CCNE1) is a potential predictive marker and therapeutic target in tubo-ovarian high-grade serous carcinoma (HGSC). Smaller studies have revealed unfavorable associations for CCNE1 amplification and CCNE1 overexpression with survival, but to date no large-scale, histotype-specific validation has been performed. The hypothesis was that high-level amplification of CCNE1 and CCNE1 overexpression, as well as a combination of the two, are linked to shorter overall survival in HGSC. METHODS: Within the Ovarian Tumor Tissue Analysis consortium, amplification status and protein level in 3029 HGSC cases and mRNA expression in 2419 samples were investigated. RESULTS: High-level amplification (>8 copies by chromogenic in situ hybridization) was found in 8.6% of HGSC and overexpression (>60% with at least 5% demonstrating strong intensity by immunohistochemistry) was found in 22.4%. CCNE1 high-level amplification and overexpression both were linked to shorter overall survival in multivariate survival analysis adjusted for age and stage, with hazard stratification by study (hazard ratio [HR], 1.26; 95% CI, 1.08-1.47, p = .034, and HR, 1.18; 95% CI, 1.05-1.32, p = .015, respectively). This was also true for cases with combined high-level amplification/overexpression (HR, 1.26; 95% CI, 1.09-1.47, p = .033). CCNE1 mRNA expression was not associated with overall survival (HR, 1.00 per 1-SD increase; 95% CI, 0.94-1.06; p = .58). CCNE1 high-level amplification is mutually exclusive with the presence of germline BRCA1/2 pathogenic variants and shows an inverse association to RB1 loss. CONCLUSION: This study provides large-scale validation that CCNE1 high-level amplification is associated with shorter survival, supporting its utility as a prognostic biomarker in HGSC.

Increased FOXJ1 protein expression is associated with improved overall survival in high-grade serous ovarian carcinoma: an Ovarian Tumor Tissue Analysis Consortium Study.

BACKGROUND: Recently, we showed a >60% difference in 5-year survival for patients with tubo-ovarian high-grade serous carcinoma (HGSC) when stratified by a 101-gene mRNA expression prognostic signature. Given the varied patient outcomes, this study aimed to translate prognostic mRNA markers into protein expression assays by immunohistochemistry and validate their survival association in HGSC. METHODS: Two prognostic genes, FOXJ1 and GMNN, were selected based on high-quality antibodies, correlation with protein expression and variation in immunohistochemical scores in a preliminary cohort (n = 134 and n = 80, respectively). Six thousand four hundred and thirty-four (FOXJ1) and 5470 (GMNN) formalin-fixed, paraffin-embedded ovarian neoplasms (4634 and 4185 HGSC, respectively) represented on tissue microarrays from the Ovarian Tumor Tissue Analysis consortium underwent immunohistochemical staining and scoring, then univariate and multivariate survival analysis. RESULTS: Consistent with mRNA, FOXJ1 protein expression exhibited a linear, increasing association with improved overall survival in HGSC patients. Women with >50% expression had the most favourable outcomes (HR = 0.78, 95% CI 0.67-0.91, p < 0.0001). GMNN protein expression was not significantly associated with overall HSGC patient survival. However, HGSCs with >35% GMNN expression showed a trend for better outcomes, though this was not significant. CONCLUSION: We provide foundational evidence for the prognostic value of FOXJ1 in HGSC, validating the prior mRNA-based prognostic association by immunohistochemistry.

Survey of NF1 inactivation by surrogate immunohistochemistry in ovarian carcinomas.

OBJECTIVE: Inhibition of the MAPK pathway by MEK inhibitors (MEKi) is currently a therapeutic standard in several cancer types, including ovarian low-grade serous carcinoma (LGSC). A common MAPK pathway alteration in tubo-ovarian high-grade serous carcinoma (HGSC) is the genomic inactivation of neurofibromin 1 (NF1). The primary objectives of our study were to survey the prevalence of NF1 inactivation in the principal ovarian carcinoma histotype as well as to evaluate its associations with clinico-pathological parameters and key biomarkers including BRCA1/2 status in HGSC. METHODS: A recently commercialized NF1 antibody (clone NFC) was orthogonally validated on an automated immunohistochemistry (IHC) platform and IHC was performed on tissue microarrays containing 2140 ovarian carcinoma cases. Expression was interpreted as loss/inactivated (complete or subclonal) versus normal/retained. RESULTS: Loss of NF1 expression was detected in 250/1429 (17.4%) HGSC including 11% with subclonal loss. Survival of NF1-inactivated HGSC patients was intermediate between favorable BRCA1/2 mutated HGSC and unfavorable CCNE1 high-level amplified HGSC. NF1 inactivation was mutually exclusive with CCNE1 high-level amplifications, co-occurred with RB1 loss and occurred at similar frequencies in BRCA1/2 mutated versus wild-type HGSC. NF1 loss was found in 21/286 (7.3%) endometrioid carcinomas with a favorable prognostic association (p = 0.048), and in 4/64 (5.9%) LGSC, mutually exclusive with other driver events. CONCLUSIONS: NF1 inactivation occurs in a significant subset of BRCA1/2 wild-type HGSC and a subset of LGSC. While the functional effects of NF1 inactivation need to be further characterized, this signifies a potential therapeutic opportunity to explore targeting NF1 inactivation in these tumors.

Prognostic and Theranostic Biomarkers in Ovarian Clear Cell Carcinoma.

In this study, we aimed to test whether prognostic biomarkers can achieve a clinically relevant stratification of patients with stage I ovarian clear cell carcinoma (OCCC) and to survey the expression of 10 selected actionable targets (theranostic biomarkers) in stage II to IV cases. From the population-based Alberta Ovarian Tumor Type study, 160 samples of OCCC were evaluated by immunohistochemistry and/or silver-enhanced in situ hybridization for the status of 5 prognostic (p53, p16, IGF2BP3, CCNE1, FOLR1) and 10 theranostic biomarkers (ALK, BRAF V600E, ERBB2, ER, MET, MMR, PR, ROS1, NTRK1-3, VEGFR2). Kaplan-Meier survival analyses were performed. Cases with abnormal p53 or combined p16/IFG2BP3 abnormal expression identified a small subset of patients (6/54 cases) with stage I OCCC with an aggressive course (5-yr ovarian cancer-specific survival of 33.3%, compared with 91.5% in the other stage I cases). Among theranostic targets, ERBB2 amplification was present in 11/158 (7%) of OCCC, while MET was ubiquitously expressed in OCCC similar to a variety of normal control tissues. ER/PR showed a low prevalence of expression. No abnormal expression was detected for any of the other targets. We propose a combination of 3 biomarkers (p53, p16, IGF2BP3) to predict prognosis and the potential need for adjuvant therapy for patients with stage I OCCC. This finding requires replication in larger cohorts. In addition, OCCC could be tested for ERBB2 amplification for inclusion in gynecological basket trials targeting this alteration.

Equivalent Survival of p53 Mutated Endometrial Endometrioid Carcinoma Grade 3 and Endometrial Serous Carcinoma.

TP53 status is the most important prognostic biomarker in endometrial carcinoma. We asked the question whether p53 mutated endometrial endometrioid carcinomas grade 3 (EEC3) or endometrial serous carcinomas (ESC), the latter ubiquitously harboring TP53 mutation, have different outcomes. TP53 mutation status was assessed by surrogate p53 immunohistochemistry on 326 EEC3 and ESC from 2 major cancer centers in Canada. Mutant-type p53 expression, including overexpression, complete absence, or cytoplasmic expression, was distinguished from the wild-type pattern. Statistical associations with clinico-pathological parameter, other key biomarkers, and survival analyses were performed. P53 mutant-type immunohistochemistry was observed in all 126 ESC and in 47/200 (23.5%) EEC3. ESC and p53 mutated EEC3 had an unfavorable outcome compared with p53 wild-type EEC3 (hazard ratio=2.37, 95% confidence interval=1.48-3.80, P=0.003, hazard ratio=2.19, 95% confidence interval=1.16-4.12, P=0.016, respectively) in multivariable analyses adjusted for age, stage, center, and presence of lymph-vascular invasion. There was no significant difference in survival between ESC and p53 mutated EEC3 in multivariable analysis. Furthermore, p53 mutated EEC3 and ESC almost completely overlapped in univariate survival analysis when mismatch repair (MMR)-deficient cases were excluded, which suggests that EEC3 harboring combined MMR deficiency and TP53 mutations behave more according to the MMR status. Significant differences between p53 mutated MMR-proficient EEC3 and ESC in PTEN and p16 expression status remained. p53 mutated, MMR-proficient EEC3 and ESC have overlapping survival significantly different from p53 wild-type EEC3, which justifies a similar treatment with current non-targeted standard therapy. Although this is so, separate classification should continue due to biological differences that will become important for future targeted therapy.

Molecular alterations in indolent, aggressive and recurrent ovarian low-grade serous carcinoma.

AIMS: The clinical courses of patients with low-grade serous carcinoma (LGSC) can be substantially different. The purpose of this study was to explore whether molecular or pathological features could identify patients who follow a more aggressive course. METHODS AND RESULTS: Twenty-six primary LGSCs (11 with an aggressive clinical course, and 15 with an indolent clinical course) and five paired recurrences were assessed for non-synonymous somatic mutations in 18 MAPK pathway genes and in 42 other classic cancer 'hotspot' genes by use of a custom-designed AmpliSeq panel based on the AmpliSeq Cancer hotspot panel v2. Copy number alterations for 94 target genes were assessed with the nCounter v2 Cancer CN assay. Immunohistochemistry for 12 proteins was performed. We detected 16 mutations in 13 of 26 cases (50%), affecting five genes that signal through the MAPK pathway, and one ESR1 mutation implicated in resistance to endocrine therapy in breast cancer. Recurrent samples were concordant with the primary tumour with respect to the mutational status, but all five cases showed additional alterations at the copy number or protein expression level. The absence of progesterone receptor (PR) expression and the presence of myometrial lymphovascular invasion were associated with an unfavourable outcome (log-rank P = 0.016 and P < 0.0001, respectively), but none of the other molecular features assessed showed an association. CONCLUSION: Despite limited case numbers, it appears that current molecular testing is inferior to a pathological parameter or protein expression in predicting the outcome of LGSCs. Prediction of outcome based on the primary tumour may be confounded by additional changes acquired over time.

Immunohistochemical Profiling of Endometrial Serous Carcinoma.

Endometrial serous carcinoma (ESC) is an aggressive neoplasm mainly seen in older women. The objective of this study was to refine immunohistochemical (IHC) panels for the differential diagnoses against endometrial endometrioid grade 3 (EC3), endometrial clear cell, and ovarian high-grade serous carcinoma as well as exploring the prognostic role of selected IHC markers. Fifty-two ESC from a single institution were assessed for 20 IHC markers, including ARID1A, CCNE1, CDKN2A, ERBB2, ESR1, HNF1B, FBXW7, IGF2BP3, MLH1, MSH2, MSH6, NAPSA, PAX8, PGR, PMS2, PTEN, TFF3, TP53, VIM, and WT1. ERBB2 chromogenic in situ hybridization was evaluated on tissue microarrays. Statistical analysis was performed. All ESC showed aberrant TP53, normal mismatch repair protein, and retained ARID1A and PTEN expression. ESR1 expression was present in 80% of ESC. A combination of TP53, PTEN, and CDKN2A had a sensitivity of 93.6% [95% confidence interval (CI), 84%-98%] and specificity of 87.8% (95% CI, 75%-95%) for ESC versus EC3. A combination of NAPSA and ESR1 had a sensitivity of 97.9% (95% CI, 89%-99%) and specificity of 72.2% (95% CI, 46%-90%) for ESC versus clear cell carcinoma. Absence of WT1 alone had a sensitivity of 66.0% (95% CI, 51%-79%) and specificity of 98.0% (95% CI, 94%-99%) for ESC versus ovarian high-grade serous carcinoma. Among all 52 ESCs, ERBB2 amplification was present in 23%, FBXW7 expression was absent in 10%, and CCNE1 was overexpressed in 59%, however, none were associated with prognosis. Our data support the value of IHC marker panels for histotyping of high-grade endometrial carcinomas.

Progesterone receptor expression is associated with longer overall survival within high-grade histotypes of endometrial carcinoma: A Canadian high risk endometrial cancer consortium (CHREC) study.

OBJECTIVE: To assess the association of hormone receptor expression with outcome in high-grade endometrial carcinomas. METHODS: This study included three sites participating in the Canadian High Risk Endometrial Cancer (CHREC) consortium. Sections from tissue microarrays containing cases with a diagnosis of endometrioid grade 3 (EC3) and endometrial serous carcinoma (ESC) were assessed for estrogen (ER) and progesterone receptor (PR) expression by immunohistochemistry. Expression was considered present if >1% of tumor cell nuclei were labeled. Associations with overall survival were assessed. RESULTS: ER expression was present in 168/216 (78%) of EC3 and 124/192 (65%) of ESC. PR expression was present in 148/212 (70%) of EC3 and 83/196 (42%) of ESC. PR expression was significantly associated with favorable overall survival in EC3 and ESC (log rank, p=0.018 and p=0.0024) but ER expression was not. PR expression was significantly associated with favorable overall survival in EC3 independent of age, stage, center and lymph-vascular invasion (hazard ratio=0.457, 95% CI 0.257-0.811, p=0.0075) as well as in stage I and II ESC (hazard ratio=0.266, 95% CI 0.094-0.750, p=0.0123). CONCLUSION: Our data provide support for the assessment of the PR expression status in EC3 and ESC. Future work will be required to determine how PR expression may be incorporated into management of patients with EC3 and ESC.

The Canadian Gynaecologic Oncology Perioperative Management Survey: Baseline Practice Prior to Implementation of Enhanced Recovery After Surgery (ERAS) Society Guidelines.

OBJECTIVE: To survey the current practice of Society of Gynecologic Oncology of Canada (GOC) members about preoperative, intraoperative, and postoperative phases of care. The survey was carried out prior to publication of the Enhanced Recovery After Surgery (ERAS) Society gynaecologic/oncology guidelines. METHODS: A survey was developed by the GOC and distributed to all surgical members between September and December 2015. RESULTS: The survey was completed by 77 of 92 practising gynaecologic oncologists (84%), representing 19 centres in 16 cities across Canada. Only 14.3% of respondents counselled their patients to stop smoking and drinking four weeks before surgery, while 41.6% routinely counselled patients to stop taking oral contraceptive pills. Approximately half of respondents (44.7%) prescribed preoperative mechanical bowel preparation. Over two thirds (67.5%) asked their patients not to eat solid foods after midnight on the day of surgery, and 19.5% recommended carbohydrate loading. Venous thromboembolism prophylaxis was given prior to laparotomy by 85.7% of participants overall, and by 67.6% prior to laparoscopy. The majority of respondents did not routinely use nasogastric tubes or intra-abdominal drains. The preferred modality for postoperative pain control after laparotomy was patient-controlled analgesia with narcotics (66.2%); only 29.9% chose epidural analgesia. Over half of respondents (56.6%) prescribed a progressive diet after surgery, while 42.1% recommended starting on an immediate standard diet postoperatively. CONCLUSION: The responses to this survey show wide variations in practice in the perioperative phases of surgical care. Implementation of the ERAS Society gynaecologic/oncology guidelines should help integrate evidence-based knowledge into practice, align perioperative care, and minimize practice variations, resulting in improved outcomes for patients.

PIK3CA missense mutation is associated with unfavorable outcome in grade 3 endometrioid carcinoma but not in serous endometrial carcinoma.

OBJECTIVE: To evaluate the outcome association of PIK3CA mutational status within histological types of rigorously classified high-grade endometrial carcinomas. METHODS: We assessed PIK3CA mutational status in exon 9 and exon 20 hot spots by Sanger sequencing of DNA derived from formalin fixed paraffin embedded tissue of 57 grade 3 endometrioid, 26 serous, 11 clear cell and 5 dedifferentiated carcinomas. We correlated PIK3CA mutation status with clinicopathological and other molecular parameters. Univariate and multivariate disease specific survival analysis was performed using Kaplan-Meier and Cox regression analyses. RESULTS: PIK3CA exon 9 or exon 20 missense mutations were identified in 20 of 99 (20%) high-grade endometrial carcinomas without significant difference across histological types (p=0.22). Presence of PIK3CA exon 9 or exon 20 missense mutations was associated with shorter disease specific survival within grade 3 endometrioid (p=0.0029) but not endometrial serous (p=0.57) carcinoma based on univariate analysis. Within grade 3 endometrioid carcinoma, PIK3CA exon 9 or exon 20 missense mutations were more commonly observed in cases that were deficient for mismatch repair protein expression (p=0.0058) and showed loss of ARID1A expression (p=0.037). CONCLUSIONS: PIK3CA exon 9 or exon 20 missense mutations are present across all histological types of high-grade endometrial carcinomas but a significant outcome association is only seen in grade 3 endometrioid carcinoma, suggesting a greater biological importance in this tumor type.

POLE exonuclease domain mutation predicts long progression-free survival in grade 3 endometrioid carcinoma of the endometrium.

OBJECTIVE: POLE exonuclease domain mutations were recently found to occur in a subset of endometrial carcinomas and result in defective proof-reading function during DNA replication. The aim of this study is to further characterize the clinical and pathologic significance of POLE exonuclease domain mutations in high-grade endometrial carcinomas. METHODS: We assessed for mutations in the exonuclease domain of POLE by Sanger sequencing in 53 grade 3 endometrioid, 25 serous, 16 clear cell and 5 dedifferentiated carcinomas. We correlated POLE mutation status with clinicopathologic features and molecular parameters. Univariate and multivariate survival analyses were performed using Kaplan-Meier and cox regression analyses. RESULTS: POLE exonuclease domain mutations were identified in 8 of 53 (15%) grade 3 endometrioid carcinomas and not in any other histotypes examined. Only 1 of the 8 grade 3 endometrioid carcinomas with POLE exonuclease domain mutation displayed deficient mismatch repair protein expression by immunohistochemistry (MSH6 loss), compared to 21 of 45 grade 3 endometrioid carcinomas with wild-type exonuclease domain. When analyzed together with published grade 3 endometrioid carcinomas by The Cancer Genome Atlas, the presence of POLE exonuclease domain mutation was associated with significantly better progression-free survival in univariate (p=0.025) and multivariate (p=0.010) analyses, such that none of the patients with POLE mutated tumors experienced disease progression CONCLUSIONS: POLE exonuclease domain mutations occur in a subset of grade 3 endometrioid carcinomas and are associated with good clinical outcome. It can serve as an important prognostic molecular marker to guide the management of patients with grade 3 endometrioid carcinomas.

Mesonephric-type adenocarcinomas of the ovary: prevalence, diagnostic reproducibility, outcome, and value of PAX2.

Mesonephric-type (or -like) adenocarcinomas (MAs) of the ovary are an uncommon and aggressive histotype. They appear to arise through transdifferentiation from Müllerian lesions creating diagnostic challenges. Thus, we aimed to develop a histologic and immunohistochemical (IHC) approach to optimize the identification of MA over its histologic mimics, such as ovarian endometrioid carcinoma (EC). First, we screened 1,537 ovarian epithelial neoplasms with a four-marker IHC panel of GATA3, TTF1, ER, and PR followed by a morphological review of EC to identify MA in retrospective cohorts. Interobserver reproducibility for the distinction of MA versus EC was assessed in 66 cases initially without and subsequently with IHC information (four-marker panel). Expression of PAX2, CD10, and calretinin was evaluated separately, and survival analyses were performed. We identified 23 MAs from which 22 were among 385 cases initially reported as EC (5.7%) and 1 as clear cell carcinoma. The interobserver reproducibility increased from fair to substantial (κ = 0.376-0.727) with the integration of the four-marker IHC panel. PAX2 was the single most sensitive and specific marker to distinguish MA from EC and could be used as a first-line marker together with ER/PR and GATA3/TTF1. Patients with MA had significantly increased risk of earlier death from disease (hazard ratio = 3.08; 95% CI, 1.62-5.85; p < 0.0001) compared with patients with EC, when adjusted for age, stage, and p53 status. A diagnosis of MA has prognostic implications for stage I disease, and due to the subtlety of morphological features in some tumors, a low threshold for ancillary testing is recommended.

Concurrent RB1 Loss and BRCA-Deficiency Predicts Enhanced Immunological Response and Long-Term Survival in Tubo-Ovarian High-Grade Serous Carcinoma.

PURPOSE: To evaluate RB1 expression and survival across ovarian carcinoma histotypes, and how co-occurrence of BRCA1 or BRCA2 (BRCA) alterations and RB1 loss influences survival in tubo-ovarian high-grade serous carcinoma (HGSC). EXPERIMENTAL DESIGN: RB1 protein expression was classified by immunohistochemistry in ovarian carcinomas of 7436 patients from the Ovarian Tumor Tissue Analysis consortium. We examined RB1 expression and germline BRCA status in a subset of 1134 HGSC, and related genotype to overall survival (OS), tumor-infiltrating CD8+ lymphocytes and transcriptomic subtypes. Using CRISPR-Cas9, we deleted RB1 in HGSC cells with and without BRCA1 alterations to model co-loss with treatment response. We performed whole-genome and transcriptome data analyses on 126 primary HGSC to characterize tumors with concurrent BRCA-deficiency and RB1 loss. RESULTS: RB1 loss was associated with longer OS in HGSC, but with poorer prognosis in endometrioid ovarian carcinoma. Patients with HGSC harboring both RB1 loss and pathogenic germline BRCA variants had superior OS compared to patients with either alteration alone, and their median OS was three times longer than those without pathogenic BRCA variants and retained RB1 expression (9.3 vs. 3.1 years). Enhanced sensitivity to cisplatin and paclitaxel was seen in BRCA1-altered cells with RB1 knockout. Combined RB1 loss and BRCA-deficiency correlated with transcriptional markers of enhanced interferon response, cell-cycle deregulation, and reduced epithelial-mesenchymal transition. CD8+ lymphocytes were most prevalent in BRCA-deficient HGSC with co-loss of RB1. CONCLUSIONS: Co-occurrence of RB1 loss and BRCA-deficiency was associated with exceptionally long survival in patients with HGSC, potentially due to better treatment response and immune stimulation.

The diagnostic utility of TP53 and CDKN2A to distinguish ovarian high-grade serous carcinoma from low-grade serous ovarian tumors.

Low-grade serous carcinomas and serous borderline tumors, combined herein and referred to as low-grade serous tumors, show distinct molecular alterations and clinical behaviors compared with high-grade serous carcinomas. The discrimination between low-grade serous tumors and high-grade serous carcinomas can be challenging on small tissue samples, such as cell blocks of paracentesis fluid or biopsies from omental disease. The purpose of this study was to test the ability of TP53 and CDKN2A immunohistochemistry to distinguish between high-grade serous carcinomas and low-grade serous tumors on small tissue samples. Tissue microarrays containing 582 high-grade serous carcinomas, 45 low-grade serous carcinomas, and 49 serous borderline tumors, confirmed by contemporary histopathological review, were stained for TP53 and CDKN2A (DO7 and E6H4 antibody clones, respectively). TP53 was scored as completely absent, wild-type pattern or overexpressed (>60%), and CDKN2A was scored as either negative/patchy (<90%) or block expression (>90%). The combination of the two markers, ie, the TP53 wild-type pattern and CDKN2A patchy expression, had sensitivity for low-grade serous tumors of 89%, a specificity of 93%, a positive predictive value of 68%, and a negative predictive value of 98%. These markers can, therefore, be used on small biopsies/cell blocks to refute a diagnosis of low-grade serous tumors. These findings may inform emerging neoadjuvant therapeutic strategies in advanced ovarian cancers and may be crucial for future clinical trials on molecular-based therapies.

Quantification of ER/PR expression in ovarian low-grade serous carcinoma.

OBJECTIVE: Case reports suggest that hormonal therapy may be a useful treatment option for low-grade serous carcinomas (LGSC) but the clinical value remains uncertain. We hypothesized that LGSCs show a constitutive high hormone receptor expression and that type diagnosis may be sufficient to initiate hormonal therapy. METHODS: We assessed ER and PR expression on 27 LGSC, 69 high-grade serous carcinomas (HGSC), 36 serous borderline tumors (SBOT), and five normal fallopian tubes using three different platforms/antibodies on tissue microarrays. Staining from the Leica Bond Max and DAKO PharmDx platforms was evaluated using the Allred score. Quantitative fluorescence immunohistochemistry was performed using the HistoRx AQUAnalysis platform. A second cohort of 12 LGSC and 183 HGSC was assessed using the HistoRx AQUAnalysis platform. Welch ANOVA or Fisher's Exact Test was used to compare differences in the histological types for each platform. Nonparametric bivariate density plots were used to graphically demonstrate the relationship between ER and PR for the various histological types. RESULTS: LGSC have higher ER and PR expression compared to HGSC but significantly less than FT and SBOT. Nonparametric bivariate density revealed two populations of LGSC: one fifth of LGSC are ER high/PR high expressers similar to SBOT but the majority show low ER/PR expression more like HGSC. CONCLUSIONS: Quantitative assessment of ER/PR expression using the HistoRx AQUAnalysis platform may be useful as a predictive diagnostic for hormonal therapy in LGSC, assuming that only the fraction of double high expressers benefit from hormonal treatment.

MMR deficiency is common in high-grade endometrioid carcinomas and is associated with an unfavorable outcome.

OBJECTIVE: To assess the prevalence of MMR deficiency (dMMR) in contemporary reclassified high-grade endometrial carcinomas and correlate dMMR with molecular alterations and patient outcome. METHODS: In this study we evaluated the expression of MLH1, MSH2, PMS2 and MSH6 assessed by two different methods in a series of 102 high-grade endometrial carcinomas. The series was comprised of 64 high-grade endometrioid carcinomas (HGEC), 27 serous (ESC), and 11 clear cell (CCC) carcinomas. Absence of expression in any of the proteins was considered dMMR. dMMR was correlated with clinicopathological parameters using a Chi-square test. Univariate and multivariate survival analysis was performed using Kaplan-Meier and Cox regression analyses. RESULTS: The overall prevalence of dMMR was 28% (29/102) and was seen in 29/64 (45%) HGEC but not detected in any of the ESC and CCC. Within HGEC, dMMR was associated with loss of ARID1A (p=0.0099), loss of PTEN (p=0.044) and wild-type TP53 (p=0.024) expression. dMMR was associated with increased risk for disease specific death by univariate analysis (p=0.013) among stage III/IV HGEC but not in multivariate analysis (p=0.12). CONCLUSIONS: Among high-grade endometrial carcinomas, dMMR is restricted to HGEC and could be used as an adjunct diagnostic tool to refute a diagnosis of ESC. The association with dMMR in HGEC with ARID1A/PTEN alterations, TP53 wild type expression pattern and unfavorable outcome suggests that different oncogenetic pathways within HGEC are present.

p53 and ovarian carcinoma survival: an Ovarian Tumor Tissue Analysis consortium study.

Our objective was to test whether p53 expression status is associated with survival for women diagnosed with the most common ovarian carcinoma histotypes (high-grade serous carcinoma [HGSC], endometrioid carcinoma [EC], and clear cell carcinoma [CCC]) using a large multi-institutional cohort from the Ovarian Tumor Tissue Analysis (OTTA) consortium. p53 expression was assessed on 6,678 cases represented on tissue microarrays from 25 participating OTTA study sites using a previously validated immunohistochemical (IHC) assay as a surrogate for the presence and functional effect of TP53 mutations. Three abnormal expression patterns (overexpression, complete absence, and cytoplasmic) and the normal (wild type) pattern were recorded. Survival analyses were performed by histotype. The frequency of abnormal p53 expression was 93.4% (4,630/4,957) in HGSC compared to 11.9% (116/973) in EC and 11.5% (86/748) in CCC. In HGSC, there were no differences in overall survival across the abnormal p53 expression patterns. However, in EC and CCC, abnormal p53 expression was associated with an increased risk of death for women diagnosed with EC in multivariate analysis compared to normal p53 as the reference (hazard ratio [HR] = 2.18, 95% confidence interval [CI] 1.36-3.47, p = 0.0011) and with CCC (HR = 1.57, 95% CI 1.11-2.22, p = 0.012). Abnormal p53 was also associated with shorter overall survival in The International Federation of Gynecology and Obstetrics stage I/II EC and CCC. Our study provides further evidence that functional groups of TP53 mutations assessed by abnormal surrogate p53 IHC patterns are not associated with survival in HGSC. In contrast, we validate that abnormal p53 IHC is a strong independent prognostic marker for EC and demonstrate for the first time an independent prognostic association of abnormal p53 IHC with overall survival in patients with CCC.

Concurrent RB1 loss and BRCA-deficiency predicts enhanced immunological response and long-term survival in tubo-ovarian high-grade serous carcinoma.

Background: Somatic loss of the tumour suppressor RB1 is a common event in tubo-ovarian high-grade serous carcinoma (HGSC), which frequently co-occurs with alterations in homologous recombination DNA repair genes including BRCA1 and BRCA2 (BRCA). We examined whether tumour expression of RB1 was associated with survival across ovarian cancer histotypes (HGSC, endometrioid (ENOC), clear cell (CCOC), mucinous (MOC), low-grade serous carcinoma (LGSC)), and how co-occurrence of germline BRCA pathogenic variants and RB1 loss influences long-term survival in a large series of HGSC. Patients and methods: RB1 protein expression patterns were classified by immunohistochemistry in epithelial ovarian carcinomas of 7436 patients from 20 studies participating in the Ovarian Tumor Tissue Analysis consortium and assessed for associations with overall survival (OS), accounting for patient age at diagnosis and FIGO stage. We examined RB1 expression and germline BRCA status in a subset of 1134 HGSC, and related genotype to survival, tumour infiltrating CD8+ lymphocyte counts and transcriptomic subtypes. Using CRISPR-Cas9, we deleted RB1 in HGSC cell lines with and without BRCA1 mutations to model co-loss with treatment response. We also performed genomic analyses on 126 primary HGSC to explore the molecular characteristics of concurrent homologous recombination deficiency and RB1 loss. Results: RB1 protein loss was most frequent in HGSC (16.4%) and was highly correlated with RB1 mRNA expression. RB1 loss was associated with longer OS in HGSC (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.66-0.83, P = 6.8 ×10-7), but with poorer prognosis in ENOC (HR 2.17, 95% CI 1.17-4.03, P = 0.0140). Germline BRCA mutations and RB1 loss co-occurred in HGSC (P < 0.0001). Patients with both RB1 loss and germline BRCA mutations had a superior OS (HR 0.38, 95% CI 0.25-0.58, P = 5.2 ×10-6) compared to patients with either alteration alone, and their median OS was three times longer than non-carriers whose tumours retained RB1 expression (9.3 years vs. 3.1 years). Enhanced sensitivity to cisplatin (P < 0.01) and paclitaxel (P < 0.05) was seen in BRCA1 mutated cell lines with RB1 knockout. Among 126 patients with whole-genome and transcriptome sequence data, combined RB1 loss and genomic evidence of homologous recombination deficiency was correlated with transcriptional markers of enhanced interferon response, cell cycle deregulation, and reduced epithelial-mesenchymal transition in primary HGSC. CD8+ lymphocytes were most prevalent in BRCA-deficient HGSC with co-loss of RB1. Conclusions: Co-occurrence of RB1 loss and BRCA mutation was associated with exceptionally long survival in patients with HGSC, potentially due to better treatment response and immune stimulation.