Brenton, James D.

AbstractWe aimed to validate the prognostic association of p16 expression in ovarian high‐grade serous carcinomas (HGSC) and to explore it in other ovarian carcinoma histotypes. p16 protein expression was assessed by clinical‐grade immunohistochemistry in 6525 ovarian carcinomas including 4334 HGSC using tissue microarrays from 24 studies participating in the Ovarian Tumor Tissue Analysis consortium. p16 expression patterns were interpreted as abnormal (either overexpression referred to as block expression or absence) or normal (heterogeneous). CDKN2A (which encodes p16) mRNA expression was also analyzed in a subset (n = 2280) mostly representing HGSC (n = 2010). Association of p16 expression with overall survival (OS) was determined within histotypes as was CDKN2A expression for HGSC only. p16 block expression was most frequent in HGSC (56%) but neither protein nor mRNA expression was associated with OS. However, relative to heterogeneous expression, block expression was associated with shorter OS in endometriosis‐associated carcinomas, clear cell [hazard ratio (HR): 2.02, 95% confidence (CI) 1.47–2.77, p < 0.001] and endometrioid (HR: 1.88, 95% CI 1.30–2.75, p = 0.004), while absence was associated with shorter OS in low‐grade serous carcinomas (HR: 2.95, 95% CI 1.61–5.38, p = 0.001). Absence was most frequent in mucinous carcinoma (50%), and was not associated with OS in this histotype. The prognostic value of p16 expression is histotype‐specific and pattern dependent. We provide definitive evidence against an association of p16 expression with survival in ovarian HGSC as previously suggested. Block expression of p16 in clear cell and endometrioid carcinoma should be further validated as a prognostic marker, and absence in low‐grade serous carcinoma justifies CDK4 inhibition.

Abstract Large-scale genome-wide association studies (GWAS) have identified approximately 35 loci associated with epithelial ovarian cancer (EOC) risk. The majority of GWAS-identified disease susceptibility variants are located in noncoding regions, and causal genes underlying these associations remain largely unknown. Here, we performed a transcriptome-wide association study to search for novel genetic loci and plausible causal genes at known GWAS loci. We used RNA sequencing data (68 normal ovarian tissue samples from 68 individuals and 6,124 cross-tissue samples from 369 individuals) and high-density genotyping data from European descendants of the Genotype-Tissue Expression (GTEx V6) project to build ovarian and cross-tissue models of genetically regulated expression using elastic net methods. We evaluated 17,121 genes for their cis-predicted gene expression in relation to EOC risk using summary statistics data from GWAS of 97,898 women, including 29,396 EOC cases. With a Bonferroni-corrected significance level of P &lt; 2.2 × 10−6, we identified 35 genes, including FZD4 at 11q14.2 (Z = 5.08, P = 3.83 × 10−7, the cross-tissue model; 1 Mb away from any GWAS-identified EOC risk variant), a potential novel locus for EOC risk. All other 34 significantly associated genes were located within 1 Mb of known GWAS-identified loci, including 23 genes at 6 loci not previously linked to EOC risk. Upon conditioning on nearby known EOC GWAS-identified variants, the associations for 31 genes disappeared and three genes remained (P &lt; 1.47 × 10−3). These data identify one novel locus (FZD4) and 34 genes at 13 known EOC risk loci associated with EOC risk, providing new insights into EOC carcinogenesis. Significance: Transcriptomic analysis of a large cohort confirms earlier GWAS loci and reveals FZD4 as a novel locus associated with EOC risk. Cancer Res; 78(18); 5419–30. ©2018 AACR.

Abstract Germline and somatic mutations in BRCA1 and BRCA2 (BRCA) confer PARP inhibitor sensitivity. Promoter hypermethylation is an alternate mechanism of gene down-regulation, and BRCA1 promoter methylation is relatively common in sporadic ovarian cancer. The clinical significance of BRCA1 methylation is less clear than for mutations, as the Cancer Genome Atlas (TCGA) and others have failed to show improved survival in ovarian carcinomas with BRCA1 methylation. No one has previously tested whether BRCA1 methylation confers in vivo sensitivity to PARP inhibitors in patients with ovarian cancer. ARIEL2 is a phase 2 study of the PARP inhibitor rucaparib in patients with recurrent platinum sensitive high-grade ovarian, peritoneal or fallopian tube carcinoma. At enrollment, ARIEL2 required pre-treatment tumor biopsies with the goal of developing tissue predictors of PARP inhibitor sensitivity other than BRCA mutations. The number of women with known germline mutations was capped at 15 patients in order to predominantly enroll BRCA wildtype cases. As presented at ASCO 2016, in cases with no BRCA mutations, a high fraction of genomic loss of heterozygosity (LOH) significantly predicted a better progression-free survival (the primary endpoint), longer duration of response, and a higher fraction of responders compared to cases with low LOH. We assessed BRCA1 and RAD51C promoter hypermethylation using methylation-sensitive polymerase chain reaction in paired archival and pre-treatment biopsies from patients on ARIEL2. Of 165 cases for which methylation analyses were completed, 21 (12.7%) were methylated at the BRCA1 promoter and four (2.4%) at the RAD51C promoter. Methylation of BRCA1 and RAD51C was mutually exclusive with mutation in BRCA or other homologous recombination genes. All four cases with RAD51C methylation and 15/19 (78.9%) with BRCA1 methylation were associated with high LOH. In 90 paired samples archival and pre-treatment tissues, RAD51C methylation was 100% concordant and BRCA1 methylation was highly concordant (p&lt;0·001). For 13 cases with BRCA1 methylation in the archival specimen, 4 (30·8%) were unmethylated in the paired pretreatment tumor, but for 77 unmethylated archival specimens, gain of methylation in the pretreatment biopsy was observed just once. Confirmed RECIST responses were seen in 52.4% (11/21) BRCA1 methylated and 75.0% (3/4) RAD51C methylated cases. In conclusion, BRCA1 and RAD51C methylation in ovarian carcinomas correlates with a high response rate to PARP inhibitors. If methylation was to be used as a predictor of PARP inhibitor sensitivity, it would need to be assessed in a pre-treatment (not archival) specimen. The loss of BRCA1 methylation in recurrent ovarian carcinoma, which was common even in these platinum sensitive cases, could explain why BRCA1 methylation is associated with similar survival to methylated cases, despite initial improved therapeutic sensitivity. Citation Format: Elizabeth Swisher, Maria Harrell, Kevin K. Lin, Clare Scott, Sandra Goble, Amit Oza, Robert L. Coleman, Gottfried Konecny, Anna V. Tinker, David M. O'Malley, Rebecca Kristeleit, Ling Ma, James Brenton, Katherine Bell-McGuinn, Ana Oaknin, Alexandra Leary, Elaina Mann, Heidi Giordano, Mitch Rapon, Iain McNeish, Scott H. Kaufmann. BRCA1 and RAD51C Promoter Hypermethylation Confer Sensitivity to PARP Inhibitors in Patients with Platinum Sensitive Ovarian Carcinoma [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr AP28.

Abstract Background: PARP inhibitors are thought to be effective therapy for cancers with homologous recombination (HR) deficiency, best shown to date in patients (pts) with a germline BRCA (gBRCA) mutation. The Cancer Genome Atlas (TCGA) estimated ∼ 50% of high-grade serous ovarian carcinoma (OC) pts have an HR defect (HRD) due to a BRCA mutation (germline or somatic), other HR gene mutation, or another mechanism, e.g., BRCA1 promoter methylation. A randomized maintenance trial of olaparib in recurrent OC demonstrated a clinical benefit in both gBRCA-mutated and gBRCA-wild-type pts. Currently, the best molecular predictors of PARPi response (other than a BRCA mutation) are not known. Platinum sensitivity, often used as a surrogate predictive indicator for PARPi response, is inadequate. A better technique, such as molecular analysis of tumor tissue, could be a superior method for selection of pts for PARPi therapy. Methods: The rucaparib development plan in OC employs a unique strategy of conducting the key trials in parallel, allowing the Phase 2 (ARIEL2) to complete first so that a molecular HRD signature, associated with sub-groups most likely to benefit, can be prospectively applied to the final analysis of the Phase 3 pivotal trial (ARIEL3). ARIEL2 is an ongoing, single-arm, open-label biomarker study designed to refine the molecular signature associated with a response to rucaparib. Eligible pts (n=180) have relapsed, platinum-sensitive, high-grade OC and measurable disease. All pts undergo a pre-dose biopsy and provide archival tumor tissue. Tumor tissue HR status is assessed using Foundation Medicine's next generation sequencing (NGS) platform and University of Washington's BROCA-HR panel, with the current HRD algorithm developed using in vitro/in vivo and TCGA (and similar) bioinformatic data. The key efficacy analyses to be correlated with tumor HR status are response by RECIST v1.1, GCIG-defined CA-125 response, and PFS. The number of gBRCA pts is limited to maximize non-gBRCA response predictors. Exploratory biomarkers include assessment of tissue NHEJ competency (candidate predictive biomarker) and circulating tumor DNA (candidate efficacy surrogate). The optimized algorithm will then be tested prospectively in ARIEL3 (n=540), an international, randomized (2:1), double-blind, placebo-controlled maintenance trial in platinum-sensitive OC in remission after platinum-based therapy. The primary endpoint of ARIEL3 is PFS in molecularly-defined HRD subgroups as determined by NGS analysis of archival tumor tissue using the optimized algorithm, refined (as required) through ARIEL2.Conclusion: This pair of clinical trials seeks to determine prospectively the appropriate population, among all women with platinum-sensitive OC, who derive a meaningful benefit from PARPi treatment in the maintenance setting. Citation Format: Elizabeth Swisher, Iain McNeish, Robert L. Coleman, James D. Brenton, Scott H. Kaufmann, Andrew Allen, Mitch Raponi, Heidi Giordano, Lara Maloney, Jeffrey Isaacson, Jonathan A. Ledermann. Prospective molecular identification of ovarian cancer patients benefiting from PARP inhibitor (PARPi, rucaparib) maintenance therapy - reaching beyond germline BRCA mutations. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT339. doi:10.1158/1538-7445.AM2014-CT339

Abstract Purpose: To analyze the effect of germline mutations in BRCA1 and BRCA2 on mortality in patients with ovarian cancer up to 10 years after diagnosis. Experimental Design: We used unpublished survival time data for 2,242 patients from two case–control studies and extended survival time data for 4,314 patients from previously reported studies. All participants had been screened for deleterious germline mutations in BRCA1 and BRCA2. Survival time was analyzed for the combined data using Cox proportional hazard models with BRCA1 and BRCA2 as time-varying covariates. Competing risks were analyzed using Fine and Gray model. Results: The combined 10-year overall survival rate was 30% [95% confidence interval (CI), 28%–31%] for non-carriers, 25% (95% CI, 22%–28%) for BRCA1 carriers, and 35% (95% CI, 30%–41%) for BRCA2 carriers. The HR for BRCA1 was 0.53 at time zero and increased over time becoming greater than one at 4.8 years. For BRCA2, the HR was 0.42 at time zero and increased over time (predicted to become greater than 1 at 10.5 years). The results were similar when restricted to 3,202 patients with high-grade serous tumors and to ovarian cancer–specific mortality. Conclusions: BRCA1/2 mutations are associated with better short-term survival, but this advantage decreases over time and in BRCA1 carriers is eventually reversed. This may have important implications for therapy of both primary and relapsed disease and for analysis of long-term survival in clinical trials of new agents, particularly those that are effective in BRCA1/2 mutation carriers. Clin Cancer Res; 21(3); 652–7. ©2014 AACR.

Abstract Our understanding of ovarian cancer is complicated by disease heterogeneity. There are five major histological types, each with alterations in different pathways and distinct clinical outcomes. Even within these histological types there is clinical and molecular heterogeneity. The Ovarian Tumor Tissue Analysis (OTTA) consortium was established to validate prognostic markers for ovarian cancer in a large population of patients to allow stratification by histological type and molecular subtype. OTTA is currently a collaboration among 38 studies and has tissue microarrays (TMAs) from over 8,000 tumors available for immunohistochemical (IHC) analysis. In addition formalin fixed paraffin embedded (FFPE) tissue on slides or cores are available from the majority of OTTA studies for DNA and RNA analysis. Approximatley 60% of the cases are part of the Ovarian Cancer Association Consortium (OCAC) and have genotype data on over 200,000 single nucleotide polymorphisms and extensive epidemiological data. We recently performed IHC analysis of 12 markers using centralised staining and scoring to reduce heterogeneity and improve power to validate biomarkers. We showed that estrogen receptor and progesterone receptor were prognostic markers for endometrioid and high-grade serous carcinomas by performing the first robust subtype-specific analyses of these biomarkers in nearly 3000 patients. In contrast, FOLR1 expression was not associated with survival in 1507 high-grade serous carcinomas. We have shown that FFPE material from OTTA is suitable for RNA expression analysis on high through-put platforms such as the NanoString GX system. Expression analysis of 50 candidate genes in 244 high grade serous ovarian cancer cases has validated prognostic markers identified by The Cancer Genome Atlas (TCGA) project and investigated a series of novel candidate genes. IHC and RNA expression profiling from formalin fixed paraffin embedded (FFPE) tumor tissue is being used to better subclassify the ovarian tumors for further analysis. We would welcome groups with collections of ovarian tumor samples and corrsponding clinical data to join OTTA and participate in ongoing collaborative projects. Citation Format: Susan J. Ramus, Martin Köbel, Weiva Sieh, Michael S. Anglesio, Joshua Millstein, David D. Bowtell, James D. Brenton, Estrid Høgdall, Paul DP Pharoah, Ellen L. Goode, David G. Huntsman. The ovarian tumor tissue analysis (OTTA) consortium. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A27.