Association of BRCA1 and BRCA2 Mutations With Survival, Chemotherapy Sensitivity, and Gene Mutator Phenotype in Patients With Ovarian Cancer

To determine the relationships between BRCA1/2 deficiency (ie, mutation and promoter hypermethylation) and overall survival (OS), progression-free survival (PFS), chemotherapy response, and whole-exome mutation rate in ovarian cancer. DESIGN, SETTING, AND PATIENTS: Observational study of multidimensional genomics and clinical data on 316 high-grade serous ovarian cancer cases that were made public between 2009 and 2010 via The Cancer Genome Atlas project. MAIN OUTCOME MEASURES: OS and PFS rates (primary outcomes) and chemotherapy response (secondary outcome).

BRCA2 mutations (29 cases) were associated with significantly better OS (adjusted hazard ratio [HR], 0.33; 95% CI, 0.16-0.69; P = .003 and 5-year OS, 61% for BRCA2-mutated vs 25% for BRCA wild-type cases) and PFS (adjusted HR, 0.40; 95% CI, 0.22-0.74; P = .004 and 3-year PFS, 44% for BRCA2-mutated vs 16% for BRCA wild-type cases), whereas neither BRCA1 mutations (37 cases) nor BRCA1 methylation (33 cases) was associated with prognosis. Moreover, BRCA2 mutations were associated with a significantly higher primary chemotherapy sensitivity rate (100% for BRCA2-mutated vs 82% [P = .02] and 80% [P = .05] for BRCA wild-type and BRCA1-mutated cases, respectively) and longer platinum-free duration (median platinum-free duration, 18.0 months for BRCA2-mutated vs 11.7 [P = .02] and 12.5 [P = .04] months for BRCA wild-type and BRCA1-mutated cases, respectively). BRCA2-mutated, but not BRCA1-mutated cases, exhibited a "mutator phenotype" by containing significantly more mutations than BRCA wild-type cases across the whole exome (median mutation number per sample, 84 for BRCA2-mutated vs 52 for BRCA wild-type cases, false discovery rate