BRCA1 and ovarian cancer: Approximately 15% to 20% of patients with ovarian cancer are BRCA1 or BRCA2 mutation carriers.9 These mutations increase a woman's lifetime risk of ovarian cancer up to 40% for BRCA1 carriers and up to 20% for BRCA2 carriers.9,10 Estimates of the lifetime risk of breast cancer for BRCA1/2 mutation carriers range from 41% to 90%.