BRCA1 and breast cancer: In a recent study the average cumulative risks by age 70 years for BRCA1 carriers were estimated to be 60 % (95 % confidence interval [CI] = 44 to 75 %) for BC, 59 % (95 % CI = 43 to 76 %) for OC, and 83 % (95 % CI = 69 to 94 %) for contralateral BC [8].