BRCA2 and breast cancer: For BRCA2 carriers, the corresponding risks were 55 % (95 % CI = 41 to 70 %) for BC, 16.5 % (95 % CI = 7.5 to 34 %) for OC, and 62 % (95 % CI = 44 % to 79.5 %) for contralateral BC [8].