BRCA1 and breast cancer: Breast cancer risks for carriers of 6174delT were lower than those of all BRCA1 carriers (43% by age 70, 95% CI, 14% to 62%; p = 0.007 compared with all BRCA1 mutation carriers), on the other hand, the ovarian cancer risks in the carriers were somewhat higher than the average BRCA2 risks (20% vs. 11%) [63].