The age-standardized incidence rate of breast cancer diagnosis was estimated to be 26.94 per 1,000 per year in BRCA1 carriers (95% confidence interval (CI) = 19.79, 34.10) compared with 25.03 per 1,000 per year in BRCA2 carriers (95% CI = 18.71, 31.36). Here, BRCA1 is linked to breast cancer.