Among women with ER-negative BC, BRCA1 PVs were dominant, ranging from 74.6% in the PPBC at 5 to less than 10 years group to 87.3% in the PPBC at less than 5 years group; the frequency distribution of BRCA1 among the nulliparous group was 81.1% and among the parous BC at 10 years or more group was 80% (P = .08). Here, BRCA1 is linked to breast cancer.