BRCA1 and breast cancer: Subgroup analyses revealed a larger proportion of BRCA1 mutations in TNBC than non-TNBC among patients 1) diagnosed at early-age with no family history of breast/ovarian cancer (14 % vs. 5 %, P = 0.03), 2) diagnosed at early-age irrespective of family history (28 % vs. 11 %, P = 0.0003), 3) had a family history of breast cancer (49 % vs. 12 %, P < 0.0001), and 4) those with family history of breast and ovarian cancer (81 % vs. 28 %, P = 0.0005).