In the multivariate logistic regression analysis, age at diagnosis (OR, 0.95; 95% CI, 0.94–0.97; P < 0.001), Ki67 index (OR, 1.01; 95% CI, 1.00–1.02; P = 0.009), TNBC (OR, 2.88; 95% CI 1.88–4.39; P < 0.001), history of contralateral breast cancer (OR, 3.01; 95% CI, 1.04–7.57; P = 0.03), and family history of cancer (OR, 1.53; 95% CI, 1.05–2.21; P = 0.025) were the most useful predictors of germline mutations in BCDG (Supplementary Table S9). Here, MKI67 is linked to breast cancer.