Considering the breast cancer only index cases, there were 33 PALB2 PGVs and 43 CHEK2_c.1100delC PGVs (PALB2: OR = 6.16, 95% CI = 1.98–19.21, P = 0.0003; CHEK2: OR = 4.83, 95% CI = 2.01–11.34, P = 0.0001). This evidence concerns the gene CHEK2 and breast cancer.