Among these variants, we identified 55 pathogenic variants in established breast cancer genes including ATM, BRCA1, BRCA2, CDH1, CHEK2, NBN, NF1, PALB2, PTEN, and TP53 and 5 pathogenic variants in candidate breast cancer genes including BARD1, BRIP1, and RAD51D (Supplementary Table S1), including 31 frameshift indels, 18 nonsense variants, 6 missense variants, 2 splicing variants, and 3 large deletions (Fig. 1). Here, CHEK2 is linked to breast cancer.