In two previous studies of our group, we screened young BC women (Carraro et al., 2013) and women with clinical criteria of HBOC (Silva et al., 2014) for pathogenic variants in the complete coding sequence of BRCA1, BRCA2, and TP53 genes, and for CHEK2 c.1100delC point mutation, detecting 22–26% of pathogenic variant carriers. Here, CHEK2 is linked to breast cancer.