It is estimated that around 5% of breast cancer cases harbor PVs in established breast cancer susceptibility genes (ATM, BARD1, BRCA1, BRCA2, CHEK2, PALB2, RAD51C, RAD51D, TP53), of which the most prevalent occur in BRCA2, CHEK2 and BRCA1 (Dorling et al., 2021; Hu et al., 2021). This evidence concerns the gene CHEK2 and breast cancer.