CHEK2 and breast cancer: Female carriers of pathogenic variants (PVs) in high and moderate penetrance susceptibility genes, such as BRCA1 DNA repair-associated gene (BRCA1), BRCA2 DNA repair-associated gene (BRCA2), tumor protein p53 gene (TP53), partner and localizer of BRCA2 gene (PALB2), checkpoint kinase 2 gene (CHEK2), and ATM serine/threonine kinase gene (ATM), are at a highly increased risk of developing BC and OC compared with women in the general population [3,4].