CHEK2 and Hereditary breast and ovarian cancer syndrome: A mutation not only in BRCA1/2 but also in several other genes, including TP53, PTEN, and CDH1 (with high penetrance), and ATM, CHEK2, and PALB2 (with moderate penetrance), can lead to hereditary breast and ovarian cancer (HBOC) syndrome, which has been linked with different levels of risk and prevalence in the population1,2.