CHEK2 and Hereditary breast and ovarian cancer syndrome: Genetic factors include hereditary mutations in high penetrance genes, such as BRCA1 or 2, resulting in hereditary breast and ovarian cancer (HBOC), while other predisposition genes such as PALB2, CDH, PTEN, ATM, STK11, CHEK2, and TP53 have lower penetrance [15].