ATM and breast cancer: However, other BC susceptibility genes have recently been identified, including moderate-penetrance genes (such as ATM, BARD1, CHEK2, RAD51C, and RAD51D), as well as other genes already known for their role in rare cancer predisposition syndromes (CPS), which also include BC susceptibility (such as CDH1, PTEN, STK11, and TP53) [3,4].