The NCCN guideline list the susceptibility genes of hereditary breast cancer, including 6 high penetrance (BRCA1, BRCA2, CDH1, PALB2, PTEN and TP53) and 9 moderate to low penetrance (ATM, BARD1, BRIP1, CHEK2, NBN, NF1, RAD51C, RAD51D and STK11) susceptibility genes, most of which also participate in HRR pathway (Nielsen et al., 2016). Here, CHEK2 is linked to Hereditary breast cancer.