CHEK2 and breast cancer: Of these, 3.54% of cases (n = 35/990) and 0.37% of controls (n = 4/1,094), harbored PTVs in the established breast cancer susceptibility genes ATM, BARD1, BRCA1, BRCA2, CHEK2, PALB2, RAD51C, RAD51D and TP53 (Dorling et al., 2021).