ATM and breast cancer: CHEK2 has a role in DNA repair, although at an earlier stage whereby it detects then determines the cellular response to DNA damage.29 We detected the CHEK2_1100delC PGV in 44/3,127 cases compared with just 5/1,567 controls reflecting the also increased OR attained from the much larger BRIDGES study.20 There has been considerable debate regarding the utility of including the moderate risk penetrance genes, CHEK2 and ATM, in breast cancer diagnostic genetic testing panels.