Flanagan et al. performed methylation microarray analyses of peripheral blood DNA across genes including BRCA1, BRCA2, CHEK2, ATM, TP53, CDH1 and MLH1 and demonstrated gene body hypermethylation of ATM was associated with a 3-fold increase risk of breast cancer (P = 0.0017) [7]. Here, CHEK2 is linked to breast cancer.