CHEK2 and cancer: To obtain population prevalence and more precise risk estimations for the recurrent moderate-to-high risk breast cancer susceptibility alleles, here we genotyped 2343 Northern Finnish unselected breast cancer cases and 4607 cancer-free controls for 16 pathogenic/likely pathogenic variants in BRCA1, BRCA2, PALB2, ATM, CHEK2, FANCM, MCPH1 and RAD50 DDR genes, which have previously been associated with breast cancer susceptibility in the Finnish population [9, 10, 14, 16, 24–26] or reported as recurrent in breast cancer families in the clinics [27].