CHEK2 and breast carcinoma: Breast cancer was most frequent among individuals with 2 PVs in CHEK2 (100%) followed by those with PV and LR variant (86.7%), a monoallelic PV (67.1%), 2 LR variants (60.0%), a monoallelic LR variant (57.5%), and WT (52.7%) (Figure 2; Table).