CHEK1 and osteosarcoma: Other common genetic mutations associated with the HR repair pathway were also observed in these two osteosarcoma cell lines (Supplementary Tables 1 and 2): BRIP1, CHEK1, FANCD2, FANCI, FANCM, NBN, and RAD51D (U2OS cells); ATM, ATR, BLM, BRIP1, FANCA, FANCI, FANCL, FANCM, NBN, RAD51C, and RPA1 (K7M2 cells).