CHEK1 and neoplasm: Any tumor having a defect in the homologous recombination function would show synthetic lethality with PARP, which subsequently displays several gene mutations, including BRAC1, BRAC2, ATM, RAD51, RAD54, XRCC2, XRCC3, DSS1, RPA1, CHK1, CHK2, ATR, FANCA, MRE11, etc. [150].