CHEK1 and neoplasm: Asmentioned, tumors with low expression of SLFN11 and PARGdownregulation depend on the ATR-CHK1-WEE1 axis to tolerate replication stress.In vitro and in vivo ATR-CHK1-WEE1 pathwayinhibition re-sensitizes tumor cells to platinum and PARPi.86 Forinstance, ATR initiates DDR through several processes.