XRCC1 and acute lymphoblastic leukemia: By critically reviewing 7 studies on XRCC1 Arg399Gln polymorphism (a total of 880 cases and 1311 controls), 3 studies on XRCC1 Arg280His polymorphism (a total of 345 cases and 554 controls), and 6 studies on Arg194Trp polymorphism (a total of 783 cases and 1180 controls), we performed a meta-analysis to indicate that the polymorphisms in XRCC1 Arg399Gln was significantly associated with risk of childhood ALL.