childhood leukaemia, genetic polymorphism, DNA repair
Aims. To explore the relationship between genetic polymorphism of DNA repair and susceptibility to childhood leukaemia. Materials and methods. A hospital-based case-control study, with 105 cases and 108 controls, was conducted, to analyze the distribution of X-ray radiation, polymorphisms of XRCC1 and APE1 in study subjects, and investigate the interaction between X-ray radiation and polymorphisms. Results. There was an increased risk of leukaemia in children exposed to X-ray radiation. XRCC1 399 and APE1 148 polymorphisms are related to susceptibility to acute leukaemia (OR=2.05, 95%CI 1.14-3.70; OR=1.94, 95%CI 1.05-3.58), while no gene-environment interaction effect was found. The analysis of haplotypes of polymorphisms in XRCC1 showed that children carrying Hap2 and Hap4 had an increased risk of leukaemia (OR=2.88, 95%CI 1.58-5.25; OR=3.76, 95%CI 1.17-12.08). Conclusion. Polymorphisms of XRCC1 and APE1 involved in base excision repair might influence the repair of DNA damage and the susceptibility to childhood leukaemia.