Significant association of XRCC4 single nucleotide polymorphisms with childhood leukemia in Taiwan

Background: The DNA repair gene XRCC4, a member of the protein family involved in non-homologous end-joining repair pathway, plays a major role in repairing DNA double-strand breaks. XRCC4 is important in maintaining the overall genome stability, and it is also thought to play a key role in human carcinogenesis. We investigated some novel polymorphic variants of XRCC4, including C-1622T (rs7727691), G-1394T (rs6869366), G-652T (rs2075685), C-571T (rs2075686), intron3 DIP (rs28360071), S247A (rs3734091) and intron7 DIP (rs28360317), and analyzed the association of specific genotype with susceptibility to childhood leukemia. Materials and Methods: In total, 266 children with leukemia and 266 age-matched healthy controls recruited from the China Medical Hospital in Central Taiwan were genotyped investigating the association of these polymorphisms with childhood leukemia. Results: We found differences in frequency of the XRCC4 G-1394T and intron 3 genotype, but not the XRCC4 codon 247, or intron 7, between the childhood leukemia and control groups. Our data indicated the G allele of G-1394T and deletion of intron 3 are clear risk factors of susceptibility to childhood leukemia (p=0.0022 and 0.0075). As for XRCC4 C-1622T and C-571T, there was no difference in the distribution between the two groups. The analysis of joint effect for XRCC4 G-1394T and intron 3 showed that individuals with GT at G-1394T and DD at intron 3 present the highest potential for developing childhood leukemia than other groups (odd ratio=4.94, 95% confidence interval=1.01-24.27, p=0.0404). Conclusion: Our findings suggest that the G allele of XRCC4 G-1394T and deletion of intron 3 may be responsible for childhood leukemia and may be useful in early detection of child leukemia.