Association of DNA double-strand break gene XRCC6 genotypes and lung cancer in Taiwan

The DNA repair gene X-ray repair complementing defective repair in Chinese hamster cells 6 (XRCC6) is thought to play an important role in the repair of DNA double-strand breaks. It is known that defects in double-strand break repair capacity can lead to irreversible genomic instability. However, the association of polymorphic variants of XRCC6 with lung cancer susceptibility has never been reported. In this hospital-based case-control study, the association of XRCC6 promoter T-991C (rs5751129), promoter G-57C (rs2267437), promoter G-31A (rs132770), and intron 3 (rs132774) polymorphisms with lung cancer risk in a Taiwanese population, was studied.In total, 358 patients with lung cancer and 716 healthy controls recruited from the China Medical Hospital in Taiwan were genotyped.The results showed that there were significant differences between lung cancer and control groups in the distribution of their genotypic (p=3.7×10(-4)) and allelic frequency (p=2.7×10(-5)) in the XRCC6 promoter T-991C polymorphism. Individuals who carried at least one C allele (TC or CC) had a 2.03-fold increased odds ratio of developing lung cancer compared to those who carried the wild-type TT genotype (95% conference internal=1.42-2.91, p=0.0001). For the other three polymorphisms, there was no difference between the case and control groups in the distribution of either genotypic or allelic frequency.In conclusion, the XRCC6 promoter T-991C, but not the promoter C-57G, promoter G-31A or intron 3, is associated with lung cancer susceptibility.