Aim: 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.
Materials and methods: In total, 358 patients with lung cancer and 716 healthy controls recruited from the China Medical Hospital in Taiwan were genotyped.
Results: 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.
Conclusion: 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.