[Relationship between polymorphisms of DNA repair gene XRCC3 and susceptibility to lung cancer].

OBJECTIVE

To study the polymorphisms of DNA repair gene XRCC3 and the relationship between genetic variations and susceptibility to lung cancer.

METHODS

A case-control study of 291 patients with lung cancer and 273 cancer-free subjects as a control group was conducted from September 2006 to January 2007 to detect XRCC3 polymorphisms at loci. Genotypes of XRCC3 were analyzed by real time PCR using Taqman probes.

RESULTS

Compared with never smoking subjects with wild homozygous genotype (Thr/Thr), smokers with the same genotytpe (Thr/Thr) had increased risk of lung cancer, adjusted odds ratio (OR) was 2.467 (95% CI: 1.49 - 4.08, P < 0.001). Smokers with the heterozygous genotype (Thr/Met) also had increased risk of lung cancer, adjusted OR was 2.283 (95% CI: 1.21 - 6.60, P < 0.05). XRCC3 codon 241 homozygous genotype (Thr/Thr) and pack-years of smoking less than 30 had a weak protective effect on adenocarcinoma (OR = 0.49, 95% CI: 0.26 - 0.93, P < 0.05). Allel Met of XRCC3 codon 241 and smoking conferred an increased risk of squamous cell carcinoma (OR = 9.69, 95% CI: 3.27 - 28.72, P < 0.01). Those with allel Met of XRCC3 codon 241 and pack-years of smoking less than 30 or more than 30 had different risk of squamous cell carcinoma, the OR was 8.00 (95% CI: 1.97 - 32.52, P < 0.01), and 11.67 (95% CI: 2.98 - 45.73, P < 0.01) respectively.

CONCLUSION

The results demonstrated that genetic polymorphism of XRCC3 DNA repair gene may contribute to the susceptibility to lung cancer and have synergistic effect with smoking.