Polymorphism of Xeroderma Pigmentosum group G and the risk of lung cancer and squamous cell carcinomas of the oropharynx, larynx and esophagus.

We investigated the effects of XPG His1104Asp polymorphism (rs17655) on the risk of lung cancer and squamous cell carcinomas of the oropharynx, larynx and esophagus (SCCOLE). This population-based case-control study involves 611 new cases of lung cancer, 601 new cases of oropharyngeal, laryngeal and esophageal cancers, and 1,040 cancer-free controls. The XPG polymorphism was assayed by PCR-RFLP method for 497 lung cancer cases, 443 cases of oropharyngeal, laryngeal and esophageal cancers and 912 controls. Binary and polytomous unconditional logistic regression models were fitted to assess the main effects and the effect modifications between the polymorphism and environmental exposures. With the adjustment for potential confounders, the XPG Asp1104Asp genotype was inversely associated with lung cancer (odds ratio [OR] = 0.62, 95% confidence limits [CL] = 0.38, 1.0) and SCCOLE (OR = 0.47, 95% CL = 0.27, 0.82), with the combined His1104His and His1104Asp genotypes as the referent. With subjects having genotype Asp1104Asp and no tobacco smoking exposure as the common referent, the ORs on lung cancer were 13 (95% CL = 4.4, 37) for heavy tobacco smoking (>20 pack-years), 1.9 (95% CL = 0.78, 4.5) for having at least one copy of 1104His, and 23 (95% CL = 9.5, 56) for the joint effect, respectively. Compared to non-smokers with the Asp1104Asp genotype, the adjusted OR on SCCOLE for heavy smokers (>20 pack-years) having at least one copy of 1104His was 8.0 (95% CL = 2.7, 24). Similarly, compared to non-drinkers with the Asp1104Asp genotype, the adjusted OR on SCCOLE for heavy drinkers (> or =3 drinks/day) with at least one copy of 1104His was 10 (95% CL = 2.7, 38). In conclusion, our study suggests that the XPG Asp1104Asp genotype may be associated with decreased susceptibility to lung cancer and SCCOLE.