Polymorphisms in the DNA repair genes XPD, XRCC1, XRCC3, and APE/ref-1, and the risk of lung cancer among male smokers in Finland.

Associations between lung cancer risk and common polymorphisms in the DNA repair genes xeroderma pigmentosum complementation group D (XPD), X-ray repair cross-complementing group 1 (XRCC1), XRCC3 and apurinic/apyrimidinic endonuclease/redox factor 1 were examined within a randomized clinical trial designed to determine whether alpha-tocopherol, beta-carotene, or both would reduce cancer incidence among male smokers in Finland. We found no direct association between lung cancer risk and any of the DNA repair genotypes studied, however, the association between XPD codon 751 genotype and lung cancer was modified by alpha-tocopherol supplementation, and the association between XRCC1 codon 399 genotype and lung cancer was modified by the amount of smoking. Our results suggest that common alterations in single DNA repair genes are not major determinants of lung cancer susceptibility among smokers.