DNA repair plays a crucial role in protection from cancer-causing agents. Therefore, a reduced DNA repair capacity can increase the susceptibility to lung cancer. The XPC gene contains 15 exons and encodes a 940 amino acid protein that plays a central role in DNA damage recognition of the nucleotide excision repair pathway, which is a major DNA repair mechanism removing the bulky-helix distorting DNA lesions caused by smoking. Recently several polymorphisms in the XPC gene were identified. In addition, it is possible that these polymorphisms may affect the DNA repair capacity, which modulate cancer susceptibility. The relationship between codon 499 and 939 polymorphisms, and a poly(AT) insertion/deletion polymorphism in the XPC gene, and the lung cancer risk were investigated.

The genotypes were determined using either PCR or PCR-RFLP analysis in 219 male lung cancer patients and 150 healthy males controls.

The frequencies of the genotypes (Val499Ala, PAT and Lys939Gln) among the cases were not significantly different from those of the controls. There was no significant associantion between these polymorphism and the lung cancer risk when the analyses were stratified according to age, smoking status and the pack-years of smoking. Moreover, the genotypes had no apparent relationship with any of the histological types of lung cancer. There was a linkage disequilibrium among the Val499Ala, PAT and Lys939Gln polymorphisms. The PAT polymorphism had a strong linkage disequilibrium with the Lys939Gln polymorphism (kappa value=0.87). The XPC haplotypes showed no significant association with the lung cancer risk.

These results suggest that XPC Val499Ala, PAT and Lys939Gln polymorphisms are not major contributors to the individual lung cancer susceptibility in Koreans.