Molecular epidemiologic studies have reported relationships between lung cancer and polymorphisms in genetic susceptibility genes, including metabolic enzymes (cytochrome P450s, glutathione S-transferases) and DNA repair enzymes (hOGG1, XRCC1), with the goal of elucidating their relationships with lung cancer susceptibility (13, 15, 16). This evidence concerns the gene XRCC1 and lung cancer.