Individual susceptibility to cancer induced by environmental agents may be influenced by polymorphic metabolic genes responsible for the activation or detoxification of carcinogens．The association between genetic polymorphisms in cytochrome P4501A1 (CYP1A1) and lung cancer susceptibility has been extensively studied．The various CYP1A1 alleles exhibit population frequencies that depend on race and ethnicity．An increased risk of lung cancer in Asians was found to be associated with genetic polymorphisms in CYP1A1．However，reports from Caucasians are not consistant，probably suggesting the ethnic-sepecific effect of the polymorphisms in the locus on the cancer．Evidence also exists for the association between levels of carcinogen-DNA adducts or frequency of oncogene and tumor suppressor gene mutations and CYP1A1 polymorphisms．These findings provide a better understanding of the relationship between CYP1A1 and lung cancer susceptibility．