A race-specific genetic polymorphism in the CYP1A1 gene is not associated with lung cancer in African Americans

In a case-control study, we tested the hypothesis that a previouslydescribed African American-specific polymorphism in an intron3' to the coding region of the CYP1A1 gene was associated withthe occurrence of lung cancer. The study population included72 African Americans with newly diagnosed, untreated lung cancerwho presented to collaborating clinicians at the Universityof Texas M.D.Anderson Cancer Center and from county, communityand Veterans Administration hospitals in the Houston metropolitanarea. Controls were 97 African Americans, frequency-matchedon gender and age, recruited from community centers, churches,cancer screening programs and from among hospital employees.The prevalence of the variant CYP1A1 genotype did not differbetween the cases and controls. The odds ratio for individualswith one or more copies of the variant allele was 0.64 [ 95%confidence interval (CI) 0.3– 1.4]. Overall, 20.7% ofthe population had one or more variant alleles; the prevalencein cases was 16.7% and in controls it was 23.7%. Two individualswith the homozygous variant genotype were controls while oneindividual with lung cancer was found to have the homozygousvariant genotype. The lack of an association between genotypeand lung cancer persisted after subgroup analysis for lifetimecigarette smoking history and tumor histology was performed.The sample size of this study is sufficient to detect odds ratiosof three or greater; associations of this magnitude are similarto those reported in studies of a different polymorphism inthe same region of the CYP1A1 gene in Japanese. Thus, it isunlikely that this polymorphism is associated with sizable risksfor tobacco-induced lung cancer in this population subgroup.