LUNG-CANCER RISK AND CYP1A1 GENOTYPE IN AFRICAN-AMERICANS

The role of CYP1A1 genotype in lung cancer risk was assessed in Africa n Americans through a case control study. The complete CYP1A1 genotype , including the frequency of all three polymorphisms (Msp1 [CYP1A12], exon 7 [CYP1A13] and African American specific [CYP1A1*4]) was deter mined by PCR on 307 controls and 105 cases of lung cancer among Africa n Americans. We have confirmed our earlier observation of a significan t increased risk (odds ratio = 2.8, 95% CI = 1.3-6.5) for lung adenoca rcinoma among people with the 4 polymorphism, although we did not obs erve any association of this polymorphism with overall lung cancer ris k. As previously reported, we found that lung adenocarcinoma patients with the 4 RFLP smoked significantly less than patients without this polymorphism, suggesting an important role in cancer risk of low expos ure levels to cigarette smoke in subjects carrying susceptibility poly morphisms, There was no association with the other two polymorphisms a nd lung cancer in this population. When we examined lung cancer risk a s a function of composite genotype, taking into account all three poly morphisms simultaneously in each subject, our preliminary data suggest ed an association of one rare genotype (homozygous Msp1, heterozygous exon 7 or 2/*2*3) with overall lung cancer risk (OR = 8.4, 95% CI = 1 .6-43.2).