Glutathione S-transferase M1 polymorphism and lung cancer risk in African-Americans

Glutathione S-transferase M1 (GSTM1) can detoxify many carcinogens, includi ng polycyclic aromatic hydrocarbons such as those from cigarette smoke. Tho ugh a number of studies have been published about the association between G STM1 polymorphism and lung cancer, this association has received limited at tention in the African-American population. We conducted a case-control stu dy to investigate the role of GSTM1 polymorphism in the development of lung cancer in African-Americans. Specimens of DNA from 117 lung cancer cases a nd 120 controls were assayed for detection of GSTM1 genotype by polymerase chain reaction (PCR), The odds ratios (ORs) and 95% confidence intervals (C Is) for lung cancer associated with homozygous deletion of the GSTM1 gene a nd other risk factors were estimated by logistic regression. Thirty-seven o f the 117 cases (31.6%) and 24 of the 120 controls (20.0%) had the GSTM1 nu ll genotype; the OR was 2.10 (95% CI 1.07-4.11) after adjustment for age, g ender and smoking. The association was higher for squamous cell carcinoma ( OR 2.98, 95% CI 1.09-8.19) than for adenocarccnonma (OR 1.95, 95% CI 0.81-4 .66). We observed a stronger association between GSTM1 null genotype and lu ng cancer among heavy smokers with greater than or equal to 30 pack-years ( OR 4.35, 95% CI 1.16-16.23). This association was also found in squamous ce ll carcinoma (OR 6.26, 95% CI 1.31-29.91), In the analysis combining GSTM1 polymorphism and smoking, smokers with the null genotype had high risk (OR 8.19, 95% CI 2.35-28.62) compared with non-smokers with the wild-type genot ype, and the risk increased with smoking cigarette pack-years (P = 0.0001 f or trend). Our results suggest that GSTM1 polymorphism plays a role in the development of lung cancer and modifies the risk for smoking-related lung c ancer in African-Americans.