Glutathione S-transferase GSTM3 and GSTP1 genotypes and larynx cancer risk

Glutathione S-transferases (GSTs) are involved in detoxification of reactiv e metabolites of carcinogens and, therefore, could be potentially important in susceptibility to cancer. The associations between larynx cancer risk a nd GSTM3 and GSTP1 gene polymorphisms, either separately or in combination with GSTM1 and GSTT1 gene polymorphisms, were evaluated using peripheral bl ood DNA from 129 cancer patients and 172 controls, all regular smokers. The frequencies of GSTM3 AA, AB, and BE genotypes were 60.5%, 36.4%, and 3.1% in cases and 72.7%, 24.4%, and 2.9% in controls, respectively. The frequenc ies of GSTP1 AA, AG, and GG genotypes were 48.1%, 40.3%, and 11.6% in cases and 50.0%, 37.2%, and 12.8% in controls, respectively. Multivariate logist ic regression analyses did not reveal any association between the GSTP1 (AG or GG) genotype and larynx cancer [odds ratio, 1.1; 95% confidence interva l (CI), 0.7-2.0]. In contrast, a significant increase in risk was related t o the GSTM3 (AB or BE) genotype (odds ratio, 2.0; 95% CI, 1.1-3.4). The com bined GSTM3 (AB or BE) and GSTM1-null genotype conferred a 4-fold risk (95% CI, 1.6-10.1) of larynx cancer as compared with the combined GSTM3 AA and GSTM1-positive genotype. However, the effect of GSTM3 (AB or BE) genotype w as similar among individuals with GSTM1-positive or GSTM1-null genotypes.