Despite high incidence rates of prostate cancer, the genetic basis of this disease is not well understood. An association between risk and the CYP1A1 polymorphism has been noticed for several cancers, and the GSTM1 gene is one of the most extensively studied genes concerning polymorphism and cancer risk. These gene polymorphisms may play a role in the development prostate cancer (PCa) in Turkish populations; we therefore assessed the association of CYP1A1 and GSTM1 polymorphisms in patients with PCa in our population through a case-control study. One hundred patients with PCa and 107 control subjects were analyzed with an allele-specific polymerase chain reaction method. No statistical differences in the distribution of the CYP1A1 IIe/Val genotype among PCa individuals were observed (OR = 1.076, 95% CI = 0.605-1.913). The patients with CYP1A1 Val/Val revealed a 2.8-fold higher risk of having prostate cancer than those with the wild-type IIe/IIe (OR = 2.846, 95% CI = 1.004-8.064). In other words, the presence of the Val/Val genotype significantly increased the risk of prostate cancer. The GSTM1 null genotype was found in 13.1% of the control subjects; no statistical differences were noted in the frequency of the null genotype in patients with PCa (OR = 1.558, 95% CI = 0.735-3.305). We also analyzed the effects of the CYP1A1 and GSTM1 genotypes in combination; however, no significant difference between cases and controls was observed in our study population. These data suggest that the CYP1A1 gene polymorphism may be associated with PCa susceptibility in Turkish men and that further studies will be needed to clarify the role of such variations in determining susceptibility to PCa. (C) 2004 Elsevier Inc. All rights reserved.