Several polymorphisms in cytochrome P-450s (CYP)s and Glutathione S-transferases (GST)s have been reported to be associated with survival rates of patients with non-small cell lung cancer (NSCLC) but the studies in this regard are scarce and the results are contradictory. In this study, CYP1A1 (Ile462Val), CYP1B1(Asn453Ser), GST M1, GSTP1 exon 5 (Ile105Val) and exon 6(Ala114Val) and GSTT1 polymorphisms were determined in 138 patients with advanced NSCLC to evaluate their role in survival. Of the studied CYP and GST polymorphisms only GSTP1 exon 6 variant significantly altered (improved) the survival compared to wild type (p=0.036) with median survival of 22.2 months and 16.1 months, respectively. Multivariate analysis also revealed a significant reduction of adjusted hazard ratio of death associated only with the GSTP1 exon 6 variant genotype of 0.45 (95% confidence interval (95% CI), 0.23-0.89, p=0.022). These results show that the GSTP1 exon 6 variant genotype is associated with improved survival in the patients with advanced NSCLC.

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Several studies focused on investigating genetic polymorphisms in order to estimate genetic contribution to lung cancer often showed conflicting results. In this study, we investigated the role of GSTM1, GSTT1, GSTP1 exon 5 and exon 6 polymorphisms on developing lung cancer and histological subtypes in 213 lung cancer patients and 231 controls. GSTM1 null, GSTT1 null, and GSTP1 exon 5 variant genotypes did not show a significant risk for developing lung cancer overall. Significant association was noted between GSTP1 exon 6 variant genotypes and overall lung cancer risk (OR 2.17, 95% CI 1.25-3.78; P = 0.006). These results show that GSTP1 exon 6 polymorphism might be an important factor in determining lung cancer susceptibility in a Turkish population.

Recent years have seen a growing evidence of ethnic differences in the frequency of glutathione S-transferase omega 1 (GSTO1) A140D gene polymorphism, which is associated with various cancers such as breast and liver. Until now however, no association has been investigated between the GSTO1 A140D polymorphism and lung cancer. The aim of our study was to see if there was one in the Turkish population. To do that, we identifi ed GSTO1 A140D polymorphism in 214 unrelated healthy individuals and 172 patients with non-small cell lung cancer (NSCLC) using the polymerase chain reaction -restriction fragment length polymorphism (PCR-RFLP) method. The frequencies of A/A (wild type), A/D (heterozygous mutant), and D/D (homozygous mutant) GSTO1 A140D genotypes in healthy subjects were 48 %, 41 %, and 11 %, respectively. In NSCLC patients they were 48 %, 45 %, and 7 %, respectively. We found no signifi cant association between the GSTO1 A140D gene polymorphism and NSCLC or its histological subtypes, namely squamous cell carcinoma or adenocarcinoma. Furthermore, this polymorphism did not correlate with smoking. Our study is the fi rst to show that the frequency of GSTO1 A140D gene polymorphism in the Turkish population is similar to other Caucasian populations and that this polymorphism is not associated with susceptibility to NSCLC.

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