Objectives: The human GSTTP1 gene is polymorphic with an A-->G transition in exon 5 causing a replacement 105 Ile-->Val in the GSTP1 protein. The two isoforms, encoded by the alleles GSTP1*A and GSTP1*B, respectively, show different catalytic efficiencies towards some carcinogenic epoxides. In this study we have addressed the possible role of the Ile105Val GSTP1 polymorphism in lung cancer susceptibility.
Methods: The polymorphic site was genotyped by RFLP in a group of lung cancer patients (n = 164) and in two control groups (healthy smokers, n = 132; general population, n = 200). All patients and controls were Northwestern Mediterranean Caucasians of the same ethnic origin.
Results and conclusions: The cancer patients showed frequencies of GSTP1*A/A; GSTP1*A/B and GSTP1*B/B (50%, 38%, 11%, respectively) very similar to those of both control groups (healthy smokers: 48%, 41%, 11%). After adjusting for age, sex and smoking status, no association was found between the GSTP1*B allele and lung cancer risk (OR: 1.18; 95% CI: 0.67-2.07). The Ile105val GSTP1 polymorphism was also analysed in combination with the GSTM1 and GSTT1 genes. The results showed that allelism at GSTP1 did not increase the risk associated with the GSTM1 or GSTT1 deletions.