Investigating the rate of glutathione S-transferase T1 and M1 genes deletion in patients with lung cancer

Introduction: Glutathione S-tarnsferases (GST) gene family is one of the enzymes which is responsible for detoxifying mutagens and Carcinogens chemicals. People with null genotype of GSTM1 and GSTT1 genes are at higher risk of developing cancer, especially those who are related to smoking. The goal of this study was investigating the rate of glutathione S-transferase T1 and M1 genes deletion and their role in patients with lung cancer. Methods: In this case-control study, DNA extraction with salting out method was carried out upon 70 healthy controls and 30 patients with lung cancer. For determining deletions, a multiplex PCR was performed for GSTT1, GSTM1 and beta-globin as a control gene. Statistical analysis was done by Pearson's chi-square test and Fisher’s exact test. Results: Out of 30 patients and 70 controls: 3 (10%) cases and one (1.4%) control were double null genotype while in 19 (63.3%) patients and 59 (84.3%) controls, none of the genes were deleted. In 5 (16.7%) cases and 5 (7.1%) controls GSTT1 were deleted and in 9 (30%) cases and 7 (10%) controls GSTM1 was deleted. Statistical analysis showed that GSTM1 deletion is significantly higher in patients in comparison to the controls (P=0.018). Deletion of at least one of the GSTM1 or GSTT1 genes was significantly higher in patients group compar to the controls (P=0.033). Conclusion: Deletion in glutathione S-transferse genes was related to detoxifying carcinogenes and this could have been related to the development of lung cancer and in people with at least one deletion or both, the risk of lung cancer was more (especially GSTM1) comparing with those who have two wild type genotypes of these two genes