Comparative study of GST polymorphism in relation to age in COPD and lung cancer

Glutathione-S-transferase is involved in detoxification of xenobiotic compounds. GSTs gene polymorphisms have been considered as a potential modifier for the respiratory disease. COPD is a chronic inflammatory disease of the lungs, which progresses very slowly and the majority of patients are therefore elderly, and few study suggested that age is major risk factor for cancer. Whether age in metabolism of phases 2 enzyme gene polymorphisms GSTT1 and GSTM1 in Northern Indian COPD and lung cancer patients.

We have enrolled lung cancers, COPD patients and for the comparison we enrolled controls. Peripheral blood of COPD and lung cancer patients was taken after spirometry evaluation and histopathology. All genotyping were done by PCR-RFLP method. Independent sample t-test was performed to compare the mean values of continuous data. Statistical significance of differences in genotype frequencies between patients and controls was estimated by the chi-square two test.

GSTM1 null polymorphism was found to be significantly higher in COPD patients as compared with healthy controls (OR= 2.08; 95%; CI= 1.40-3.09; p= 0.0001), but there were no significant differences polymorphisms of GSTT1 null patients and healthy controls. In lung cancer GSTT1 null was found significantly associated (OR= 1.87; 95%; CI= 1.25-2.80; p= 0.002) however GSTM1 null was not associated with lung cancer patients. In subgroup analysis, we found GSTM1 Null significantly associated between age 46-65 years in COPD patients and healthy controls (62.2%/37.8%, OR= 3.20; 95%; CI= 1.97-5.18; p= 0.001), In lung cancer and controls (55.6%/44.4% OR= 1.07; 95% CI= 0.68-1.69; p= 0.774).

The effects of the GSTM1 null genotype seemed strong association with COPD and GSTT1 null genotype with lung cancer patients. GSTM1 null genotype is associated with an increased risk of COPD, especially in middle age.