GSTM1 and GSTT1 null polymorphism and antioxidant levels in oral submucous fibrosis, leukoplakia and oral cancer patients among a South Indian Population

Objective: We investigated the null polymorphism in GSTM1 and GSTT1 genes and the antioxidant levels in oral submucous fibrosis (OSMF), leukoplakia and oral cancer patients along with healthy controls in a South Indian cohort. Methods: Genotyping was done using multiplex PCR and the antioxidant levels were estimated using biochemical methods Association between genotypes and different diseased states was determined by odds ratio with 95% confidence interval (CI) and chi-square analysis and for antioxidant levels student's t-test was used. Results: The relative risk for GSTM1 and GSTT1 gene polymorphisms was statistically insignificant for the 3 patient groups vs. controls. Comparing the frequency of the null genotypes between the groups of patients only GSTM1 polymorphism revealed a significant difference between OSMF & oral cancer subjects (p = 0.02). Further, analysis of the antioxidant parameters shows ceruloplasmin levels to be significantly elevated between patient groups and controls and among OSMF vs. cancer patients (p < 0.05). Similarly, malondialdehyde and glutathione levels were found to be significantly elevated among cancer and both cancer and leukoplakia subjects respectively in comparison with controls (p < 0.05). Analysis between the patient groups revealed glutathione levels to be significantly elevated between OSMF vs. cancer patients and cancer vs. leukoplakia patients (p < 0.05). Conclusion: In conclusion, this study finds GSTM1 null genotype and antioxidants (ceruloplasmin and glutathione levels) to be significantly higher in oral cancers than in precancerous lesions, and suggesting that they might be associated with the malignant transformation of the oral precancers. (C) 2017 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.