GSTM1 and GSTT1 polymorphisms, tobacco use as risk factors for nasopharyngeal carcinoma in maghreb population — A case-control study

Abstract

Nasopharyngeal carcinoma (NPC) has known environmental risk factors, notably smoking, and enzymes that biotransform carcinogens. The interindividual differences observed in the metabolism of tobacco carcinogens substances have been attributed to the genetic polymorphism of genes, which code for enzymes involved in detoxification. Polymorphic deletions of GSTM1 and GSTT1 genes involved in the detoxification of potentially carcinogenic agents may be a risk factor for NPC. To investigate the roles of genetic variations of GSTM1 and GSTT1 in NPC susceptibility in the Northern African population, we conducted a case-control study of 132 NPC cases and 200 controls. DNA was isolated from blood for cases and controls. GSTM1 and GSTT1 deletion variants were genotyped by multiplex PCR assays. Allelic frequencies between the two groups were compared using a χ2 test, and odds ratio (OR) with 95% confidence intervals were calculated. The results indicate that an excess of the GSTM1 null genotype was observed in cases compared with controls, 50% versus 33%. The genotypic frequency of GSTM1 null genotype between controls and patients was significantly different. This genotype confers an increased risk of NPC [OR = 2.18; CI 95% (1.23–5.33). The association between GSTM1 and increased NPC risk in this cases-controls study was present among both men [OR = 2.59; CI95% (1.81–4.32)] and smokers. No significant association was observed between null GSTT1 genotype and the risk of CNP.