Associations Among Glutathione S-Transferase T1, M1, and P1 Polymorphisms and the Risk of Oral Leukoplakia.

Abstract

The potential association between glutathione S-transferase (GST) M1, T1, P1 polymorphisms and the risk of oral leukoplakia (OLK) has been extensively studied. However, the results of previous studies have been contradictory. In an effort to resolve these different findings we performed a meta-analysis. Eligible articles were identified by a search of PubMed, the China National Knowledge Infrastructure (CNKI), MEDLINE, EMBASE, and the Web of Science databases through December 1, 2015. Crude odds ratios (ORs) with 95% confidence intervals were used to evaluate the risk of OLK by tobacco use, ethnicity, and OLK subtype. A total of 3122 cases and 6037 controls were included in the meta-analysis. The results indicated that the glutathione S-transferase Mu1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms increase the risk of OLK (OR = 1.838, 95% CI = 1.582-2.134 and OR = 1.337, 95% CI = 1.132-1.579, respectively), especially in the groups with tobacco use (OR = 2.478, 95% CI = 2.032-3.020 and OR = 2.034, 95% CI = 1.486-2.783, respectively). Conversely the glutathione S-transferase P1 (GSTP1) polymorphism did not demonstrate a significant relationship with OLK risk (OR = 1.139, 95% CI = 0.900-1.442). The GSTM1 and GSTT1 null polymorphisms were identified as being significantly associated with an increased risk of OLK within the German and Indian populations: German subgroup (GSTM1: OR = 11.555, 95% CI = 7.465-17.884), Indian subgroup (GSTM1: OR = 1.333, 95% CI = 1.084-1.638; GSTT1: OR = 1.332, 95% CI = 1.057-1.679). Our findings provide evidence that the GSTT1 and GSTM1 null polymorphisms may be risk factors of OLK, especially for persons who use tobacco, whereas the GSTP1 polymorphism does not contribute to the development of OLK. Thus, detection of GSTT1 and GSTM1 null polymorphisms may be promising biomarkers for the OLK susceptibility.