Glutathione S-transferase T1 null genotype and laryngeal cancer risk: a meta-analysis

Glutathione S-transferase T1 (GSTT1) polymorphic variation has been implicated as a risk factor for various cancers. However, previous studies investigating the association between GSTT1 null genotype and laryngeal cancer risk in Asians reported conflicting outcomes. In the present study, the possible association of laryngeal cancer risk with GSTT1 null genotype was explored by a meta-analysis. Relevant studies were identified through a systemic search of PubMed and Chinese National Knowledge Infrastructure databases. Six studies with a total of 1,824 individuals were included in the meta-analysis. The pooled odds ratio (OR) with 95 % confidence interval (CI) was used to assess the association. Meta-analysis of all included studies showed that there was an obvious association between GSTT1 null genotype and laryngeal cancer risk in Asians (OR = 2.41, 95 % CI 1.27-4.57, P = 0.007, I (2) = 86 %). After adjusting for heterogeneity, there was still an obvious association between GSTT1 null genotype and laryngeal cancer risk in Asians (OR = 1.75, 95 % CI 1.36-2.24, P < 0.001, I (2) = 0 %). The findings from the meta-analysis suggest that GSTT1 null genotype is associated with laryngeal cancer risk in Asians.