GSTM1 null polymorphisms is associated with laryngeal cancer risk: a meta-analysis

Many studies have examined the association between the GSTM1 (null or non-null genotype) polymorphism and laryngeal cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, a meta-analysis was performed. PubMed was searched for case-control studies published up to December 2013. Data were extracted and pooled odds ratios (OR) with 95 % confidence intervals (CI) were calculated. Ultimately, 23 studies, comprising 2,562 laryngeal cancer cases and 4,091 controls, were included. Overall, for null versus present, the pooled OR was 1.22 (95 % CI = 1.10-1.36), and the heterogeneity was found in all studies. In the stratified analysis by ethnicity, significant risks were found among Asians (OR = 1.71; 95 % CI = 1.34-2.19; P = 0.011 for heterogeneity) and in Caucasians (OR = 1.13, 95 % CI = 1.00-1.27; P = 0.036 for heterogeneity). In conclusion, this meta-analysis demonstrates that the GSTM1 null gene polymorphism is an increased risk of laryngeal cancer in Asians and Caucasians.