GSTM1 null genotype and gastric cancer risk in the Chinese population: an updated meta-analysis and review.

Although a number of studies have been conducted on the association between the GSTM1 null genotype and gastric cancer in People's Republic of China, this association remains elusive and controversial. To clarify the effects of the GSTM1 null genotype on the risk of gastric cancer, an updated meta-analysis was performed in the Chinese population. Related studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) up to November 5, 2014. A total of 25 studies including 3,491 cases and 5,921 controls were included in this meta-analysis. Overall, a significant association (odds ratio [OR] =1.47, 95% CI: 1.28-1.69) was found between the null GSTM1 and gastric cancer risk when all studies in Chinese population were pooled into the meta-analysis. In subgroup analyses stratified by quality score, geographic area, and source of controls, the same results were observed. Additionally, a significant association was found both in smokers and non-smokers. This meta-analysis showed that the null GSTM1 may be a potential biomarker for gastric cancer risk in Chinese, and further studies with gene-gene and gene-environment interactions are required for definite conclusions.