The polymorphisms in the MGMT gene and the risk of cancer: a meta-analysis.

Polymorphisms in the MGMT gene have been implicated in susceptibility to cancer, but the published studies have reported inconclusive results. The objective of the current study was to investigate the genetic risk of polymorphisms in the MGMT gene for cancer. A meta-analysis was carried out to analyze the association between polymorphisms in the MGMT gene and cancer risk. Five polymorphisms (Leu84Phe, Leu53Leu, Ile143Val, Lys178Arg, and -485C/A) with 98 case-control studies from 49 articles were analyzed. The results indicated that individuals who carried the Phe/Phe homozygote genotype of Leu84Phe had a 31 % increased risk of cancer compared with the Leu allele (Leu + Leu/Phe) carriers (odds ratio [OR] = 1.32, 95 % confidence interval [CI] = 1.15-1.52, P < 0.0001 for Phe/Phe vs. Phe/Leu + Leu/Leu). However, there was no significant association between the risk of cancer and the other four polymorphisms (Leu53Leu, Ile143Val, Lys178Arg, and -485C/A). In further stratified analyses for the Leu84Phe and Ile143Val polymorphisms, the increased risk of cancer remained in subgroups of Caucasians, patients with esophageal cancer for the Leu84Phe polymorphism, and patients with lung cancer for the Ile143Val polymorphism. Results from the current meta-analysis suggested that Leu84Phe and Ile143Val in the MGMT gene are risk factors for cancer. In the future, more studies should be performed to validate our results.