Meta-analysis of associations between MDM2 SNP309 polymorphism and gastric cancer risk.

Epidemiological studies have been conducted to evaluate genetic variations of murine double minute 2 (MDM2) SNP309 associated with the risk of gastric cancer (GC), although evidence remains conflicting. To gain a better understanding of this relationship, a meta-analysis was performed. Several electronic databases were searched up to February 2013, in order to identify relevant case-control studies. Seven published case-control studies with 2,199 cases and 3,201 controls were included. In the overall analysis, significant associations between the MDM2 SNP309 variant and GC risk were found for G vs. T alleles (OR=1.35; 95% CI, 1.24-1.47), GG vs. TT (OR=1.88; 95% CI, 1.59-2.24), recessive model (OR=1.71; 95% CI, 1.49-1.96). Furthermore, stratified by cancer site, significant associations were observed in gastric cardia cancer for all the models, although no significant association was found in any of the models among non-gastric cardia cancer, with the exception of the recessive model. In the subgroup analysis by source of control, MDM2 SNP309 was associated with increased GC risk for the hospital-based case-control (HCC) study for the GG vs. TT, recessive model and for the population-based case-control (PCC) study for the GG vs. TT, recessive model. Following stratification by gender and infection status of Helicobacter pylori (HP) for the recessive model, a significant association was found only in the HP-positive infected individuals. However, no statistically significant association was observed in males, females or the HP-negative infected individuals. In summary, the association between MDM2 SNP309 and GC risk was statistically significant, particularly in gastric cardia cancer for the HP-positive population group.