MDM2 309 T/G polymorphism is associated with colorectal cancer risk especially in Asians: a meta-analysis.

The murine double minute 2 (MDM2) gene encodes an important regulator which mainly functions as an E3 ligase. The role of the MDM2 protein in the P53 pathway has been especially well-studied. In this study, our aim was to explore the relationship between MDM2 gene 309 T/G polymorphism and colorectal cancer risk. Performing both the overall meta-analysis and the subgroup meta-analysis based on ethnicity and source of controls with a total of 7 eligible studies (2,543 cases and 2,115 controls in all), we detected a significant colorectal cancer risk variation for TG versus GG (OR=0.73, 95% CI=0.62-0.86) in the overall analysis and another significant colorectal cancer risk variation for TG versus GG (OR=0.70, 95% CI=0.59-0.83) in the population-based controls' subgroup as well. Moreover, in the subgroup analysis based on ethnicity, significant associations were observed for all genetic models in Asians (OR=0.51, 95% CI=0.41-0.64 for TT versus GG; OR=0.64, 95% CI=0.53-0.78 for TG versus GG; OR=0.59, 95% CI=0.49-0.71 for dominant model; OR=0.69, 95% CI=0.57-0.82 for recessive model), while in Caucasians there was no obvious association. In summary, according to the results of our meta-analysis, the MDM2 309 G allele probably acts as a colorectal cancer risk factor, especially in Asians.