However, in subgroup analysis by ethnicity, the results of our study suggested that there was a positive correlation between the MDM2 SNP309 polymorphism and CRC risk in Asian population (TG vs. TT: OR = 1.197, 95% CI = 1.055–1.358, P=0.005; GG+TG vs. TT: OR = 1.246, 95% CI = 1.106–1.404, P=0.000) and African population (GG vs. TT: OR = 8.665, 95% CI = 4.139–18.141, P = 0.000; GT vs. TT: OR = 8.935, 95% CI = 4.337–18.409, P= 0.000; GG+ GT vs. TT: OR = 8.812, 95% CI = 4.436–17.506, P= 0.000; GG vs. GT+ TT: OR = 1.843, 95% CI = 1.167–2.908, P=0.009; Figure 2). This evidence concerns the gene MDM2 and colorectal carcinoma.