Site-specific meta-analysis of colon and rectum showed approximately 20% decrease in colon cancer risk only in the presence of CYP2C9 rs1799853 variant allele (OR = 0.79, 95% CI = 0.65–0.95, P = 0.01, I2 = 0) and ODC1 rs2302615 variant allele (OR = 0.80, 95% CI = 0.69–0.93, P = 0.004, I2 = 0) (S8 and S9 Tables). This evidence concerns the gene ODC1 and malignant colon neoplasm.