BACKGROUND:Recent evidence suggests that the rs2910164 variant of miR-146a is associated with the development of certain types of cancer. Therefore, the aim of this study was to investigate the association of this genetic variant with susceptibility and prognosis in patients with colorectal cancer (CRC). MATERIALS AND METHODS:Genotyping analyses of miR-146a rs2690164 for risk and survival in CRC were performed in a case-control study (n=967) using a polymerase chain reaction (PCR)-restriction fragment length polymorphism assay. RESULTS:The C allelic frequency of miR-146 rs2690164 in the 399 patients and 568 controls was 61.9% and 53.9%, respectively. In the case-control study, those who possessed the CC genotype had a higher risk of CRC compared to those with the CG or GG genotype (odds ratio=1.569; 95% confidence interval=1.196-2.059; p=0.001), regardless of the tumor site. In the survival analysis of 343 patients with CRC who underwent curative surgery, those with CC genotype had a worse survival outcome compared with those with CG or GG genotype in a Kaplan-Meier survival analysis. Moreover, a multivariate analysis showed that the CC genotype of miR-146a rs2910164 was associated with worse relapse-free and disease-specific survival compared to the CG or GG genotype in a recessive model of the C allele, adjusted for patient and tumor characteristics (hazard ratio=2.120 and 2.349, p=0.005 and 0.007, respectively). CONCLUSION:The current study provides evidence that the miR-146a rs2690164 polymorphism, as the dominant model of the G allele, is associated with the susceptibility and prognosis of CRC.