The present study was carried out to demonstrate the epidemiological value of microRNA (miRNA) in colorectal cancer (CRC) by investigating the association between miRNA gene polymorphisms and the susceptibility to CRC. Multiple meta-analyses of reported data were conducted, and odds ratio values and 95% confidence intervals were used to assess these associations. Stata 11.0 software was used to analyze the data and the modified Jadad quality score was employed to evaluate the quality of the retrieved studies. We retrieved 38 studies on the association between miRNA polymorphisms and risk of CRC, however only 15 met the requirements of the inclusion criteria. In conclusion, we identified a variety of miRNAs (miRNA-let-7, miR-34b/c, miR-146a, miR-603 and miR-149) gene polymorphisms that are associated with susceptibility to CRC. However, some miRNAs (miR-192a, miR-608 and miR-27a) are associated with CRC, but not susceptibility to CRC. The results have limitations given the relatively low number of studies available. Therefore, it is necessary to collect data from large sample-size studies to further validate the results.
Keywords: colorectal cancer; meta-analysis; microRNA; polymorphism; risk.