The Association between Two MicroRNA Variants (miR-499, miR-149) and Gastrointestinal Cancer Risk: A Meta-Analysis

BACKGROUND MicroRNAs (miRNAs) are small RNA molecules that regulate the expression of corresponding messenger RNAs (mRNAs). Single nucleotide polymorphisms (SNPs) in miRNAs may contribute to cancer susceptibility due to changes in the microRNA's properties and/or maturation. The present study aimed to investigate the association between two miRNA polymorphisms (miR-499 rs3746444 and miR-149 rs2292832) and gastrointestinal (GI) cancer risk. METHODOLOGY/PRINCIPAL FINDINGS We conducted a search of case-control studies in PubMed, Wiley Online Library, Web of Science and the CNKI database. Eleven rs3746444 studies and six rs2292832 studies were included in our meta-analysis. The only obvious association between the miR-499 polymorphism and colorectal cancer susceptibility was found in the homozygote comparison (GG vs. AA: OR = 1.66, 95% CI: 1.02-2.70, P(h) = 0.10, P = 0.04). No significant association was found in the subgroup analysis for ethnicity and risk of hepatocellular and gastric cancer. A marginally elevated GI cancer risk was discovered in the recessive model for miR-149 (TT vs. TC+CC: OR = 1.15, 95% CI: 1.03-1.30, P(h) = 0.68, P = 0.02). Stratifying the results by ethnicity revealed a slight association between the recessive model and the Asian population (TT vs. TC+CC: OR = 1.14, 95% CI: 1.01-1.29, P(h) = 0.79, P = 0.03). CONCLUSIONS/SIGNIFICANCE The present meta-analysis indicates that miR-499 may be associated with the risk to colorectal cancer. MiR-149 may confer a marginally increased risk of susceptibility to gastrointestinal cancer, especially for Asians.