The association between common genetic variant of microRNA-146a and cancer susceptibility.

Published data on the association between microRNA-146a (miR-146a) G/C polymorphism and cancer susceptibility are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 23 studies including 10,585 cases and 12,183 controls were used in the meta-analysis. Overall, no significant associations were found between miR-146a G/C polymorphism and cancer risk when all studies pooled into the meta-analysis (GC vs. CC: OR=1.08, 95% CI=0.94-1.24; GG vs. CC: OR=1.13, 95% CI=0.93-1.37; dominant model: OR=1.09, 95% CI=0.94-1.26). In the subgroup analysis by ethnicity, still no significant associations were found. In the subgroup analysis by cancer type, statistically significantly increased risks were found for papillary thyroid carcinoma (GC vs. CC: OR=3.44, 95% CI=1.86-6.34; GG vs. CC: OR=2.20, 95% CI=1.22-3.99; dominant model: OR=2.68, 95% CI=1.48-4.83). In the subgroup analysis by population-based controls or hospital-based controls, no statistically significantly increased risks were found. Despite some limitations, this meta-analysis suggests that the miR-146a G allele is a low-penetrant risk factor for papillary thyroid carcinoma development.