miR-196a2 C allele is a low-penetrant risk factor for cancer development

Published data on the association between miR-196a2 T/C polymorphism and cancer susceptibility are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 21 studies including 10,441 cases and 12,353 controls were involved in this meta-analysis. Overall, significantly elevated cancer risk was associated with miR-196a2 C allele when all studies were pooled into the meta-analysis (TC vs. TT: OR=1.23, 95% CI=1.11-1.36; CC vs. TT: OR=1.30, 95% CI=1.14-1.48; dominant model: OR=1.25, 95% CI=1.13-1.38). In the subgroup analysis by ethnicity, significantly increased risks were found in Asains (TC vs. TT: OR=1.24, 95% CI=1.10-1.40; CC vs. TT: OR=1.31, 95% CI=1.13-1.52; dominant model: OR=1.26, 95% CI=1.12-1.41) but with bordline statistical significance in Caucasians (TC vs. TT: OR=1.15, 95% CI=1.00-1.31). In the subgroup analysis by cancer type, statistically significantly increased risks were found for breast cancer (TC vs. TT: OR=1.15, 95% CI=1.01-1.31; CC vs. TT: OR=1.30, 95% CI=1.01-1.68; dominant model: OR=1.22, 95% CI=1.00-1.50; and recessive model: OR=1.11, 95% CI=1.01-1.23) and lung cancer (CC vs. TT: OR=1.30, 95% CI=1.10-1.54; and recessive model: OR=1.18, 95% CI=1.02-1.36). When stratified by study design, statistically significantly elevated risk was found in hospital-based studies (TC vs. TT: OR=1.30, 95% CI=1.13-1.49; CC vs. TT: OR=1.37, 95% CI=1.14-1.66; dominant model: OR=1.32, 95% CI=1.15-1.53) and population-based studies (CC vs. TT: OR=1.19, 95% CI=1.06-1.35; dominant model: OR=1.13, 95% CI=1.01-1.25). Despite some limitations, this meta-analysis suggests that the miR-196a2 C allele is a low-penetrant risk factor for cancer development.