Abstract
BACKGROUND: MicroRNAs play a key role in regulating gene expression in human cells. Single-nucleotide variants in these molecules have been linked to cancer development, particularly breast cancer (BrC). AIM: To analyze the association of three microRNA polymorphisms with the risk of BrC in women from western Mexico. METHODS: This case-control study included 71 women diagnosed with BrC and 215 women without BrC. Genotypes were determined using a real-time polymerase chain reaction allelic discrimination assay. Multiple genetic models - dominant, recessive, over-dominant, additive, and multiple comparison - were applied to assess the risk. RESULTS: The over-dominant model showed that the C/T genotype of MIR196A2 (rs11614913) is a protective factor against the ductal histological subtype of BrC in women from western Mexico [odds ratio (OR) = 0.4687, 95% confidence interval (CI): 0.2205-0.9963, P = 0.0489]. A protective effect was also observed for the C/A genotype (OR = 0.2612, 95%CI: 0.0900-0.7582, P = 0.0135) and A allele (OR = 0.2826, 95%CI: 0.0993-0.8044, P = 0.0179) of MIR618 (rs2682818). No significant association was found between MIR200C (rs73262897) and BrC risk. CONCLUSION: The C/T genotype of rs11614913 in MIR196A2, and C/A genotype and A allele of rs2682818 in MIR618, are associated with a protective effect against BrC in women from western Mexico.