RESUMO
Background: MicroRNAs (miRNAs) participate in gene regulation and the control of cancer-related mechanisms such as apoptosis, invasion and differentiation. Single nucleotide polymorphisms (SNP) of the miRNA encoding genes may influence the development of cancer. We hypothesized a link between miR-559 SNP rs58450758 and breast cancer.Materials & methods: Bioinformatics analyses were performed to predict the miR-559 target genes and the effect of the rs58450758 SNP on the stem-loop structure. A total of 129 breast cancer cases and 153 controls were genotyped using PCR-RFLP.Results: The recessive genotype (TT) was more common among breast cancer patients (23.3%) than among controls (2%). The non-dominant genotypes (CT+TT) were associated with breast cancer in patients (OR 3.62; 95% CI, 1.95-6.69; p < 0.0001). Bioinformatics analyses suggested that rs58450758 changes miR-559 secondary structure and forms new DICER sites in the pre-miRNA.Conclusion: The miR-559 rs58450758 variant is linked to breast cancer.