Study of correlation between genetic variants in three microRNA genes (hsa-miR-146a, hsa-miR-502 binding site, hsa-miR-27a) and breast cancer risk.

BACKGROUND AND AIM: MicroRNAs (miRNAs) represent noncoding RNAs that play a role in the gene regulation of oncogenes and tumor suppressors. Single nucleotide polymorphisms (SNPs) in miRNA genes are associated with risk of cancer. Some of these SNPs are more common including rs2910164 in the miR-146a, rs895819 in the miR-27a, and rs2910164 in the miR-502 binding site of the SET8. Our aim was to investigate the association between these polymorphisms and the risk of breast cancer in an Iranian population.

MATERIALS AND METHODS: In this case-control study, 240 breast cancer patients and 231 healthy people, matched by age and geographical region, were studied. After sample taking and total genomic extraction, genotyping was conducted by using PCR-RFLP and the results confirmed by direct sequencing. Then, allele and genotype frequencies and the association between the SNPs and breast cancer were investigated by the data analysis conducted in the SPSS version 20.

RESULTS: C allele in the variant rs895819 is associated with decreased risk of breast cancer. Such association was also obtained in dominant (OR=0.516) and overdominant (OR=0.527) models. The rs2910164 and rs16917496 SNPs were significantly associated with breast cancer (P=0.03 and 0.003, respectively).

CONCLUSION: This study determined that genetic changes in miR-146a and the miR-502 binding site of the SET8 can be effective on the increased risk of breast cancer. Such variation in miR-27a can have protective effects against breast cancer.