BRCA1 and BRCA2 mutations confer an increased lifetime risk of breast cancer; however, the associations of microRNA (miRNA) binding site single nucleotide polymorphisms (SNPs) in 3ʼ untranslated regions (3ʼ-UTR) of BRCA1 and BRCA2 with breast cancer (BC) risk were reported. In this case–control study (119 BC patients and 100 matched controls), two SNPs (rs12516 and rs15869) were selected in the 3ʼ- UTR of BRCA1 and BRCA2 genes, which were within miRNA-binding seed regions and might have potential function to regulate the expression of BRCA1/BRCA2. Unconditional logistic regression model was used to analyze the association between three SNPs and BC risk, and Popgen software was performed to get allele and genotype frequency of BRCA1 rs12516 and BRCA2 rs15869 in cases and controls of this study. A novel finding showed that AT [odds ratio (OR) 2.3705, 95% confidence interval (CI) 1.2927 to 4.3470] genotype of rs15869 in BRCA2 could increase the risk of BC. Also, in the age >43 comparison between cases and control (p=0.0472) indicates the BRCA1 rs12516 had statistical significant association with breast cancer risk. The sequencing results of target regions in exon 5 and 8 of P53, mir504b and mir125 genes and rs8176318 variant in 3ʼ-UTR of BRCA1 were showed no new mutation in these five target regions.
