Abstract
Micro (mi)RNAs are an endogenous non-coding small RNA comprised of 19-26 nucleotides. miRNAs regulate gene expression through the recognition of its 'seed sequence' and interactions with 3'-untranslated region of target miRNAs. Previous studies identified that miRNAs are associated with the onset and development of breast cancer and that a number of mutations in the coding DNA sequence of miRNAs affect its expression. Therefore, the present study aimed to screen differentially expressed miRNAs using miRNA expression profile chips to analyze the expression of miRNA (miR)-205 in 12 breast cell lines of different metastatic performance and benign proliferative variation as well as breast cancer via in-situ hybridization, and screen out single-nucleotide polymorphisms (SNPs) in the miR-205 coding gene region. In addition, the association between SNP and the clinicopathological features of breast lesions was investigated. The results of the present study demonstrated that the expression of miR-205 was decreased in breast cancer cells and tissues compared with benign lesions. SNPs in the miR-205 coding gene region were identified in tumor cell lines and as increasing lengths of the AGC repetitive sequence were lost, miR-205 expression increased. An association was identified between a number of SNPs in the miR-205 coding gene region and breast cancer, as well as between SNPs in miR-205 coding gene region and the clinicopathological features of breast cancer.