Identification of new miRNA biomarkers associated with HER2-positive breast cancers.

Human epidermal growth factor receptor 2 (HER2) is overexpressed/amplified in ∼30% breast cancers which are associated with poor prognosis. microRNAs are small non-coding RNA which play an important role in many physiological conditions including cancer. Here we screened and identified many miRNAs which are dysregulated by HER2 overexpression. In line with our quantitative PCR analysis data, in silico analysis of microRNA expression profiles of 1302 breast tumors revealed that miR-146a-5p is up-regulated and miR-181d and miR-195-5p are down-regulated in HER2-positive tumors. Furthermore, the expression levels of these microRNAs can significantly predict patient survival and thus potentially serve as new prognostic markers for HER2-positive breast cancer.