RESEARCH ARTICLE Feasibility of urinary micro

DOI 10.1186/s12885-015-1190-4NAs in serum and plasma. This opened the field for these2German Cancer Consortium (DKTK), Heidelberg, Germany Full list of author information is available at the end of the articleBackground Small non-coding microRNAs (miRNAs, miRs) with a length of approximately 22 nucleotides are important post-transcriptional regulators of numerous human genes. MiRNAs modulate the expression of tumor suppressor genes as well as oncogenes [1-3]. In breast cancer (BC), emerging evidence suggests a potential role for deregu-lated miRNAs as modulators of carcinogenesis, prolifera-tion, apoptosis and drug-resistance, respectively [4]. Most data exist for tumor tissue or breast cancer cell line-based miRNA expression profiles [5,6]. However, there are nu-merous hypotheses for a pivotal role of miRNAs in inter-cellular communication [7,8] partially based on the leakage of miRNAs in circulation [9] as well as by active and passive export mechanisms, respectively [9]. Recent studies documented the feasibility to detect stable miR