The emerging role of non-coding circulating RNA as a biomarker in renal cell carcinoma.

INTRODUCTION: Bodily fluids like serum and plasma contain significant amounts of tumor-derived circulating cell-free RNA, which holds the potential to serve as diagnostic biomarker. Consequently, liquid biopsies comprising circulating cell-free RNA might help to facilitate personalized treatment strategies for patients with renal cell carcinoma (RCC). Areas covered: The present review provides a summary of the literature obtained by a PubMed search and covers the current knowledge on circulating non-coding cell-free RNA in patients with RCC. Expert commentary: Altered circulating microRNA and long non-coding RNAs signatures allow for the discrimination of patients with RCC and healthy individuals. On the other hand, little is known about non-coding RNA expression in benign tumors. Cell-free microRNA expression levels may help to identify patients at risk for disease recurrence. However, accurate determination of cell-free RNAs is methodologically challenging and currently no biomarker candidate has reached a sufficient level of clinical validation. Thus, short-term implementation of cell-free circulating microRNA into clinical routine seems unlikely.