Roadmap of miR-122-related clinical application from bench to bedside.

INTRODUCTION: microRNA (miRNA) regulates target gene expression to influence many physiological and pathophysiological processes. The liver-specific miRNA, miR-122, contributes to liver function and plays a very important role in hepatic diseases including the viral hepatitis C (HCV). For this reason, developing an miR-122-related clinical application could be very useful in managing or treating many hepatic disorders. AREAS COVERED: This review introduces the basic concepts of miRNA and miR-122. It also discusses the possibility of miR-122 as a biomarker and summarizes the results of anti-miR-122 treatment from basic research to a Phase IIa clinical trial. Furthermore, the authors discuss the potential opportunities and challenges found in clinical trials with miravirsen. EXPERT OPINION: miR-122 may be a useful biomarker as both a diagnostic and prognostic tool. Furthermore, miravirsen is a novel treatment with great potential for hepatic disease treatment, especially in HCV. However, there is certainly the need for future investigations to better determine whether miR-122 is really specific for liver. It is also important to elucidate whether miR-122 is actually specific for HCV genome and further investigate the therapeutic potential of miravirsen. Only once these studies have been completed can anti-miR-122 treatment potentially enter the clinical practice.