Circular RNA shifts the miRNA binding panel and takes a role in hepatocellular carcinoma progression

Circular RNAs (circRNAs) are a novel type of RNA molecule that covalently joint its 5' and 3' end together and form a closed single strand annular. CircRNAs were first reported by Sanger et al. as a plant viroid RNA in 1976 (1). In decades, circRNAs were rarely investigated mainly because they are usually expressed at a relative low level.