Circular RNAs in hepatocellular carcinoma: Functions and implications

Abstract

At present, as hotspot members of the noncoding RNA network, circular RNAs (circ RNAs) with distinct properties and diverse pathophysiological functions are being increasingly delineated. Circ RNAs play roles at the epigenetic, transcriptional and posttranscriptional regulatory levels. Major studies have focused on their functions as efficient micro RNA sponges. The validated number of endogenous circ RNAs involved in hepatocellular carcinoma ( HCC) continues to increase. Altered circ RNA expression is associated with HCC occurrence, invasion, and metastasis. Moreover, the aberrant expression of circ RNAs is also significantly related to HCC tumor stage, size, differentiation and metastasis. Because they are exceptionally stable, highly conserved and have tissue‐specific expression patterns, some circ RNAs, including hsa_circ_0004018, hsa_circ_0003570, and hsa_circ_0005075, may be potential markers for the diagnosis of HCC. We herein summarize the current knowledge of HCC‐associated circ RNAs and present their implications for carcinogenesis and their potential value as diagnostic and prognostic biomarkers. Finally, we discuss the future directions of studies on HCC‐associated circ RNAs.