Non-coding RNAs in hepatocellular carcinoma: molecular functions and pathological implications

Protein-coding sequence accounts for only 2% of the human genome, with the function of the remaining 98% of non-coding sequences in the human genome being largely elusiveA large number of small and long non-coding RNAs (ncRNAs) have been identified, and deregulation of ncRNAs has a critical role in liver carcinogenesisMicroRNAs negatively regulate gene expression at the post-transcriptional level; microRNAs can function as an 'oncomiRs' to repress tumour-suppressor genes or, vice versa, can act as a tumour suppressor to counteract oncogenesLong ncRNAs belong to functionally divergent groups of ncRNAs that regulate gene expression and other molecular functions through interacting with DNA, RNA and proteinsDeregulation of ncRNAs profoundly contributes to liver carcinogenesis of diverse aetiologies, liver cancer stem cell formation, hepatocellular carcinoma epigenetic reprogramming and cancer metastasisNon-coding RNAs are potential molecular markers and therapeutic targets of human hepatocellular carcinoma