Primary liver cancer is a global disease that is on the increase.Hepatocellular carcinoma(HCC)accounts for most primary liver cancers and has a notably low survival rate,largely attributable to late diagnosis,resistance to treatment,tumour recurrence and metastasis.MicroRNAs(miRNAs/miRs)are regulatory RNAs that modulate protein synthesis.miRNAs are involved in several biological and pathological processes including the development and progression of HCC.Given the poor outcomes with current HCC treatments,miRNAs represent an important new target for therapeutic intervention.Several studies have demonstrated their role in HCC development and progression.While many risk factors underlie the development of HCC,one process commonly altered is iron homeostasis.Iron overload occurs in several liver diseases associated with the development of HCC including Hepatitis C infection and the importance of miRNAs in iron homeostasis and hepatic iron overload is well characterised.Aberrant miRNA expression in hepatic fibrosis and injury response have been reported,as have dysregulated miRNA expression patterns affecting cell cycle progression,evasion of apoptosis,invasion and metastasis.In2009,miR-26a delivery was shown to prevent HCC progression,highlighting its therapeutic potential.Several studies have since investigated the clinical potential of other miRNAs with one drug,Miravirsen,currently in phaseⅡclinical trials.miRNAs also have potential as biomarkers for the diagnosis of HCC and to evaluate treatment efficacy.Ongoing studies and clinical trials suggest miRNA-based treatments and diagnostic methods will have novel clinical applications for HCC in the coming years,yielding improved HCC survival rates and patient outcomes. Primary liver cancer is a global disease that is on the increase. Hepatocellular carcinoma (HCC) accounts for most primary liver cancers and has a notably low survival rate, largely attributable to late diagnosis, resistance to treatment, tumor recurrence and metastasis. MicroRNAs (miRNAs / miRs) are regulatory RNAs that modulate protein synthesis. miRNAs are involved in several biological and pathological processes including the development and progression of HCC. Given the poor outcomes with current HCC treatments, miRNAs represent an important new target for therapeutic intervention. demonstrated their role in HCC development and progression. Many in risk factors underlie the development of HCC, one process commonly altered is iron homeostasis. Iron overload occurs in several liver diseases associated with the development of HCC including Hepatitis C infection and the importance of miRNAs in iron homeostasis and hepatic iron overload is well characterized. Aberrant miRNA expre ssion in hepatic fibrosis and injury response have been reported, as have dysregulated miRNA expression patterns affecting cell cycle progression, evasion of apoptosis, invasion and metastasis. In 2009, miR-26a delivery was shown to highlight HCC progression. have the investiga- tion of the clinical potential of other miRNAs with one drug, Miravirsen, currently in phase II clinical trials. miRNAs also have potential as biomarkers for the diagnosis of HCC and to evaluate treatment efficacy. Ongoing studies and clinical trials suggest miRNA-based treatments and diagnostic methods will have novel clinical applications for HCC in the coming years, yielding improved HCC survival rates and patient outcomes.