Although a direct causal relationship between the sustained loss of miR-122 function and HCC remains to be determined, downregulation of miR-122 has been described in HCC, with lower miR-122 levels correlating with a poor prognosis.27,28,29,30 miR-122 maintains hepatic function by down-regulating genes involved in cholesterol synthesis, such as HMG-CoA reductase.31 Therefore, controlling the function of miR-122 for extended periods of time may induce numerous side effects or liver dysfunction. The gene discussed is HMGCR; the disease is hepatocellular carcinoma.