Signaling pathway and molecular-targeted therapy for hepatocellular carcinoma.

In recent years, molecular-targeted agents have been used clinically to treat various malignant tumors. In May 2009, sorafenib (Nexavar®) was approved in Japan for 'unresectable hepatocellular carcinoma (HCC)', and was the first molecular-targeted agent for use in HCC. To date, sorafenib is the only molecular-targeted agent whose survival benefit has been demonstrated in two global phase III randomized controlled trials, and has now been approved worldwide. Phase III clinical trials of other molecular-targeted agents comparing them with sorafenib as first-line treatment agents are now ongoing. Those agents target the vascular endothelial growth factor, platelet-derived growth factor receptors, as well as target the epidermal growth factor receptor, insulin-like growth factor receptor and mammalian target of rapamycin, in addition to other molecules targeting other components of the signal transduction pathways. This review outlines the main pathways involved in the development and progression of HCC and the agents that target these pathways. Finally, current status and future perspective will also be discussed.