FLT4 and hepatocellular carcinoma: Sorafenib is an inhibitor of several receptor tyrosine kinases involved in neovascularization, including VEGFR2, VEGFR3, and platelet-derived growth factor (5); it has shown efficacy against a wide variety of tumors in preclinical models, such as breast, colon, and pancreas carcinoma, and it has been approved for the treatment of hepatocellular carcinoma (9, 21).