<p>Sorafenib is a kinase inhibitor that decreases tumor cell proliferation in vitro. Sorafenib was shown to inhibit multiple intracellular (CRAF, BRAF and mutant BRAF) and cell surface kinases (KIT, FLT-3, RET, VEGFR-1, VEGFR-2, VEGFR-3, and PDGFR-&szlig;). Several of these kinases are thought to be involved in tumor cell signaling,&nbsp;angiogenesis, and&nbsp;apoptosis. Sorafenib inhibited tumor growth and angiogenesis of human&nbsp;hepatocellular carcinoma&nbsp;and&nbsp;renal cell carcinoma, and several other human tumor xenografts in&nbsp;immunocompromised&nbsp;mice.</p>