RAF1 and hepatocellular carcinoma: Sorafenib, the first approved agent for systemic therapy of advanced HCC, is a multi-targeted tyrosine kinase inhibitor (mTKI) that can target several protein receptors such as vascular endothelial growth factor receptor (VEGFR), or platelet-derived growth factor receptor (PDGFR) to impair vascular angiogenesis as well as block several cell signaling pathways such as Raf-1, B-Raf, and kinase activity in the Ras/Raf/MEK/ERK signaling pathways to inhibit tumor proliferation (3).