RAF1 and neoplasm: TKIs are orally administered small molecules that inhibit multiple pathways involved in angiogenesis, tumour growth, and metastasis Sorafenib inhibits RAF-1, BRAF, vascular endothelial growth factor receptor (VEGFR)1–3, and platelet-derived growth factor receptor (PDGFR)-β, kinases involved in angiogenesis and tumour proliferation.25