FLT4 and neoplasm: However, results of in vitro studies have since shown that sorafenib is a potent multikinase inhibitor, which also targets receptor tyrosine kinases associated with tumour angiogenesis (VEGFR-2, VEGFR-3, PDGFR-β) and tumour progression (c-KIT, FLT-3) (Wilhelm et al, 2004).