NTRK1 and neoplasm: Sorafenib is a multitargeted tyrosine kinase inhibitor that blocks the Ser/Thr kinase Raf and several receptor tyrosine kinases including vascular endothelial growth factor receptor- (VEGFR-) 2 and -3 and platelet-derived growth factor receptor- (PDGFR-) β to inhibit tumor cell proliferation and tumor angiogenesis.