RET and neoplasm: Regorafenib, a novel oral multi-kinase inhibitor, disrupts kinases involved in tumor angiogenesis (VEGFR1, VEGFR2, VEGFR3, TIE2), tumorigenesis (KIT, RET, RAF1, BRAF, and BRAFV600E), and the tumor microenvironment (PDGFR and FGFR) (9).