RET and neoplasm: Regorafenib is an oral multikinase inhibitor of several protein kinases, including kinases involved in tumor angiogenesis (VEGFRs 1–3), oncogenesis (KIT, RET, RAF1, BRAF, and BRAFV600E), and development of the tumor microenvironment (PDGFR and FGFR) [14].