RET and neoplasm: Regorafenib is a multikinase inhibitor (MKI) targeting tumour cells and their microenvironment by inhibition of several angiogenic RTKs (VEGFR-1, -2, -3, TIE-2), oncogenic RTKs (c-KIT, RET), stromal RTKs (PDGFR-B, FGFR1), intracellular signalling kinases (c-RAF/RAF-1, BRAF, BRAFV600E) and tumor immunity (CSF1R) [3,4].