Regorafenib is a potent oral inhibitor of multiple kinases which might be involved in tumor angiogenesis (VEGFR-1, -2, -3, Tie-2), oncogenesis (KIT, RET, RAF-1, BRAF, BRAFV600E), and tumor niche formation (PGDFR, FGFR). The gene discussed is RET; the disease is neoplasm.