FLT1 and metastatic colorectal cancer: Regorafenib is an oral multikinase inhibitor targeting VEGFR1–3, c-KIT, RAF, and FGFR, which inhibits tumor angiogenesis and significantly delays tumor growth, and has been approved for treating metastatic colorectal cancer, advanced gastrointestinal stromal tumors, and hepatocellular carcinoma (45, 46).