FLT4 and cancer: A novel oral tyrosine kinase inhibitor, surufatinib, which has a dual activity of anti-angiogenesis and immune regulation and simultaneously targets tumor angiogenesis (via VEGFR-1, VEGFR-2, VEGFR-3 and FGFR-1), has been approved in 2020 as a monotherapy for unresectable locally advanced or metastatic, progressive nonfunctioning, well differentiated (grade 1 or 2) extra-pancreatic neuroendocrine tumors (epNETs) in China, once again indicating that VEGF regulation may yield promising results in cancer treatment [152, 153].