KDR and gastrointestinal stromal tumor: Sunitinib inhibits the tyrosine kinase activity of VEGF receptors, PDGF receptors, c‐kit, and RET, thereby inhibiting angiogenesis and lymphangiogenesis by blockade of VEGFR pathway, and tumor cell proliferation of GIST by blockage of c‐kit 16, 24, 25.