Numerous VEGF subtypes and VEGF receptors—including VEGFR-1 (FLT1) and VEGFR-2 (KDR)—as well as receptors for fibroblast growth factor (FGF) and platelet-derived growth factor (PDGF) are frequently overexpressed in the vascular endothelium of thyroid cancers and also trigger the MAP kinase signaling pathway [45]. Here, FLT1 is linked to thyroid cancer.