Vascular endothelial growth factor receptor 2 (VEGFR2), also known as kinase insertion region receptor (KDR), is a member of the class III subfamily of tyrosine kinase receptors (RTKs). VEGFR2 is more widely distributed and expressed in say to vascular derived endothelial cells than VEGFR1. VEGFR2 binds to VEGF-A (VEGF121, VEGF165, VEGF189 and VEGF206 shear variants), VEGF-C and VEGF-D. The difference between soluble VEGFR1 and VEGFR2 in blocking VEGF-induced cell proliferation and migration was highly significant. Soluble VEGFR2, in contrast to soluble VEGFR1, was unable to compete with VEGF for binding to endothelial cells expressing both VEGFR1 and VEGFR2. Soluble VEGFR2 only partially inhibits cell migration, whereas soluble VEGFR1 almost completely blocks VEGF-induced cell proliferation and migration.Binding of VEGF to soluble VEGFR2, but not to VEGFR1, is also dependent on heparin.The VEGF/VEGFR2 signaling pathway has an important role in oncogenesis and other pathologic angiogenic diseases. Inactivation of functional VEGFR2 function using blocking antibodies disrupts angiogenesis and prevents tumor cell spread.