Rabbit Anti-Human VEGFC polyclonal antibody for IHC-P. Three cell membrane receptor tyrosine kinases, FLT (also designated VEGF-R1) , FLK-1 (also designated VEGF-R2) and FLT-4 (also designated VEGF-R3) , putatively involved in the growth of endothelial cells, are characterized by the presence of seven immuno-globulin-like sequences in their extracellular domain. On the basis of structural similarity to FLT and FLK-1, it has been speculated that FLT-4 might represent a third receptor for eother VEGF or a VEGF-related ligand.