| The onset of angiogenesis is believed to be an early event in tumorigenesis and may facilitate tumor progression and metastasis. Several growth factors with angiogenic activity have been described. These include FGF, PDGF, vascular endothelial growth factor (VEGF), VEGF-B, VEGF-C, VEGF-D (or FIGF), EG-VEGF and placenta growth factor (PlGF). VEGF-D undergoes a complex proteolytic maturation, generating multiple processed forms which bind and activate VEGFR-2 and VEGFR-3 receptors. This protein is structurally and functionally similar to vascular endothelial growth factor C. |