VEGFR2 (Vascular endothelial growth factor receptor 2), also referred to Flk-1 (Fetal liver kinase 1) or KDR (Kinase insert domain receptor, a type III receptor tyrosine kinase), is a 152 kDa type V receptor tyrosine kinase of the VEGFR family, encoded by the KDR gene. This receptor is mainly expressed in endothelial cells and several vascular tumors and has been detailed in many other carcinomas, such as colorectal, mammary, lung non-small cell tumors. VEGFR2 is essential for endothelial cell functions of angiogenesis. It is a major responder to vascular endothelial growth factor signal by a phosphorylation cascade and ultimately regulates endothelial proliferation and migration. VEGFR2 is considered as a potential cell type marker based on the availability of VEGFR2 inhibitors. VEGFR3 (Vascular endothelial growth factor 3) belongs to the VEGF receptor family, with the other two members VEGFR1 (FLT1) and VEGFR2 (KDR/FLK1). This entry represents the VEGFR3 proteins. VEGF-C/VEGFR3 is indicated to activate human neural stem cells via ERK and AKT. In the catalytic loop of VEGFR3 in humans, an A to G transition corresponding to a histidine to arginine substitution has been associated with congenital hereditary lymphoedema. VEGFR3 is reported to be involved in tumor angiogenesis and growth and is up-regulated in tumor angiogenesis. VEGFR-3 play an essential role in the early blood vessel development in embryos. Additionally, VEGFR3 is essential for adult hippocampal neurogenesis.