KDR and neoplasm: Several other tumor vascular targets, such as vascular endothelial growth factor receptor 2 (VEGFR-2), αvβ3 and αvβ5 integrins and insulin-like growth factor binding protein 7 (IGFBP7), have been used to visualize tumor angiogenesis by PET, optical imaging and MRI [74,146,147,148].