Intravenous injection and fluorescence imaging of the near-infrared fluorescent in vivo blood pool imaging agent AngioSense (Figure 3G, Figure 5A) gave first indications that diminished tumor vascularization may be the cause for decreased perfusion of A375-EphB4 tumors (Figure 4A), as observed by small animal PET and radioluminography. Here, EPHB4 is linked to neoplasm.