Definition

An imaging agent composed of the cyclic arginine-glycine-aspartic acid (cRGD)-based peptide derivative cyclo-(RGDyK) conjugated to the near-infrared (NIR) fluorophore ZW800-1, with potential use as a tumor-selective fluorescent imaging agent. Upon administration of the fluorescent imaging agent cRGD-ZW800-1, the cRGD moiety selectively binds to integrins, including alphaVbeta3, alphaVbeta5 and alphaVbeta6, expressed on tumor cells and tumor-associated vascular endothelium. Upon intraoperative fluorescence imaging, tumor cells and tumor-associated vascular endothelium expressing these integrins can be visualized. Integrins are transmembrane glycoproteins upregulated on proliferating tumor vessel endothelial cells and various cancer cells; their overexpression has been associated with neovascularization, differentiation, proliferation of tumor cells, metastasis and an overall poor prognosis.