Peptide-Based Probes for Cancer Imaging

Receptors for regulatory peptides are overexpressed in a variety of human cancers. They represent the molecular basis for in vivo imagingwith radiolabeled peptide probes. Somatostatin-derived tracers, designed to image the sst2-overexpressing neuroen-docrine tumors, have enjoyed almost 2 decades of successful development and extensive clinical applications. More recent developments include second- and third-generation somato-statin analogs, with a broader receptor subtype profile or with antagonistic properties. Emerging tracers for other peptide re-ceptors, including cholecystokinin/gastrin and GLP-1 analogs for neuroendocrine tumors, bombesin and neuropeptide-Y ana-logs for prostate or breast cancers, or Arg-Gly-Asp peptides for neoangiogenesis labeling, are also in current development. Application fields include both SPECT/CT and PET/CT