The potential of established tumor-specific proteins, such as carcinoembryonic antigen (CEA), epidermal growth factor receptor (EGFR), epithelial cell adhesion molecule (EpCAM), human epidermal growth factor receptor 2 (HER2), vascular endothelial growth factor (VEGF), and several integrins, as targets for tumor imaging has been successfully demonstrated in both preclinical and clinical settings [2–10]. The gene discussed is CEACAM5; the disease is neoplasm.