Sigma-2 ligands preferentially bind to cancer as opposed to normal tissues. (A): Single cell suspensions were prepared from liver, lung, pancreas, brain, kidney, spleen and pancreatic tumors (panc-02 bearing mice). Single cell suspensions were incubated for 1 hour with KO5-138 (a fluorescent labeled sigma-2 receptor ligand, at 50 nM (thin doted line) or 100 nM (thick solid line) of ligand, or left unstained (thin solid line). FACS histograms demonstrate 100 fold more florescence in tumors compared to normal tissues. (B): Human pancreatic cancer lines (CFPAC-1, Panc-1, AsPC-1) demonstrate similar high degree of sigma-2 ligand binding to when compared to our murine model (Panc-02). Fluorescein signal peaks were shown in unstained control (thin solid line), 50 nM of ligand (dotted line), or 100 nM of ligand (thick solid line). The experiment was repeated twice with identical results. (C): Representative Micro PET/CT images of pancreas adenocarcinoma (Panc-02) bearing C57BL/6 mice administered RHM-4 (18F-labled sigma-2 ligand). The tumor indicated by arrows was approximately 1 cm3. The additional hot spot represents metastatic tumor in a regional lymph node.