g. an additional 18F-FDG PET for the evaluation of tumor dedifferentiation; in case of FDG-avid, non-PSMA-avid lesions, 18F-FDG PET imaging might be the superior modality for tumor characterization and, moreover, the application of PSMA-directed therapies should be critically discussed (34, 35). The gene discussed is FOLH1; the disease is neoplasm.