SST and neoplasm: The observation that a variety of tumours overexpress natural peptide receptors has served as the molecular basis for the clinical use of radiolabelled peptides in peptide receptor radionuclide therapy (PRRT) (de Jong and Krenning, 2002), a strategy that has already proved to be successful in detecting and treating somatostatin receptor-positive tumours using radioactive somatostatin or its analogues (Froidevaux and Eberle, 2002).