GRPR and prostate cancer: The bombesin agonist 177Lu AMBA demonstrated potential therapeutic effectiveness in several preclinical prostate cancer tumor models [65], but a phase I dose escalation study in patients with mCRPC was stopped due to severe adverse effects due to GRPR stimulation at the therapeutic levels of administered 177Lu AMBA [66] and most other GRPR targeted radiotherapeutic agonists have encountered similar safety problems.