GRPR and neoplasm: Only the radioiodinated heterodimer 125I-BO530, which combines a PSMA-targeting urea-based inhibitor with a GRPR antagonist (RM26), linked via a PEG2 linker, demonstrated high affinity for both receptors and high tumor uptake (~30–35% ID/g at 3 h), which was sustained up to 24 h.