GRPR and neoplasm: The tumor uptake of both radioligands was found to be GRPR-specific at 4 h pi by the significantly reduced uptake seen in the block-groups of animals ([111In]In-AU-RM26-M2: 7 ± 2%IA/g in controls vs. 0.9 ± 0.4%IA/g in blocks; p < 0.0001 and [111In]In-AU-RM26-M4: 15 ± 5%IA/g in controls vs. 1.4 ± 0.6%IA/g in blocks; p < 0.0001) and a similar trend was also evident in the GRPR-rich mouse pancreas.