However, although both compounds revealed a higher CCK-2R affinity compared to [177Lu]Lu-(R)-DOTAGA-rhCCK-16 (IC50 = 20.4 ± 2.7 nM; activity levels in the tumor: 18.0 ± 0.7%ID/g [8]), significantly lower activity levels were found in the tumor. This evidence concerns the gene CCKBR and neoplasm.