DPI-4452 is a CAIX-targeting cyclic peptide with a DOTA cage, and can be chelated with radionuclide for CAIX-expressing tumor PET-CT imaging and study. DPI-4452 specifically and selectively binds CAIX without interaction with an in vitro off-target receptor panel of 55 targets (IC50 for recombinant hCAIX: 130 nM). Radiolabeled DPI-4452 inhibits tumor growth in HT-29 and SK-RC-52 xenograft mouse models[1]. DPI-4452 can be used for the synthesis/research of Radionuclide-Drug Conjugates (RDCs).