CDH17 and adenocarcinoma: These encouraging data not only support the further preclinical exploration of the radioimmunoconjugate in other CDH17-expressing adenocarcinomas (e.g., gastric adenocarcinoma) but also suggest that [89Zr]Zr-DFO-D2101 could have a role to play in the clinic as a companion theranostic imaging agent for CDH17-targeted therapies or (if labeled with a different radionuclide) a radioimmunotherapeutic.