Tumor uptake of 111In-labeled biotin peaked at 3.3% ID/g at 15 minutes p.i. Tracer clearance from the blood and normal organs was extremely rapid with a tumor-to-blood ratio of about 20:1 at 24 h p.i., thus making it a promising strategy for the imaging of CEA-positive cancers. Here, CEACAM5 is linked to cancer.