Carcinoembryonic antigen (CEA) is an antigen that is overexpressed in colorectal cancers and is considered a suitable target for its treatment. Uppsala University discussed research in the development of the lutetium-177-radiolabeled anti-CEA hT84.66-M5A monoclonal antibody (MAb) 177Lu-DOTA-M5A for the treatment of colorectal cancers and its combination studies with the HSP90 inhibitor onalespib.