Clinically, excellent targeting of MTC has been found with radiolabeled anti-CEA antibodies, and antitumor effects have been achieved with 131I-labelled anti-CEA antibodies, suggesting a high potential of pretargeting for diagnostic and theranostic applications in MTC patients [68,69,70,71,72]. Here, CEACAM5 is linked to medullary thyroid gland carcinoma.