Immunohistochemistry (ELISON method, see Figure 4) showed: in the medullary carcinoma area: PCK (+), CEA (+), CT (focal cytoplasmic weak +), INSM1 (+), Syn (+), CgA (+), Galectin-3 (-), TG (-), CK19 (-), Ki-67 (+, 3%). Here, CEACAM5 is linked to medullary thyroid gland carcinoma.