HSF4 and medullary thyroid gland carcinoma: This was the case (Table 1, CLN number 19 and 20) of the patient harboring metastatic MTC and characterized by elevated level of serum calcitonin in which FNAB-C indicated metastatic PTC, while on the contrary both FNAB-Tgp and FNAB-Tgm were negative, and FNAB-CTm positive.