HORMONAL STUDY OF A HUMAN MIXED FOLLICULAR AND MEDULLARY-THYROID CARCINOMA

We studied the hormonal secretion of a human mixed follicular and medu llary carcinoma. Thyroglobulin (Tg) secretion, especially by large cel ls and sometimes by small ones, was visualized with immunoenzymatic st aining. Calcitonin (CT) was produced by small spindle-shaped cells. Mo reover, immunofluorescence double staining performed on the resected t hyroid tissue showed the secretion of both Tg and CT in a small number of cells. The cells lost their hormonal secretion after 2 months of c ulture. Hormonal secretion was modulated by different additives in the medium. Tg secretion was induced when TSH was added to the culture me dium; the maximal effect was produced with the addition of 1 mU TSH/ml and 1 muM cortisol, which potentiated the effect of TSH on Tg product ion. A durable Tg secretion was obtained by embedding the cells in Eng elbretch-Hohn-Swarn (EHS) tumour matrix. The CT production was reinduc ed by the addition of 4 mm Ca2+, 1 muM glucagon and 1 muM cortisol to the culture medium. These findings show that different cells are found in a mixed follicular and medullary carcinoma, some of which can secr ete both CT and Tg. They can remain differentiated for a long period a fter being embedded in EHS tumour matrix with Ca2+ and hormonal compon ents.