Occurrence of calcitonin, somatostatin-like immunoreactivity, and carcinoembryonic antigen in two sisters suffering from familial thyroid medullary carcinoma.

The presence of calcitonin, somatostatin-like immunoreactivity and carcinoembryonic antigen in tumor tissues (surgically obtained) and identified by the peroxidase-antiperoxidase technique, is reported in two sisters suffering from familial thyroid medullary carcinoma. C-cell hyperplasia occurred in both individuals. Preoperatively, both patients had elevated calcitonin serum levels (290 pM, 991.8 ng/l), and carcinoembryonic antigen (60 micrograms/l). No ACTH or thyroglobulin immunoreactivity could be found in the tumor tissue. After thyroidectomy, 131I-treatment and percutaneous radiation, somatostatin-like immunoreactivity and carcinoembryonic antigen plasma levels were in the normal range, whereas calcitonin was still elevated. It is proposed that calcitonin, somatostatin, and carcinoembryonic antigen are produced by the thyroid medullary carcinoma.