Immunohistological studies of medullary thyroid carcinoma and C cell hyperplasia.

A series of 59 thyroidal C cell neoplasms was studied by immunoperoxidase histology. These neoplasms included human medullary thyroid carcinoma and C cell hyperplasia and rat medullary thyroid carcinoma. In addition to calcitonin, the tumors were studied by immunohistology for the presence of beta-endorphin, ACTH, and somatostain. All but one of the neoplasms were positive for calcitonin, 25 of 31 were positive for beta-endorphin, 12 of 18 were positive for ACTH, and 9 of 19 were positive for somatostatin immunoreactivity. Many tissues contained all 4 peptides, and in some sections these peptide immunoreactivities seemed to be present in the same cells. These studies suggest that there is a relationship in these tumors among the 4 peptides studied, but the basis of this relationship is not clear.