Immunohistochemical study of medullary thyroid carcinoma: relationship of clinical features to prognostic factors in 36 patients.

Abstract

AbstractThis study was designed to identify 11 different antigens including calcitonin (CT), calcitonin gene‐related peptide (CGRP), gastrin‐releasing peptide (GRP), and carcinoembryonic antigen (CEA), in the tumors of 36 patients with medullary thyroid carcinoma (MTC) using immunoperoxidase staining techniques. In addition, clinical features of MTC patients were compared with the immunohistochemical findings to establish factors influencing prognosis. MTC was found to contain various products in many patients and CT and CEA were positive in all patients. CGRP and GRP showed positive staining in 96.6% and 82.9% of MTC patients, respectively, suggesting that CGRP and GRP are novel tumor markers for MTC. In tumor cells, CT, CGRP, and GRP were often revealed in identical cells. Familial patients showed more multiple substances than sporadic patients. In the 2 inoperable patients with extremely aggressive progression, tumors showed undifferentiated histology and poor staining for peptide hormones, suggesting that specific qualities such as neuroendocrine tumor had been lost. These 2 patients particularly revealed an inverse relationship between CT and CEA distribution such that small amounts of CT were present in cells which have homogenous staining for CEA. This study suggests that CGRP and GRP, in addition to CT and CEA, may be a histologically potential tumor marker for MTC. CT and CEA may be possible markers for differentiating patients with high malignancy from those with ordinary malignancy.