[Immunohistochemical analysis of malignant tumors of the thyroid gland using 6 relevant markers]

The results of immunohistochemical study of malignant thyroid tumours using six markers-thyroglobulin (TGB), keratin, carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), calcitonin and leucocyte common antigen (LCA)-are presented. Thirty-three cases of thyroid carcinomas were studied: 11 papillary, 8 follicular, 7 medullary and 7 anaplastic carcinomas. All cases of papillary and follicular tumours showed positive reaction with TGB and 4 papillary and 3 follicular carcinomas reacted with CEA also. 100% reactivity with calcitonin and CEA were observed in the medullary carcinoma group, while anaplastic carcinomas revealed TGB (one case), CEA (two) and EMA (three) reactivity. None of the studied tumours responded to LCA. TGB and calcitonin proved to be useful in distinguishing tumours originating in follicular cells from those originating in parafollicular cells and, along with LCA, enabled discrimination of anaplastic carcinomas from medullary carcinomas and malignant lymphomas. CEA can be only used as an auxiliary marker in cases of medullary carcinoma, while EMA and high molecular weight keratins did not prove to be reliable markers for analysis of malignant thyroid tumours.