Immunohistochemical demonstration of epidermal growth-factor receptors in normal, benign and malignant thyroid tissues

Human epidermal growth factor receptor (EGF-receptor) has been detected immunohistochemically in normal, benign and malignant human thyroid tissues. With a monoclonal antibody for EGF-receptor and avidin-biotin-peroxidase complex (ABC), the expression of EGF-receptor was evaluated in paraffin-embedded sections. Carcinomas of the thyroid showed a moderate to intense staining for EGF-receptor in most cases. Apical cell surface and cytoplasmic staining was the most common pattern of immunoreactivity. Adenomas showed a variable positivity in the cytoplasm of th tumor cells, and their apical cell surface staining was generally negative to borderline. The follicular cells in Hashimoto's thyroiditis showed a weak to moderate cytoplasmic staining, but those in Graves' disease and normal thyroids showed an essentially negative cytoplasmic staining. Apical cell surface staining was essentially negative or borderline in these benign lesions. There were no significant correlations between EGF-receptor expression and tumor size, degree of invasion or cervical metastases in the thyroid carcinomas. The apical surface expression of EGF-receptor was characteristic to thyroid carcinomas and this feature may be useful in the differentiation of thyroid carcinomas from benign thyroid lesions.