Immunohistochemical studies on the localization of fibronectin in human thyroid neoplastic tissues.

Fibronectin (FN) has been considered to be involved in the malignant transformation of cells. It was thus of interest to morphologically study the cell surface distribution of FN in various types of thyroid neoplasms employing immunohistochemical techniques. Immunohistochemical staining using the specific anti-human FN antibody was performed by the avidin-biotin-peroxidase complex procedure. Compared to the staining pattern of normal thyroid tissues (control), differences in staining in malignant thyroid lesions and even in fetal and embryonal adenomas were evident, often on the lateral and basal aspects of the cell membrane. Colloid adenomas, however, showed FN staining on the basement membrane, basically similar to the controls. Moreover, in thyroid carcinoma, different staining patterns relating to each of the histological types were observed. The present investigation demonstrates the heterogeneity of the thyroid neoplasms in terms of FN binding.