COEXPRESSION OF THE GENES ENCODING TRANSFORMING GROWTH FACTOR-ALPHA AND ITS RECEPTOR IN PAPILLARY CARCINOMAS OF THE THYROID

Transforming growth factor‐α (TGF‐α) is frequently co expressed with its receptor, epidermal growth factor receptor (EGF‐R), in several types of carcinoma and sarcoma. It is believed that this results in an autocrine stimulation of tumor growth in these tumors. We have found that TGF‐α and EGF‐R/c‐erbB RNAs were co‐expressed at significantly higher levels in papillary thyroid carcinomas and their lymph‐node metastases than in non‐neoplastic thyroid tissues. We also observed a low level of expression of RNA specific for insulin‐like growth factor I in these tumors, which was highest in a lymphnode metastasis. Autocrine stimulation by TGF‐α may thus be a common feature of papillary carcinomas of the thyroid. Since EGF is known to induce proliferation and dedifferentiation of normal thyroid cells in culture, TGF‐α and its receptor may play an important role in thyroid carcinogenesis. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company