ABSTRACT
Growth factors are polypeptide molecules that regulate cell growth and function by binding with high affinity to specific receptor molecules in the plasma membrane and stimulating receptor mediated action of intracellular signal transduction pathway.Epidermal growth factor(EGF) and their receptors(EGFR) regulate normal cellular growth, proliferation, and differentiation of various cells in vivo and in tissue cultures. And also may contribute directly to oncogenesis.Overexpression of EGFR and autocrine stimulation of growth involving this receptor system has been identified in several types of human neoplasia. There is evidence that the EGF and receptor system is involved in the regulation of follicular cell growth in the thyroid gland especially with immunohistochemical technic. But there was a challenge about the validity of previously performed immunohistochemical studies.In the study we investigated the relationship between EGFR mRNA expression and tumorigenesis by rapid in situ hybridization method. Formalin-fixed, paraffin embedded tissue sections of 10 normal, 17 nodular hyperplasia, 6 follicular adenoma, and 15 papillary cancer were examined. The results were as follows:1) EGFR mRNA positivity were 20%(2/10) in normal thyroid, 70%(12/17) in nodular hyperplasia, and 100% in follicular adenoma and papillary cancer.2) There was a significantly increased EGFR mRNA expression in papillary cancer compare to normal and nodular hyperplasia(p<0.05). But no difference was found with papillary cancer and follicular adenoma.3) There was a significantly increased EGFR mRNA expression in follicular adenoma compare to normal (p<0.05). But no difference was found with follicular adenoma and nodular hyperplasia. These results suggest that an overexpression of EGFR mRNA may play an important role in the tumorigenesis of thyroid tissue.