Epidermal growth factor receptor (EGF-R) in human middle ear cholesteatoma: an analysis of protein production and gene expression.

Abstract

Previous studies have shown an altered epithelial cell proliferation in middle ear cholesteatoma, reporting an aberrant expression of epidermal growth factor receptor (EGF-R) glycoprotein by immunohistochemistry. In this study, we quantified the presence of EGF-R using enzyme-linked immunosorbent assays (ELISAs) on tissue extracts, as well as the EGF-R gene expression by in situ hybridization on frozen sections. Human skin obtained from the external ear canal was used as control. The amounts of EGF-R glycoprotein in cholesteatoma were very similar to those in human skin. Human skin showed EGF-R messenger RNA (mRNA) only in the basal layer. A higher percentage of cells hybridized for the anti-sense probes EGF-R was found in cholesteatoma epithelium. Furthermore, we could find suprabasal cells with EGF-R mRNA. Our results confirm that the abnormal growth of cholesteatoma epithelium is reflected in an aberrant expression of EGF receptor.