Expression of epidermal growth factor receptor in human middle ear cholesteatoma

Middle ear cholesteatoma is destructive to auditory ossicles and temporal bone, and treatment usually includes surgical removal of all epithelial content in the tympanomastoid cavity. Epidermal growth factor receptor (EGFR) is a 170 kd to 180 kd transmembrane glycoprotein and its distribution density is related to the ability of the keratinocytes to differentiate and their state of differentiation. We used the avidin-biotin complex technique and EGFR monoclonal antibody to evaluate the expression of EGFR in 29 cases of cholesteatoma and 34 samples of normal postauricular skin. Of patients with cholesteatoma, 79% (23 cases) had EGFR-positive cells in the basal layer, 66% (19 cases) in the parabasal layer, and 62% (18 cases) in the upper layer of the epithelial tissue. Among patients with normal postauricular skin, 85% (29 cases) had EGFR-positive cells in the basal layer, 79% (27 cases) in the parabasal layer, and 79% (27 cases) in the upper layer of the epithelial tissue. No statistical difference in EGFR expression between each layer of cholesteatoma and postauricular skin was noted. However, there was an intensity gradient of positive EGFR immunoreactivity from the basal to the higher layers in cholesteatoma. Our results showed that the distribution of EGFR in middle ear cholesteatoma is not deranged, but is similar to that in normal skin tissue.