[Markers of epidermal proliferation in middle ear cholesteatoma]

Middle ear cholesteatoma is characterized by the presence in the middle ear cavity of a stratified squamous epithelium with keratin deposits which by constant proliferation leads to extensive bone destruction. The goal of this study was to evaluate, by immunohistochemical study, the expression of epithelial markers of proliferation--Ki-67 and PCNA in the matrix of cholesteatoma. The materials used in this study were 16 acquired cholesteatoma tissues collected from patients in the age 6-17 years during surgery. The specimens from the skin of the external ear canal were employed as the control. In the immunohistochemical specimens staining intensity and distribution of Ki67 and PCNA positive cells in various layers of the epithelium were assessed in three stages scale. The results were compared to the clinical parameters such as--type of cholesteatoma (pars flaccida or tensa), presence of ear discharge, degree of ossicular destruction and involvement of attic and mastoid. In the cholesteatoma matrix Ki-67 and PCNA positive cells were present in basal and suprabasal cell layers and also more superior layers, unlike the control skin were only basal cells show positive staining. The number of positive cells and intensity of staining was also greater in the cholesteatoma matrix than in skin of external auditory meatus. No correlation was found between results of immunohistochemical examination and clinical parameters.