Localization of proliferating cell nuclear antigen in aural cholesteatoma

Middle ear cholesteatoma is not a genuine tumor but has a remarkable proliferative activity which causes serious destruction of the mastoid bone. In the present study, we used immunohistochemistry with antiproliferating cell nuclear antigen (PCNA) antibody on cholesteatomatous tissues to evaluate the localization of PCNA, as it has been said that PCNA is a very available protein for showing cell proliferative activity. Moderately concentrated PCNA was demonstrated within the germinal basal layer cells of the cholesteatomatous epithelium in three of eight surgical specimens. Furthermore, in one case of very active osteolytic cholesteatoma, PCNA activity was demonstrated in the mesenchymal cells, probably fibroblast-like cells, in direct contact to the destroying mastoid bone lesions. Although the etiology and histopathology of the invasive and proliferative activity of middle ear cholesteatomatous tissues are unclear, this observation suggests that immunohistopathological examination using PCNA antibody might be a useful tool for evaluating bone resorption activity and for establishing the prognosis of various types of cholesteatoma.