Background:of this study was to determine the proliferative capacity in certain layers of the cholesteatoma epithelium and normal skin.

Material/Methods:Cholesteatoma and skin were obtained during ear surgical procedures. The number of PCNA- and Ki-67-positive cells were counted within each of three microscopic fields at a magnification of ×400. Fourteen normal skin specimens collected from the retroauricular area were used as controls.

Results:The skin specimens were found to have a lower proliferative capacity than the cholesteatoma epithelium. This activity was mainly observed in the cell nuclei of the basal layer of the epidermis. The percentage of PCNA-positive cells was 23% in the epidermis and 45.7% in the cholesteatoma epithelium. Immunohistochemical investigation of the epidermis revealed 7% Ki-67-positive cells, mainly located in the basal layer of the epidermis. The presence of Ki-67 antigen in the cell nuclei was determined in the parabasal layer of the cholesteatoma epithelium and stroma. Ki-67-positive cells made up 22% of the cholesteatoma epithelium, compared with 7% in the skin.

Conclusions:Proliferative activity is mainly observed in the basal and suprabasal layers of the cholesteatoma epithelium. The proliferative capacity of the cholesteatoma epithelium is different in the various areas of the epithelium and does not depend on its thickness.

Keywords: Biological Markers - analysis, Cholesteatoma, Middle Ear - pathology, Epidermis - pathology, Ki-67 Antigen - metabolism, Proliferating Cell Nuclear Antigen - metabolism