Nucleoplasm Staining Patterns and Cell Cycle-associated Expression of Ki-67 in Middle Ear Cholesteatoma

Objectives: To compare Ki-67 expression patterns in middle ear cholesteatoma with the corresponding retroauricular and external auditory canal skins, and to determine the cell cycle-dependent localization of Ki-67.

Material And Methods: MIB-1 monoclonal antibody was used for comparative assessment of proliferative activity of middle ear cholesteatoma, external auditory canal skin, and retroauricular skin samples on formalin-fixed paraffin-embedded tissue sections. Primary keratinocytes from cholesteatoma tissue were isolated and subjected to kinetic analysis of the cell cycle.

Results: Higher proliferative activity was established in cholesteatoma in comparison with retroauricular and external auditory canal skins. Three different staining patterns have been described. Kinetic analysis revealed continuous expression of Ki-67 during all active phases of the cell cycle and remained "silent" in resting cells.

Conclusion: The established correlation between the staining patterns and cell cycle-associated expression of Ki-67 specifies Ki-67 as a reliable and stable marker of proliferation for middle ear cholesteatoma.