Keratinocytes in cholesteatoma demonstrate uncoordinated hyperproliferation, migration, and invasion properties. There is a controversy regarding the impact of Ki-67 and telomerase activities on cellular proliferation in cholesteatoma. We studied expression of Ki-67 protein and telomerase activity in cholesteatoma and its relationship with clinical findings.
The expression level of Ki-67 protein was examined by immunohistochemical analysis of 51 cholesteatomas and 6 skin tissues obtained from patients during ear surgery. Telomerase activity was determined in 23 samples of cholesteatomas and 6 skin samples by polymerase chain reaction-based telomeric-repeat amplification protocol assay.
The presence of Ki-67 protein was observed in 21 (41.2%) of 51 samples of acquired cholesteatoma. The average Ki-67 labeling index in the cholesteatoma group was 28.9 ± 9.2 and was higher than that in the skin group (18.2 ± 6.1). Telomerase activity was detected in 2 (8.7%) of 23 samples of cholesteatoma (21 of them were Ki-67 staining positive and 2, negative) and in 3 (50%) of 6 of control skin samples (p < 0.05).
This study showed increased expression of Ki-67 in cholesteatoma, whereas there was no significant difference in rate of Ki-67 positive staining between skin and cholesteatoma (p = 0.066). Telomerase activation is a rare event in cholesteatoma. We assume that the absence of telomerase may lead to generation dysfunctional telomeres what in turn may impair the proliferative capacity of cholesteatoma.
*Departments of Otolaryngology, †Molecular Medicine, and ‡Immunopathology, Medical University of Gdansk, Gdansk, Poland
Address correspondence and reprint requests to Dr. Jerzy Kuczkowski, Department of Otolaryngology, Medical University of Gdansk, ul. Debinki 7, 80-211 Gdansk, Poland; E-mail: email@example.com