Expression patterns of Ki-67 and telomerase activity in middle ear cholesteatoma.
BACKGROUND
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Kuczkowski
Jerzy
J
Department of Otolaryngology, Medical University of Gdansk, Gdansk, Poland. jerzyk@amg.gda.pl
Pawelczyk
Tadeusz
T
Bakowska
Alicja
A
Narozny
Waldemar
W
Mikaszewski
Boguslaw
B
D000293:Adolescent; D000328:Adult; D049109:Cell Proliferation; D002648:Child; D002675:Child, Preschool; D018424:Cholesteatoma, Middle Ear / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D017931:DNA Primers / Q000235:genetics; D042622:DNA Repeat Expansion / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D019394:Ki-67 Antigen / Q000235:genetics*; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D019098:Telomerase / Q000235:genetics* / Q000502:physiology
D017931:DNA Primers; D019394:Ki-67 Antigen; D019098:Telomerase