Cycline-dependent kinase inhibitor, p27 (KIP1), is associated with cholesteatoma

Objective: Cyclin-dependent kinases (CDKis) can arrest the cell cycle, whic h in turn inhibits the cell proliferation. P27 (KIP1) is a CDKi and acts as a tumor suppressor gene. In this study, we aimed to investigate the role o f p27 CDKi in cholesteatoma, a disease characterized by the presence of hyp erproliferative squamous epithelium. Study Design: Immunohistochemical stai ning of 15 cholesteatoma and 18 control ear canal skin samples, which were taken intraoperatively, was performed for p27 positivity, Methods: The mono clonal antibodies to p27 were used for immunohistochemical staining of the sections. The streptavidin-biotin horseradish method was used. The number o f cells staining positive for p27 was calculated, and the intensity of p27 positivity was graded. Results: P27 positivity was obtained in 9 (50%) of 1 8 skin tissues. In the cholesteatoma tissues, p27 positivity was found only in 2 (13.3%) tissue samples. The difference between the groups were statis tically significant (P = .03). The mean numbers of p27 positivity were 11.8 +/- 15.5 and 1.4 +/- 3.8 (mean +/- standard deviation) in the skin and cho lesteatoma samples, respectively. This difference was also statistically si gnificant (P = .02), The p27 results of primary and secondary cholesteatoma samples were not significantly different (P = .3), The results of p27 were not related to the gender of the patients (P = .8), Conclusion: P27 is inv olved directly or indirectly in the occurrence of cholesteatoma, Alteration s of p27 levels in keratinocytes can influence the proliferative state of t he keratinocytes. Altered p27 levels in cholesteatoma may suggest a molecul ar pathology in cholesteatoma, The search for significance of CDKis seems p romising to better understand the pathogenesis of cholesteatoma.