The Importance of Ki-67, Ck-6 and Ck-16 Expression in the Evaluation of the Destructive Effect and Hyper Proliferative Capacity of Cholesteatoma
Objective: Cholesteatoma, with its hyperproliferative feature and destructive pathogenesis, causes bone destruction of the middle ear structures and its surroundings. We aimed to investigate the expression of Ki-67, cytokeratin-6 (CK-6) and cytokeratin-16 (CK-16) in acquired and recurrent cholesteatoma and to correlate them with bone destructive capacity. Materials and Methods: The study was performed as a prospective immunohistochemical study using cholesteatoma tissue (n=45) and external auditory canal skin (n=10) collected during tympanoplasty operation. The findings were recorded considering whether the cholesteatoma was recurrent or not, the extent of cholesteatoma during the operation, ossicular damage and the presence of complications. The patients were divided into 4 groups: Complicated cholesteatoma, recurrent cholesteatoma, uncomplicated cholesteatoma and external auditory canal skin as the control group. Groups were compared in terms of Ki-67 expression level, CK-6 and CK-16 staining patterns. Results: In all groups with cholesteatoma, Ki-67 index was found to be significantly higher than the control group. In addition, the Ki-67 index was found to be significantly higher in the complicated and recurrent cholesteatoma groups compared to the uncomplicated group (p=0.015 and p=0.001, respectively). While CK-6 showed only suprabasal staining on the skin of the external auditory canal, it showed a full-coat staining pattern in cholesteatoma. When the groups with cholesteatoma were compared in terms of CK-16 staining pattern, the only significant result was higher full-thickness staining rates in the recurrent cholesteatoma group compared to the uncomplicated cholesteatoma group (p=0.022) Conclusion: Ki-67 index has been shown to be an important pathological parameter in evaluating the aggressive behavior of cholesteatoma. In addition, our study is the first to show the significant relationship of Ki-67 and CK-16 with recurrent cholesteatomas.