Telomerase activity and cell proliferation index in cholesteatoma

Telomerase activity was expressed in cholesteatomas, and cellular proliferation was significantly higher in cases where the telomerase activity was positive. Telomerase activity was also closely related with cellular proliferation in chronic hyperproliferating tissues such as cholesteatomas.

Telomerase activity is detected in most malignant tumors and is also known to have a close relationship with cell proliferation. Cholesteatoma shows cellular hyperproliferation. We studied telomerase activity in cholesteatoma and its relationship with cellular proliferation and clinical findings.

Cholesteatoma tissue was obtained from 40 patients during middle ear surgery. Telomerase activity was measured using a telomeric repeat amplification protocol method. As a cellular proliferation index, expression of Ki-67 was measured by means of immunohistochemical staining. Posterior auricular skin was used as a control. Telomerase activity was compared with Ki-67 expression. Clinical features such as hearing loss, the extension of cholesteatoma, the degree of bone destruction and the cause of cholesteatomas were compared with telomerase activity and the cellular proliferation index.

Telomerase activity was positive in 21/40 cholesteatomas (52.5%), but absent in the control group. The average Ki-67 labeling index in the cholesteatoma group was 32.84+/-10.13, higher than that in the control group (21.83+/-7.76) (p<0.05). The average Ki-67 labeling indices of the 21 telomerase activity-positive and 19 telomerase activity-negative cholesteatomas were 37.76+/-8.53 and 27.39+/-9.06, respectively. The Ki-67 labeling index was significantly higher in telomerase-positive cholesteatomas (p<0.05). The clinical features did not show a relationship with either telomerase activity or the cellular proliferation index.