Telomerase activity in gliomas with the use of non-radioisotopic and semi-quantitative procedure for terminal repeat amplification protocol.

To study the role of telomerase in the pathogenesis of different grades and subtype of gliomas, telomerase activity in 31 gliomas was assessed with the use of non-radioisotopic and semi-quantitative procedures for the terminal repeat amplification protocol in this study. Among the samples were 17 glioblastoma multiformes (GBMs); 4 anaplastic astrocytomas (AAs); 5 astrocytomas (ASs); 1 ependymoblastoma (EPB); 2 ependymomas (EPs); 1 oligodendroglioma (OG) and 1 medulloblastoma (MB). Postive telomerase activity was detected in 9 of 17 GBMs (53%), 1 of 4 AAs (25%), 1 of 5 ASs (20%), 1 of 1 EPB (100%), and in positive controls, T 98G and KE-1. Weakly positive activity was detected in 2 of 3 AAs (66%) and 2 of 5 ASs (40%). No telomerase activity was detected in 8 of 17 GBMs (47%), 1 of 4 AAs (25%), 2 of 5 AS (40%), 2 of 2 (100%) EPs, 1 of 1 OG (100%), 1 of 1 MB (100%) and normal brain tissue. We defined telomerase expression as positive and weakly positive cases. The percentage of telomerase activity expression in gliomas tended to correlate with tumour grade in spite of histopathology of tumours. These results indicated that the telomerase activity of gliomas may be used as a tumour marker and that the activation of telomerase should correlate with initiation and malignant progression of gliomas. In addition, non-radioisotopic and semi-quantitative procedure for the terminal repeat amplification protocol appears to be the most suitable to detect telomerase activity expression in small neurosurgical specimens.