Correlation of clinical features and telomerase activity in human gliomas.

Telomerase is a ribonucleoprotein containing an RNA template that synthesizes telomeric DNA. The expression of telomerase activity is concomitant with the attainment of immortality in tumor tissues and cells. In this report, we analyzed telomerase activity in 39 human gliomas with different histological, and in 10 meningiomas, 3 neurinomas, and 2 normal brain tissues by using a polymerase chain reaction (PCR)-based telomeric repeat amplification protocol (TRAP) assay. Telomerase activity was detectable in almost all of the gliomas (36 of 39), but not in any of the meningiomas, neurinomas, or normal brain tissues. In addition, we also analyzed the level of telomerase activity in the 36 gliomas with positive telomerase activity. The relative telomerase activity of the glioma showed a clear association with the pathological grade of glioma; i.e., most of the tumors with high telomerase activity were pathologically of high grade. And also the relative level of telomerase activity could be correlated with the survival time of the patients. These results suggest that the level of telomerase activity in brain tumors is a diagnostic marker indicating the prognosis of the patient as well as the malignant potential of the tumor.