TELOMERASE ACTIVITY IN HUMAN GLIOMAS

OBJECTIVE: Telomerase activity, which is undetectable in most mature n ormal tissues, has been identified in many types of human cancers, inc luding neuroblastomas and oligodendrogliomas. These findings suggest t hat a novel mechanism in addition to activation of oncogenes and inact ivation of tumor suppressor genes may play an important role in tumori genesis. The goal of the present study was to assess and correlate the telomerase activity in astrocytic gliomas of different grades. METHOD S: Telomere repeat amplification protocol and Southern blot hybridizat ion with telomere-specific probes were used to detect telomerase activ ity and to measure terminal restriction fragment length, respectively. RESULTS: Telomerase activity was detected in 3 of 9 (33%) low-grade a strocytomas (World Health Organization Grade II), 5 of 11 (45%) anapla stic astrocytomas (World Health Organization Grade III), 36 of 41 (89% ) glioblastomas multiforme (World Health Organization Grade IV), 3 of 4 (75%) oligodendrogliomas, and none of 4 normal brain specimens. CONC LUSION: We demonstrated that telomerase activity is absent in normal b rain tissues while present in most glioma samples (72%). The frequency of such activity increases with malignancy. These results suggest tha t telomerase activity may be used as a tumor marker and that the activ ation of telomerase may correlate with initiation and malignant progre ssion of astrocytic tumors.