Telomerase activity in microdissected human gliomas

Future improvements in the diagnosis and treatment of human gliomas might r ely on obtaining more specific information concerning the biologic characte ristics of individual tumor cells. Telomerase, a ribonucleoprotein that syn thesizes telomeres, has been reported to be expressed in a majority of huma n tumors, including several subtypes of brain tumor. We hypothesized that a quantitative assay for telomerase activity, combined with selective microd issection of tumor or normal brain cells, might reveal telomerase gain-of-f unction to be important in the pathogenesis of gliomas and that telomerase levels might have prognostic significance. We used tissue microdissection f or selective analysis of tumor cells obtained from eight patients with glio ma, one with a meningioma, and one with a primary B-cell lymphoma of the ce ntral nervous system. Normal brain tissue microdissected from another patie nt was used as a control. Telomerase activity was screened by an electropho retic method and then assayed by a quantitative ELISA method. All of the ei ght gliomas had positive telomerase activity, as did the lymphoma The menin gioma and normal brain were negative. Quantitative analysis of telomerase a ctivity did not correlate with tumor grade nor predict outcome. Selective t issue microdissection, combined with qualitative and quantitative telomeras e assays, permits rapid and reliable detection of telomerase activity in di verse brain tumor tissues. These preliminary findings suggest that telomera se reactivation is a frequent event in glioma tumorigenesis that can be sen sitively and specifically detected in gliomas of all histologic grades. Fur thermore, specific detection of telomerase reactivation represents another mechanism by which tumor formation and progression might become the target of novel therapeutics.