TELOMERASE ACTIVITY IN 144 BRAIN-TUMORS

Unlimited proliferation in immortalized cells is believed to be highly dependent on the activity of telomerase, a ribonucleoprotein that syn thesizes telomeric repeats onto chromosome ends. Using a polymerase ch ain reaction-based telomeric repeat amplification protocol (TRAP) assa y, we analysed telomerase activity in 99 benign and 45 malignant brain tumours. The TRAP assay results were quantitated by normalizing the t elomerase activity of each specimen to that of human glioma cell line T98G to obtain the relative telomerase activity. Telomerase activity w as also assessed visually from the autoradiograms as being positive or negative. One hundred and sixteen tumours with negative telomerase ac tivity had null relative telomerase activity, whereas 28 tumours with positive telomerase activity had relative telomerase activities of 12- 84.3% (mean 0% vs 36.1 +/- 19.3%, P < 0.0001). Thus, quantification of telomerase activity confirmed the results of the visual evaluation of telomerase activity on autoradiograms. Based on the assessment, malig nant brain tumours had a higher positive rate of telomerase activity t han benign tumours (57.8% vs 2.0%, P < 0.001). These data indicate tha t positive telomerase activity is strongly associated with malignant b rain tumours and is rather rare in benign tumours, such as neurinomas or meningiomas.