Differential telomerase activity, expression of the telomerase catalytic sub-unit and telomerase-RNA in ovarian tumors

Telomerase activity has been found in a variety of malignant tumors but onl y rarely in benign tumors or normal tissues. In this study, we investigated telomerase activation in 37 ovarian tumors, including benign, borderline a nd malignant neoplasms. Telomerase activity was detected using the telomeri c repeat amplification protocol (TRAP) in 13/16 ovarian carcinomas, 9/10 bo rderline tumors and 3/11 cystadenomas/fibromas. mRNA expression of the puta tive human telomerase catalytic sub-unit gene (hTERT) was detected by RT-PC R in 14/15 ovarian carcinomas, 8/10 borderline tumors and 4/11 cystadenomas /fibromas. In site hybridization was performed to evaluate telomerase-RNA ( hTR) expression in the corresponding paraffin-embedded tumors. Variable exp ression levels of hTR were found over neoplastic tumor cells. The highest l evels of hTR expression were found predominantly in ovarian carcinomas. Alt hough the amount of telomerase activity varied, significantly high levels o f telomerase activity were found predominantly in ovarian carcinomas. hTERT mRNA expression was closely associated with telomerase activity. These fin dings suggest that up regulation of hTERT and hTR is important for telomera se activation during malignant-tumor progression. Telomerase activation mig ht therefore be a valuable diagnostic parameter that could help to identify potentially progressive lesions. However, the diagnostic and therapeutic i mplications of telomerase activation need to be clarified in clinical trial s. Int. J. Cancer (Pred. Oncol.) 84:426-431, 1999. (C) 1999 Wiley-Liss, Inc .