Telomerase activity in soft-tissue and bone sarcomas

The telomerase enzyme is a reverse transcriptase capable of replacing the t elomeric DNA sequences that are lost at each cell division, Telomerase acti vation permits extended cell proliferation beyond normal senescence checkpo ints, and accordingly, telomerase activity has been detected in a wide rang e of malignant cells and tissues but is absent in terminally differentiated somatic cells. To date, the majority of cancer-related telomerase analyses have been performed on carcinomas that originate from epithelial cells, an d few reports have included tumors originating from nonepithelial cells. In this study, we used the PCR-based telomeric repeat amplification protocol (TRAP) to assay telomerase activity in nuclear protein extracts obtained fr om a range of malignant and benign connective tissue lesions, In total, 62 histologically diagnosed specimens were analyzed including 37 sarcomas, 7 b enign mesenchymal tumors, 12 normal tissue samples, and 6 carcinoma metasta ses obtained from bone. Thirty (81%) of the 37 primary sarcoma samples cont ained telomerase activity, and four of the six carcinoma metastases were al so positive. Conversely, telomerase activity was detectable in only one of seven benign lesions and in none of the 12 normal connective tissue control s, Tumors of connective tissue origin can sometimes be difficult to categor ize and to evaluate microscopically with regard to clinical management. As is the case in carcinomas, the presence of telomerase activity appears to b e indicative of malignancy in mesenchymal tumor biopsy material and therefo re may be useful as an adjunct to the pathologist in the assessment of bord erline cases.