Chondrosarcoma is not characterized by detectable telomerase activity

Reactivation of telomerase, an enzyme which elongates human telomeres, is a ssociated with cell immortilization, In approximately 90% of malignant tumo urs telomerase activity can be demonstrated, whereas in benign tumours it i s mostly absent. Chondrosarcomas are relatively rare malignant cartilaginou s neoplasms, A small number of chondrosarcomas located centrally in bone ar ise secondarily to an enchondroma, while the majority of chondrosarcomas de l eloping from the surface arise within the cartilage cap of an osteochondr oma, The histological distinction between a benign lesion and low-grade cho ndrosarcoma is generally considered difficult. To investigate whether the p rogression towards chondrosarcoma is characterized by reactivation of telom erase activity, this study determined telomerase activity in ten enchondrom as, five osteochondromas, and 37 chondrosarcomas using the TRAP assay, In a ll tumour samples except one, telomerase activity: was absent. By adding tu mour lysates to the positive control, an increasing inhibition of telomeras e activity was found with an increasing chondroid matrix, suggesting that i t may contain inhibitory factors. Inhibition due to endogenous RNAse or Taq -polymerasc inhibitors was excluded, The lack of detectable telomerase acti vity in the high-grade component of a dedifferentiated chondrosarcoma witho ut matrix favours the possibility that telomerase is truly. absent, Either its true absence or inhibitory effects disabling telomerase detection exclu de the telomerase TRAP assay as a diagnostic tool in the differential diagn osis of benign and low-grade malignant cartilaginous tumours, Copyright (C) 2000 John Wiley & Sons, Ltd.