Telomeres and telomerase in sarcomas.

Telomeres of human tumor cells have two types of telomere maintenance mechanisms by telomerase activation and alternative lengthening of telomeres (ALT). Although over 80% of all carcinomas rely on telomerase activity to maintain stable telomere length, many types of sarcoma elongate telomeres consistent with ALT in the absence of telomerase activity. Recently, the presence of telomerase activity and ALT in several sarcomas was examined extensively, and recent studies indicate a positive correlation between the telomere maintenance mechanism and tumor aggressiveness in several sarcoma types. We reviewed both the activation of telomere maintenance in a variety of common bone and soft tissue sarcoma subtypes, and the consequences of telomere maintenance mechanisms with respect to the clinical characteristics.