Telomerase activity and telomere length in primary and metastatic tumors from pediatric @entity3478 XXXX .

@entity1 @entity2828 @entity242 @entity3478 @entity5 @entity421
The presence of telomerase activity has been analyzed in almost all @entity5 types and @entity5 -derived cell lines. However, there are very few studies that focus on the presence of telomerase activity in @entity3478 , and most of them report analysis on very few samples or bone-derived cell lines. The objective of this study was to analyze the telomere length and telomerase activity in @entity5 and metastatic lesions from @entity421 and @entity2828 @entity1 . The presence of telomerase activity was analyzed by the telomeric repeat amplification protocol assay, and the telomere length was measured by Southern blot. Results were related to survival and clinical outcome. Telomerase activity was detected in 85% of the @entity3478 metastases (100% Ewing's @entity242 and 75% @entity421 ) but only in 12% of the @entity5 (11.1% @entity421 and 12.5% Ewing's @entity242 ). @entity3478 tissues with telomerase activity had mean telomere lengths 3 kb shorter than those with no detectable telomerase activity (p = 0.041). The presence of telomerase activity was associated with survival (p = 0.009), and longer event-free survival periods were found in @entity1 who lacked telomerase activity compared with those who had detectable telomerase activity levels in their @entity5 tissues (p = 0.037). The presence of longer telomeres in primary pediatric @entity3478 than in metastases could be indicative of alternative mechanisms of lengthening of telomeres for their telomere maintenance rather than telomerase activity. Nevertheless, the activation of telomerase seems to be a crucial step in the malignant progression and acquisition of invasive capability of @entity3478 .
