Telomeres and their maintenance by
telomerase have been implicated to play an important role in
carcinogenesis. As almost all malignant
tumors express
telomerase (in contrast to normal somatic cells), assessment of its activity has been proposed as a diagnostic and prognostic tool. To test the prognostic value of
telomerase in pediatric
soft tissue sarcoma (STS), we analyzed telomere length (by telomere restriction fragment analysis),
telomerase activity (by modified
telomerase repeat amplification protocol assay), and expression of human
telomerase reverse transcriptase (hTERT)
mRNA (by TaqMan technique) in cell lines of different types of STS from 12 children and adolescents. Telomere length (3.7-9.0 kb) showed a very heterogeneous pattern, independent of subtype of STS or the age of the patients, and it was not associated with expression of hTERT
mRNA. In contrast, there was a trend of an association between hTERT and
telomerase activity. The three tested cell lines of
embryonal rhabdomyosarcomas demonstrated no or low (n = 2)
telomerase activity, which was confirmed in two cases by a very low expression of hTERT
mRNA. Thus, we suggest that the significant difference (p < 0.01) in the less aggressive clinical behavior of
embryonal rhabdomyosarcomas in comparison to other subtypes may be due to differences in
telomerase expression. Taken together, our cell line experiments imply that
telomerase activity might be a
biologic marker for stratification between STS with different clinical prognosis.