Seven samples from seven patients with
juxtacortical osteosarcomas, and 27 samples from 19 patients with conventional high-grade
osteosarcomas were investigated for a possible correlation between
telomerase activity and clinicopathological features such as age, sex, and response to
chemotherapy. Of seven
juxtacortical osteosarcomas,
telomerase activity was weakly positive in three parosteal
osteosarcomas, and highly positive in one parosteal
osteosarcoma. In contrast, of 27 conventional high-grade
osteosarcomas,
telomerase activity was weakly positive in eight
tumors and highly positive in three. Of all samples, 44.1% of the
osteosarcomas showed
telomerase activity (57.1% of juxtacortical and 40.7% of conventional
osteosarcomas). The majority of poor responders to
chemotherapy showed no
telomerase activity (nine of 11), whereas five of seven good responders showed strong or weak
telomerase activity. There was a significant correlation between
telomerase activity and the response to
chemotherapy (P<0.05).
Telomerase activity was not correlated with MIB-1 proliferation index, age at the time of surgery, or sex. These findings suggest that
telomerase activation occurs early in the
oncogenesis of osteoblastic
tumors without having an effect on the progression of these
tumors. In malignant osteoblastic
tumors, the
biological significance of
telomerase activation is different from that described for most epithelial
cancers.