A combination of semiquantitative telomerase assay and in-cell telomerase activity measurement using exfoliated urothelial cells for the detection of urothelial neoplasia.

BACKGROUND

Telomerase is a ribonucleoprotein that synthesizes telomeres. It is detected in more than 85% of samples obtained from cancer tissues, including urologic neoplasia. The authors determined telomerase activity semiquantatively and in-cell telomerase activity in exfoliated urothelial cells obtained from urologic neoplasia specimens. The goal of this study was to provide additional information regarding a noninvasive approach to the detection of urologic neoplasia.

METHODS

The authors used voided urine from 23 patients with urologic neoplasia, 2 patients with nonmalignant urologic disorders, and 10 normal individuals. Semiquantative determination of telomerase activity was performed using a fluorescence-based telomeric repeat amplification protocol (TRAP), and telomerase activity at the cellular level was determined by an in situ TRAP assay.

RESULTS

The fluorescence-based TRAP assay detected urinary telomerase activity in samples from 10 of 13 patients with urologic neoplasia before treatment, whereas urinary cells obtained from 3 of 10 patients (including 1 patient with relapse) during or after treatment had detectable telomerase activity. In contrast, the in situ TRAP assay detected telomerase positive cells in samples from 11 of 13 patients before treatment and 6 of 10 patients during or after treatment. Of note was a dissociation of the results of the fluorescence-based TRAP assay and those of the in situ TRAP assay for some patients. Some patients for whom telomerase activity was not detected with the fluorescence-based TRAP assay had a low frequency of telomerase positive cells in their urine.

CONCLUSIONS

A combination of semiquantative analysis and an in situ TRAP assay to detect telomerase positive cells might be a useful tool in the identification and monitoring of patients with urothelial neoplasia.