Diagnosis of bladder cancer by detecting telomerase in urine

Purpose: There is a need for new non-invasive methods for the diagnosis of carcinoma of the urinary bladder. Detection of the enzyme telomerase in uri ne could offer these new diagnostic possibilities. The standard technique f or detecting telomerase activity is the TRAP assay (telomeric repeat amplif ication protocol). Because of the instability of the ribonucleoprotein telo merase in an aggressive medium, such as urine, investigations conducted to date have yielded non-uniform or even contradictory findings. Thus, the obj ective of the present study was to establish a more reliable detection meth od for telomerase in urine. Therefore we examined the detection of the rece ntly determined RNA portion of human telomerase (hTR) by RT-PCR and compare d it to telomerase activity. Materials and Methods: Urine samples were obta ined prior to surgery from 35 patients with confirmed bladder cancer, 24 pa tients with other urologic disorders (urolithiasis, urinary tract infection s) and from 38 healthy volunteers. Each sample was examined for the presenc e of human telomerase RNA (hTR) and telomerase activity. Identification of: hTR was performed using a RT-PCR method, while telomerase activity was det ected using the PCR based TRAP assay. For both methods new non radioactive detection methods were used. Results: Increased levels of hTR were found in 29 of 35 urine samples (sensitivity 83%, specifity 82%) obtained from pati ents with bladder cancer. Telomerase activity was detected in only 2/35 (6% ) of these same cases. In healthy volunteers RT-PCR detected hTR at low lev els in 5 of 38 (13%) samples, but telomerase activity was not observed. For patients with benign urologic disorders such as urolithiasis or urinary tr act infections hTR was detected in samples obtained from 6 out of 24 patien ts (25%). Conclusions: The detection of hTR by RT-PCR represents a promisin g new method for detecting malignant cells in urine which is practicable fo r routine clinical use.