Urine Telomerase Research Articles

Relevance of Urine Telomerase in the Diagnosis of Bladder Cancer

Relevance of Urine Telomerase in the Diagnosis of Bladder Cancer

Accurate urine telomerase test for detecting bladder cancer

Accurate urine telomerase test for detecting bladder cancer

Relevance of Urine Telomerase in the Diagnosis of Bladder Cancer

The identification of new molecular markers is one of the most challenging goals for the early detection of bladder cancer because available noninvasive methods have neither sufficient sensitivity nor specificity to be acceptable for routine use. To develop a relatively simple, inexpensive, and accurate test that measures telomerase activity in voided urine to apply to large-scale screening programs for bladder cancer detection. Case-control study conducted in 218 men (84 healthy individuals and 134 patients at first diagnosis of histologically confirmed bladder cancer), frequency matched by age and recruited between March 2003 and November 2004 in Italy. Urine telomerase activity was determined using a highly sensitive telomeric repeat amplification protocol (TRAP) assay. Urine samples were processed for cytological diagnosis and TRAP assay. The diagnosis of bladder cancer was based on bioptic and cystoscopic examinations. The performance of the TRAP assay to detect urine telomerase activity was compared with urine cytology as an aid to early cancer detection. Quantification of urine telomerase activity was conducted in a blinded manner. Sensitivity and specificity of TRAP to detect bladder cancer. Using a 50 arbitrary enzymatic unit cutoff value, we validated the results obtained in the pilot study. In the overall series, sensitivity was 90% (95% confidence interval [CI], 83%-94%) and specificity was 88% (95% CI, 79%-93%). Specificity increased to 94% (95% CI, 85%-98%) for individuals aged 75 years or younger. The same predictive capacity of telomerase activity levels was observed for patients with low-grade tumors or with negative cytology results. The present validation study demonstrated the ability of urine telomerase activity levels to accurately detect the presence of bladder tumors in men. This test represents a potentially useful noninvasive diagnostic innovation for bladder cancer detection in high-risk groups such as habitual smokers or in symptomatic patients.

Urine Telomerase: An Important Marker in the Diagnosis of Bladder Cancer

Telomerase activity is present in most human malignant tumors, whereas it is generally not detectable, with some exceptions, in normal cells. Therefore, it represents a potential tool for tumor detection. In the present study, telomerase activity was determined in urine from 79 healthy individuals and 121 previously untreated bladder cancer patients using a highly sensitive telomeric repeat amplification protocol (TRAP) assay and the results were expressed as arbitrary enzymatic units (AEU). This approach enabled us to identify cutoff values characterized by high sensitivity (from 75% to 93%) and specificity (from 72% to 92%). Moreover, analysis as a function of gender showed a higher accuracy of TRAP assay in males (93% sensitivity and 90% specificity at the cutoff of 50 AEU) than in females. This sensitivity was confirmed in patients with nonassessable or negative cytology. In women, morphological and immunocytochemical determinations using a human telomerase reverse transcriptase monoclonal antibody (anti-hTERT) recently developed in our laboratory showed a large fraction of immunoreactive inflammatory or nonbladder cells, which may justify the false-positive TRAP results. In conclusion, this assay represents an important noninvasive diagnostic tool to detect bladder cancer also in patients with negative or nonassessable urine cytology and with low-grade and early-stage lesions.

Comparison of telomerase activity and matrix metalloproteinase-9 in voided urine and bladder wash samples as a useful diagnostic tool for bladder cancer.

This study was undertaken to evaluate the diagnostic efficacy of telomerase in urine, and bladder wash and also the matrix metalloproteinase-9 (MMP-9) in urine, compared with voided urine cytology (VUC) and bladder wash cytology (BWC) for the detection of bladder cancer cells. A total of 110 subjects provided a single preoperative voided morning urine sample for telomerase, matrix metalloproteinase-9 (MMP-9) and cytology. Bladder wash samples were obtained for telomerase and cytology. Cystoscopy was done for all patients as the reference standard for the identification of bladder cancer. Biopsy of any suspicious lesion was performed for histopathological examination. Of 110 cases 73 were histologically diagnosed as bladder cancer, whereas the remaining 16 had benign urological disorders. A group of 21 healthy volunteers were also enrolled in this study. The optimal threshold values for telomerase activity in urine, bladder wash and MMP-9 were calculated by receiver-operator characteristics (ROC) curves as 0.05, 0.088 and 0.51 (ng/ml), respectively. The levels and the positivity rates of the 2 parameters were significantly higher in the malignant group compared to either the benign group or normal controls. Of the entire group, telomerase activity in urine, bladder wash, and MMP-9 were positive in 92%, 87% and 61%, respectively in bladder cancer patients with positive cytology. Moreover, these positive rates for them were significantly higher in bilharzial bladder cancer cases (88%, 89%, 69%, respectively) compared to non-bilharzial cases (50%, 62.5%, 50%). The overall sensitivity and specificity were 83% and 88.6%, 86.3% and 78.3% for telomerase activity in urine, and in bladder wash, respectively; 66.6% and 80% for MMP-9 and 58.5% and 100% for voided urine cytology and 64.4% and 100% for bladder wash cytology. Combined sensitivity of VUC with the 2 biomarkers together was higher than either combined sensitivity of VUC with one of the biomarkers or than that of the biomarker alone. Our data indicate that urinary telomerase and MMP-9 had superior sensitivities over VUC. The combined use of markers increased the sensitivity of cytology from 58.46% to 95%. The higher sensitivities of markers in bilharzial bladder cancer than non-bilharzial type highlight their clinical utility in screening patients with urinary bilharziasis.

Comparison of Human Telomerase RNA and Telomerase Activity in Urine for Diagnosis of Bladder Cancer

New, noninvasive methods for the early detection of urothelial carcinomas of the urinary bladder are needed for the diagnosis, follow-up, and screening of patients with bladder cancer. Detection of the enzyme telomerase in urine could offer these new diagnostic possibilities. The standard technique for detecting telomerase activity is the telomeric repeat amplification protocol (TRAP assay). Because of the instability of the ribonucleoprotein telomerase in an aggressive medium, such as urine, investigations conducted to date have yielded nonuniform or even contradictory findings. This study compares the detection of human telomerase RNA (hTR) by reverse transcriptase-PCR (RT-PCR) with detection of telomerase activity by the TRAP assay in the diagnosis of urothelial carcinoma of the urinary bladder. Sedimented cells obtained from urine of 30 patients with urothelial carcinoma, 15 patients with benign urological disorders, 3 patients as part of follow-up for malignant disease, and 20 healthy subjects were examined for the presence of hTR and for telomerase activity (TRAP). In patients with bladder cancer, telomerase activity was detected by the TRAP assay in only 2 of 30 specimens (7%). However, increased levels of hTR were detected by RT-PCR in 25 of the same 30 cases (83%). For patients with benign urological disorders, such as urolithiasis or urinary tract infections, hTR was detected in samples obtained from 4 of 15 patients (27%). Low hTR expression levels were found in 15% of the healthy controls. The detection of hTR by RT-PCR represents a promising new method for detecting malignant cells in urine.

Comparison of Human Telomerase RNA and Telomerase Activity in Urine for Diagnosis of Bladder Cancer

New, noninvasive methods for the early detection of urothelial carcinomas of the urinary bladder are needed for the diagnosis, follow-up, and screening of patients with bladder cancer. Detection of the enzyme telomerase in urine could offer these new diagnostic possibilities. The standard technique for detecting telomerase activity is the telomeric repeat amplification protocol (TRAP assay). Because of the instability of the ribonucleoprotein telomerase in an aggressive medium, such as urine, investigations conducted to date have yielded nonuniform or even contradictory findings. This study compares the detection of human telomerase RNA (hTR) by reverse transcriptase-PCR (RT-PCR) with detection of telomerase activity by the TRAP assay in the diagnosis of urothelial carcinoma of the urinary bladder. Sedimented cells obtained from urine of 30 patients with urothelial carcinoma, 15 patients with benign urological disorders, 3 patients as part of follow-up for malignant disease, and 20 healthy subjects were examined for the presence of hTR and for telomerase activity (TRAP). In patients with bladder cancer, telomerase activity was detected by the TRAP assay in only 2 of 30 specimens (7%). However, increased levels of hTR were detected by RT-PCR in 25 of the same 30 cases (83%). For patients with benign urological disorders, such as urolithiasis or urinary tract infections, hTR was detected in samples obtained from 4 of 15 patients (27%). Low hTR expression levels were found in 15% of the healthy controls. The detection of hTR by RT-PCR represents a promising new method for detecting malignant cells in urine.