Quantitative measurement of telomerase reverse transcriptase mRNA and chromosomal analysis of urine by M-FISH in the diagnosis and follow-up of bladder cancer

Abstract

This study was performed to evaluate the clinical utility of the measurement of the expression of telomerase enzyme (the catalytic subunit of the complex hTERT) and of the chromosomal analysis of urine by multicolor fluorescence in situ hybridization (M-FISH) assay for the detection of bladder cancer and its recurrence. These results were compared with those afforded by urine cytology, hematuria screening and the bladder tumor antigen (BTA) and fibrin degradation products (FDP) tests. Urine samples were obtained from three groups: 30 patients with bladder cancer, 15 patients with non-malignant bladder disorders and 8 healthy individuals. hTERT mRNA was measured by reverse transcription real-time PCR. M-FISH was performed using a mixture of fluorescent labeled probes for the centromeric regions of chromosomes 3, 7, 17, and the locus specific identifier p16 probe for the 9p21 locus. We demonstrated that the overall sensitivity of hemoglobin dipstick and the BTA and FDP tests was insignificantly greater than that of urine cytology, but with a lower specificity. The hTERT mRNA expression marker offered significantly greater sensitivity for detecting all bladder cancers, especially superficial and low grade tumors, than did urine cytology, and with a higher specificity. M-FISH was significantly more sensitive than urine cytology in detecting bladder tumors, but had lower specificity (insignificant results). The superior sensitivity of M-FISH was maintained when comparing the two assays in terms of low-stage and low grade tumor detection. M-FISH was the most sensitive and specific test in detecting tumor recurrence, followed by the BTA test. hTERT, hematuria screening and FDP showed relatively low sensitivity and low specificity during follow-up. Our findings suggest that the assessment of hTERT expression and chromosomal abnormalities in urine represent reliable tools - equally specific yet far more sensitive than conventional cytology - for the early detection of bladder cancer. The high sensitivity of FISH in detecting recurrence makes it useful for reducing the number of cyctoscopies usually performed in the accurate follow-up of these cases.