The simultaneous use of telomerase, cytokeratin 20 and CD4 for bladder cancer detection in urine.

Objective: Because of the low sensitivity of urinary cytological diagnosis of urinary bladder carcinoma, new molecular diagnostic methods have been proposed. We decided to verify the expression of telomerase mRNA coding for the catalytic component (hTRT), cytokeratin 20 (CK20) and CD4 antigen mRNAs in urine as possible diagnostic tool.

Methods: Evaluation of hTRT, CK20, CD4 mRNAs was performed in 50 ml of naturally voided urine of 205 patients of which 153 with bladder cancer (Tis, n = 11; TaGx, n = 4; TaG1, n = 25; TaG2, n = 26; TaG3, n = 8; T1G1, n = 16; T1G2, n = 17; T1G3, n = 20; T2G2, n = 6; T2G3, n = 13; T3G3, n = 7) and 52 controls. A quantitative expression of hTRT at mRNA level versus TRAP (telomeric repeat amplification protocol) assay was performed in 20 patients and 14 controls. The expression of RT-PCR for hTRT, CK20, CD4 versus urinary cytology was analysed in 44 patients with bladder cancer. Evaluating the three molecular markers together, the result was considered correct when at least two of the markers were positive, suspected when only one marker was positive and negative for diagnosis of tumour when all markers were negative. The performance of the diagnostic model resulted from the logistic analysis evaluated with receiver operating characteristics (ROC) curve analysis.

Results: The sensitivity detected for each tumour marker was as follows: for hTRT 90.8%, for CK20 84.3% and for CD4 was 64.7%, while the specificity was 94.2% for CD4 and 78.8% for both hTRT and CK20. When a simultaneous evaluation of the three tumour markers was considered, 88.2% of the diagnoses were correct, 11.8% were suspected for tumour and none were mistaken. When compared with cytology, the simultaneous use of the three markers allowed reaching a correct diagnosis in 88% of the cases in comparison to 25% by urinary cytology. The sensitivity in the detection of bladder cancer was higher for hTRT at mRNA level in comparison with the enzymatic activity detection with TRAP (90% vs. 35%) while the specificity for both markers resulted very high (100%).

Conclusions: These data show that in the future the diagnostic improvement of urine based molecular markers for the detection of bladder cancer in the urine could improve the sensitivity of urinary cytology reducing the need of a cystoscopy.