Detection of Bladder Cancer by Measuring CD44v6 Expression in Urine With Real-time Quantitative Reverse Transcription Polymerase Chain Reaction

Abstract

To examine urinary CD44v6 total ribonucleic acid (RNA) expression in patients with bladder cancer using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and evaluate its potential as a novel marker of bladder cancer. We used the bladder cancer cell line T24 and determined CD44v6 expression in cancer cells using in situ hybridization and immunohistochemistry. Subsequently, we obtained urine samples from 21 patients with bladder cancer and 25 patients without bladder cancer (controls). We extracted total RNA from the urine samples, measured CD44v6 total RNA expression in both groups using qRT-PCR, and compared the expression between groups. We also compared the sensitivity, specificity, and concordance rate between CD44v6 total RNA expression analysis by qRT-PCR and cytologic analysis, UroVysion fluorescent in situ hybridization, bladder tumor antigen identification, and nuclear matrix protein 22 measurements. We observed increased CD44v6 expression in bladder cancer cells using in situ hybridization and immunohistochemistry. CD44v6 total RNA expression was significantly higher in the urine samples of patients with bladder cancer than in those of controls. We calculated the cutoff value from the receiver operating characteristic curve and obtained sensitivity and specificity values of 85.7% and 72.0%, respectively, for qRT-PCR analysis. Our results suggest that CD44v6 total RNA levels in urine can serve as a potential noninvasive biomarker of bladder cancer.