Cross-sectional and longitudinal analyses of urinary extracellular vesicle mRNA markers in urothelial bladder cancer patients

We designed this multi-center prospective study with the following objectives: (1) the cross-sectional validation of extracellular vesicles (EV) mRNA markers to detect urothelial bladder cancer (UBC) before transurethral resection of bladder cancer (TURBT), and (2) the longitudinal validation of EV mRNA markers to monitor non-muscle invasive bladder cancer (NMIBC) recurrence after TURBT. EV mRNA markers evaluated in this study were KRT17, GPRC5A, and SLC2A1 in addition to two additional markers from literatures, MDK and CXCR2, and measured by quantitative RT-PCR with normalization by a reference gene (ALDOB). Diagnostic performances of EV mRNA markers were compared to conventional markers. Regarding the first objective, we confirmed that EV mRNA biomarkers in urine were higher in UBC patients, particularly those with higher stage/grade tumors, than in those without UBC (n = 278 in total) and the diagnostic performance of EV mRNA MDK and KRT17 outperformed conventional biomarkers with AUC 0.760 and 0.730, respectively. Concerning the second objective, we prospectively analyzed the time courses of EV mRNA markers while NMIBC patients (n = 189) (median follow-up 19 months). The expression of EV mRNA KRT17 was significantly high in patients with recurrence, while it gradually decreased over time in those without recurrence (p < 0.01).