Downregulation of miR-133b predict progression and poor prognosis in patients with urothelial carcinoma of bladder

We found microRNA-133b (miR-133b) was downregulated in urothelial carcinoma of the bladder (UCB) tissues, and it could inhibit the proliferation and induce apoptosis in UCB cells. Consequently, we intend to explore the clinical significance of miR-133b in UCB patients. Expression of miR-133b in 146 UCB specimens and matched adjacent non-neoplastic bladder tissues were measured by quantitative real-time polymerase chain reaction. The overall survival (OS) curve and progression-free survival (PFS) curve were plotted using the Kaplan-Meier method. Prognostic factors for OS and PFS were identified by univariate and multivariate analyses using the Cox proportional hazards regression model. The expression of miR-133b was significantly downregulated in UCB tissues compared with those in adjacent non-neoplastic bladder tissues (P<0.001). Among UCB patients, low expression of miR-133b significantly correlated with aggressive clinicopathological features. Multivariate analysis indicated that the expression of miR-133b was the independent prognostic factors for predicting PFS (RR: 2.97; 95% CI: 1.78-6.44; P=0.009) and OS (RR: 4.23; 95% CI: 1.51-11.8; P=0.011) in patients with UCB. Our study demonstrated that downregulation of miR-133b associated with aggressive clinicopathological features and predicted unfavorable prognosis in patients with UCB, might serve as feasible biomarker for clinical outcome of UCB patients after surgery and potential therapeutic target in the future.