Cell-free microRNAs in urine as diagnostic and prognostic biomarkers of bladder cancer
Yun SJ, Jeong P, Kim WT, Kim TH, Lee YS, Song PH, Choi YH, Kim IY, Moon SK, Kim WJ. Int J Oncol. 2012 Nov;41(5):1871-8. doi: 10.3892/ijo.2012.1622. Epub 2012 Sep 6.


Department of Urology, Chungbuk National University College of Medicine, Cheongju, Republic of Korea.


miRNAs are small, non-coding RNAs that play important roles in various biological processes. The aims of our study were to investigate whether cell-free miRNAs can be measured in urine samples and might be an accurate biomarker of bladder cancer. Datasets of GSE20418 and GSE19717 were used for analysis, and two miRNAs, miR-145 and miR-200a, were selected for study. A total of 207 patients with primary transitional cell carcinoma of the urinary bladder and 144 healthy normal controls were enrolled. Using quantitative PCR, the levels of miR-145 and miR-200a in urine were measured and compared with the clinicopathological features of bladder cancer. According to our experiments, cell-free miRNAs were present in urine and were stable. Assessment of miR-145 levels was able to distinguish bladder cancer patients from non-cancer controls (77.8% sensitivity and 61.1% specificity for NMIBC, AUC 0.729; 84.1 and 61.1% for MIBC, respectively, AUC 0.790) and showed good correlation with grade (p=0.048). In addition, miR-200a was shown to be an independent predictor of NMIBC recurrence by multivariate analysis (OR 0.449, 95% CI 0.239‑0.842, p=0.013). A higher risk of recurrence was observed among patients with a lower miR-200a level compared to patients with higher miR-200a levels (log-rank test, p=0.040). Urinary cell-free miRNAs show promise as noninvasive biomarkers for diagnosis and recurrence of bladder cancer.