Urine miR-21-5p as a potential biomarker for predicting effectiveness of tadalafil in benign prostatic hyperplasia

AIM: To investigate whether urine levels of miRNAs that regulate the function of endothelial cells are associated with effectiveness in benign prostatic hyperplasia (BPH) patients treated with a phosphodiesterase type 5 inhibitor, tadalafil. PATIENTS & METHODS: We measured urine levels of three miRNAs (miR-21-5p, miR-126-5p & miR-155-5p) in 55 BPH patients before and after tadalafil administration to understand its effectiveness. RESULTS: Baseline urine miR-21-5p level was an independent predictor of response to tadalafil in multivariate regression analysis (odds ratio: 0.28; 95% CI: 0.10–0.77; p = 0.014). Receiver operator curve analysis revealed that baseline urine miR-21-5p could serve as a predictor of response (area under curve: 0.85; 95% CI: 0.75–0.95; p < 0.001). CONCLUSION: Urine miR-21-5p could serve as a biomarker in predicting response of tadalafil for BPH.