Exosomes contain a variety of molecules that exhibit biological activity, such as proteins, lipids, and nucleic acids, and reflect the states and types of their cells of origin 2– 4. Therefore, there is a significant clinical need to find biomarkers for new classification systems to improve decision making in intermediate-risk prostate cancer.Įxosomes are small extracellular vesicles secreted by cells and are present in various body fluids, including blood, urine, saliva, tears, semen, breast milk, and ascites. More precise stratification of intermediate-risk prostate cancer is important in making optimal decisions for patients among a variety of treatment options, including radical prostatectomy (RP), radiotherapy (RT), focal therapy, and active surveillance. Of the three groups, intermediate-risk prostate cancer is the most heterogeneous disease and reveals various oncological outcomes. Most cases of prostate cancer are clinically localized, and they are divided into low, intermediate, or high-risk groups by D'Amico's classification. Prostate cancer is the second most commonly diagnosed cancer in men in the world, and it is the fifth leading cause of cancer deaths 1. Further research is needed on the biological functions and mechanisms of this miRNA. In conclusion, miR-532-5p in urine exosomes might be a potential biomarker for predicting BCR, which is a poor prognosis in patients with intermediate-risk prostate cancer. The univariate and multivariate Cox regression analyses showed that miR-532-5p was an important predictive factor for BCR of intermediate-risk prostate cancer. A validation analysis revealed that three miRNAs (miR-26a-5p, miR-532-5p, and miR-99b-3p) were upregulated in exosomes from BCR patients. For external validation, we validated these results using quantitative reverse transcription PCR in an independent cohort of 28 non-BCR patients and 26 BCR patients. A total of 21 urinary exosomal miRNAs were found to be differentially expressed (> twofold) in BCR patients compared to non-BCR patients. We profiled the expression levels of miRNAs via next generation sequencing in urinary exosomes from 21 non-BCR patients and 6 BCR patients of intermediate-risk prostate cancer. In this study, we aimed to identify urinary exosomal miRNAs as prognostic markers associated with BCR in intermediate-risk prostate cancer. MiRNAs have been linked to factors associated with aggressive prostate cancer such as biochemical recurrence (BCR) and metastasis. MicroRNAs (miRNAs) of urine exosomes have emerged as biomarkers for urological cancers, owing to their high stability.