Urine micro-RNA signature as a potential non-invasive diagnostic biomarker in bladder cancer

Background: Bladder cancer (BC) is one of the most prevalent malignancies worldwide, 70% of patients initially diagnosed with superficial BC. In addition, 20% of BC patients with recurrence experience disease progression. Thus, identification of novel biomarkers for diagnosis, prognosis and therapeutic targets of BC will help to advance clinical diagnosis and treatment of this disease. MicroRNAs (miRNAs) are single stranded, non coding RNAs that are hypothesized to regulate gene expression at the post transcriptional level. This study aimed to assess the urine and tissue expression levels of miR-200, miR-145 and miR-21 in BC patients o evaluate their potential as noninvasive biomarkers. Subjects and methods: Urine and their corresponding tissue samples were collected from 111 BC patients and from 25 healthy controls. A quantitative real-time polymerase chain reaction method based on a TaqMan probe was used to evaluate the expression levels of miR‑200, miR‑145 and miR-21, the correlations between these miRNA expression levels in urine and tissues and certain clinicopathological parameters were investigated. Results: The expression of the 3 studied miRNAs was significantly higher in urine of low and high tumor grade BC patients compared to the controls and the expression were increased in BC tissues compared with those in normal bladder tissues, the results proved that the 3 miRNAs function as oncogenes. A marked positive correlation was observed between the mRNA expression of miR-200 and miR 21, with a coefficient of 0.511 and P value of 0.02. Conclusion: The results of the present study indicated that miR-200, miR-145 and miR-21 may function as oncogenes and have a potential to serve as an early noninvasive diagnostic biomarkers and therapeutic targets for treatment of BC.