The Diagnostic and Prognostic Significance of MicroRNA-21 in Non-muscle Invasive Bladder Tumors

Bladder cancer (BC) is one of the commonly diagnosed urological cancers that causes human death, ranked as the seventh most common cancer worldwide. To date, no reliable diagnostic tool has been defined to recognize non-muscle invasive bladder tumors other than cystoscopy. For this reason, scientists have focused on finding new non-invasive biomarkers that can be used to diagnose BC with higher specificity and sensitivity. The purpose of this study was to evaluate the diagnostic role and prognostic significance of microRNA-21 (miR-21) in non-muscle invasive bladder tumors. In this review, the overall diagnostic performance of miR-21 was discussed on non-invasive BC based on a literature search of PubMed and Cochrane Library. Although findings are insufficient, promising results have been reported regarding circulating miR-21 as a biomarker for BC prospective studies with larger numbers of participants are needed. Keywords: Non-muscle invasive bladder tumor, microRNA-21, diagnostic marker