miR-143, miR-222, and miR-452 are useful as tumor stratification and noninvasive diagnostic biomarkers for bladder cancer.

Altered microRNA (miRNA) expression may occur early in bladder cancer and may play a role in carcinogenesis and tumor behavior. We evaluated whether alterations in miRNA expression could improve disease stratification and outcome prognosis in bladder tumors and noninvasive diagnosis in urinary samples. miR-143, miR-222, and miR-452 expression levels were analyzed by quantitative RT-PCR (RT-qPCR) in paired urinary and matching tumors and in two independent prospective series of tumors and urinary specimens. Differential expression of miR-143, miR-222, and miR-452 in urine were verified by in situ hybridization in matching tumors. Tumor miRNA expression by RT-qPCR correlated with tumor grade, size, and presence of carcinoma in situ for miR-222, recurrence (miR-222 and miR-143), progression (miR-222 and miR-143), disease-specific survival (miR-222), and overall survival (miR-222). Protein expression patterns of potential miRNA targets, including vascular endothelial growth factor, BCL2, v-erb-b2 erythroblastic leukemia viral oncogene (ERBB) homolog 3, and ERBB4, were evaluated by IHC in tissue arrays containing tumors for which miRNAs were assessed by RT-qPCR. Target expression correlated with expression of their predicted regulatory miRNAs, recurrence (ERBB3), progression (ERBB4), disease-specific survival (ERBB3 and ERBB4), and overall survival (ERBB3 and ERBB4). Furthermore, RT-qPCR of miR-452 (area under the curve, 0.848) and miR-222 (area under the curve, 0.718) in urine provided high accuracies for bladder cancer diagnosis. Thus, bladder tumors were characterized by changes in miRNA expression that could aid in tumor stratification and clinical outcome prognosis, and miRNAs were detected in urinary specimens for noninvasive diagnosis.