Andrew AS, et al. - In three independent cohorts of patients diagnosed with primary non-muscle invasive bladder cancer, researchers looked for reproducible prognostic microRNAs (miRNAs) in resected non-muscle invasive bladder tumor tissue that were predictive of the recurrent tumor phenotype. They used a discovery cohort comprising 38 patients with the clinically challenging, non-muscle invasive primary low stage, Ta high-grade and T1 tumors, and two independent longitudinal cohorts that included both low-grade and high-grade Ta and T1 tumors for validation. The tumor tissue RNA was isolated and a panel of ~800 miRNAs was evaluated. Findings suggested the possible utility of miR-26b-5p levels to be prognostic for non-muscle invasive bladder cancer recurrence. Moreover, it could be feasible to evaluate these levels in baseline tumor tissue from a wide variety of clinical settings. A consistent link between miR-26b-5p and recurrence and progression was seen in the validation cohorts.