Evaluation of Urinary DNA Methylation as a Marker for Recurrent Bladder Cancer: A 2-Center Prospective Study

Objective To clarify the clinical utility of urinary DNA methylation for detection of intravesical recurrence of non–muscle invasive BCa (NMIBC), we performed a 2-center prospective study. Patients and Methods A series of 207 self-voided urine samples were prospectively collected from 132 patients with NMIBC who had undergone transurethral resection of BCa. Methylation of miRNA genes ( miR-9-3 , miR-124-2 , miR-124-3 , and miR-137 ) was analyzed using bisulfite pyrosequencing. The primary end point was detection of intravesical recurrence; the secondary end point was prediction of late recurrence. The number of methylated genes (M-score) or quantitative level of methylation were compared with outcomes. Results Twenty-six urine specimens were collected on the same day intravesical recurrence was detected, and 14 were collected from patients whose recurrences were found during the subsequent follow-up period (0-632 days, mean, 342.2 days). For detection of current recurrence, M-scores achieved 61.5% sensitivity and 74.0% specificity, and the area under the ROC curve was 0.71. Regarding prediction of late recurrence, patients with a high M-score (≥3) showed worse recurrence-free survival ( P  P  = .028) and late recurrence ( P  = .026). Elevated levels of urinary DNA methylation were also strongly associated with recurrence and radical cystectomy. Conclusion Our data suggest that urinary methylation of miRNA genes may be a useful marker for detecting and predicting BCa recurrence.