MicroRNA promoter methylation: a new tool for accurate detection of urothelial carcinoma

Background: Urothelial carcinoma (UC) is the most common cancer affecting the urinary system, worldwide. Lack of accurate early detection tools entails delayed diagnosis, precluding more efficient and timely treatment. In a previous study, we found that miR-129-2 and miR-663a were differentially methylated in UC compared with other genitourinary tract malignancies. Here, we evaluated the diagnostic performance of those microRNAs in urine. Methods: Promoter methylation levels of miR-129-2 and miR-663a were assessed, using real-time quantitative methylation-specific PCR, in UC tissue samples (using normal urothelium as control) and, subsequently, in urine samples from UC and other genitourinary malignancies. Diagnostic and prognostic performances were evaluated by receiver operator characteristics curve and survival analyses, respectively. Results: Promoter methylation levels of both microRNAs were significantly higher in UC tissue samples compared with normal urothelium. In urine, the assay was able to distinguish UC from other genitourinary tract carcinomas with 87.7% sensitivity and 84% specificity, resulting in 85.85% overall accuracy. Conclusions: This panel of miRNAs promoter methylation accurately detects UC in urine, comparing well with other promising epigenetic-based biomarkers. This may constitute the basis for a non-invasive assay to detect UC.