MicroRNA-15a expression measured in urine samples as a potential biomarker of renal cell carcinoma

Currently, there is no accurate diagnostic molecular biomarker for renal cell carcinoma (RCC). The aim of this study was to assess the expression of microRNA-15a (miR-15a) in urine of patients with RCC and to evaluate its potential as a diagnostic molecular biomarker. In total, 67 patients with solid renal tumors were enrolled: clear-cell RCC (ccRCC, n = 22), papillary RCC (pRCC, n = 16), chromophobe RCC (chRCC, n = 14), oncocytoma (n = 8), papillary adenoma (n = 2) and angiomyolipoma (n = 5). MiRNA-15a expression levels measurement in urine were performed using qPCR. Urine of 15 healthy volunteers without kidney pathology was used as control. We observed a difference in mean miR-15a expression values in groups of pre-operative patients with RCC, benign renal tumors and healthy persons (2.50E-01 +/- 2.72E-01 vs 1.32E-03 +/- 3.90E-03 vs 3.36E-07 +/- 1.04E-07 RFU, respectively, p < 0.01). There was no difference in miR-15a expression between ccRCC, pRCC and chRCC (p > 0.05). Direct association between RCC size and miR-15a expression values was obtained (Pearson correlation coefficient-0.873). On the 8th day after nephrectomy, mean expression value in patients with RCC decreased by 99.53% (p < 0.01). MiR-15a expression differentiated RCC from benign renal tumors with 98.1% specificity, 100% sensitivity at a cut-off value of 5.00E-06 RFU, with AUC-0.955. MiR-15a expression measured in urine may be used as diagnostic molecular biomarker for RCC.