Expression of miR-486 is a potential prognostic factor after nephrectomy in advanced renal cell carcinoma

Renal cell carcinoma is the most frequently occurring neoplasm in the adult kidney, leading to poor prognosis. Therefore novel biomarkers are required for the prediction of early metastasis following nephrectomy. The aim of the present study was to investigate whether or not expression levels of miR-486, detected in RNA isolated from formalin-fixed paraffin-embedded tissue sections, can predict prognosis for patients with renal cell carcinoma (RCC). Expression levels of miR-486 were measured by quantitative reverse transcriptase-polymerase chain reaction in 150 RCC cases. Expression of miR-486 in RCC samples was ∼2.7-fold higher than in corresponding non-neoplastic kidney samples (P<0.0001). In stage III and IV RCC cases (n=46), a high miR-486 expression in tumors was associated with worse cancer-specific mortality, independent of clinical covariates, including TNM staging (P=0.0064). In addition, miR-486 expression tended to be associated with cancer-specific mortality in stage III and IV RCC patients who were not treated with interferon-α (Kaplan-Meier analysis, n=14, P=0.0574). These results suggest that miR-486 is a promising biomarker to identify poor prognosis in RCC patients. As expression of miR-486 was measured from formalin-fixed paraffin-embedded (FFPE) samples, this study demonstrated that measurement of miR-486 may be readily translated into clinical applications.