MiR-378a-5p acts as a tumor suppressor in renal cell carcinoma and is associated with the good prognosis of patients.

Renal cell carcinoma (RCC) is a common cancer that accounts for about 1.6% of all malignancies. Accumulating evidence has shown that miRNAs may play important roles in the development of cancers and that these same miRNAs may serve as diagnostic and prognostic biomarkers. The role of the miRNA miR-378a-5p in RCC, however, has been largely unexplored. In our study, we have demonstrated that miR-378a-5p expression was decreased in renal tissues and in RCC cell lines compared with corresponding expression levels in normal renal tissues and in the 293-T cell line. Functional studies in two RCC cell lines (ACHN and 786-O) have indicated that miR-378a-5p overexpression attenuated cell proliferation, migration, and invasion while promoting cell apoptosis. Inhibition of miR-378a-5p expression, on the other hand, promoted cell proliferation, migration, and invasion while reducing cell apoptosis. Additionally, in 42 cases of renal cancer formalin-fixed paraffin-embedded specimens, patients with higher expression levels of miR-378a-5p had significantly longer overall survival rates (P<0.05) than patients with lower miR-378a-5p expression levels. Thus, in this study, we have shown that miR-378a-5p can serve as a tumor suppressor and a potential prognostic biomarker in RCC.