NOTCH1 and renal cell carcinoma: In the present study, we have demonstrated that miR-138–2 is NOTCH1-specific microRNA, and its expression is directly down-regulated by HES1. Moreover, our results clearly showed that miR-138 efficiently impairs the translation of major members of NOTCH1 signaling pathway. Collectively, our current findings emphasized the importance of the key regulatory role of HES1-miR-138-NOTCH1 regulatory feedback loop in NOTCH1 signaling pathway, and also strongly suggest that miR-138 is an attractive molecular target for the development of an alternative therapeutic strategy to treat RCC patients.