The present invention is based on the findings that a novel function for miR142-3p in the regulation of Sox2, adenylyl cyclase 9 (AC9), and CD133 expressions, and consequently the overall stemness of recurrent GBM cells as well as CSCs, and that miR142-3p modulated tumor-initiating properties in recurrent GBM. The present invention consequently supports the development of novel miRNA-based strategies for brain tumor treatment.