CREB1 and glioblastoma: cAMP response element-binding protein 1 (CREB1) directly binds to the promoter of miR-23a to promote its expression, while STAT3 indirectly induces miR-23a expression.40 Given that both CREB1 and STAT3 are up regulated in glioma,40,41 transcription factor-dependent upregulation of miR-23a might contribute to the aggressive invasion of GBM.