KMT2A and leukemia: In this study, we identified a set of lncRNAs acting as lnc-eRNAs that are activated in MLL leukemia through a HOXA initiation-BRD4 transcriptional activation mechanism, by which the MLL fusion downstream HOXA cluster initiates enhancer establishment, and the epigenetic reader BRD4 cooperates with the coregulator MLL fusion oncoprotein to induce enhancer transcription.