HDAC9 and acute lymphoblastic leukemia: Consequently, several epigenetic drug classes, including DOT1L histone methyltransferase, BET protein, and histone deacetylases (HDAC) inhibitors, have shown promising results in MLL‐rearranged ALL animal models [12, 13, 14, 15, 16], providing preclinical rationales for their implementation in current and future clinical trials [17].