To explore the roles of EP300 and CREBBP in MLL-r AML cells, EP300 or CREBBP was knocked out respectively by CRISPR-Cas9 mediated sgRNA targeting (Fig. 2A and Additional file 1: Fig. S2A) in both MLL-r and MLL wild-type cell lines. The gene discussed is CREBBP; the disease is acute myeloid leukemia.