AFDN and leukemia: To interrogate the BETi-resistance mechanism in leukemia models, we carried out an unbiased screen using the OCI-AML2 cell line (carrying the KMT2A-AF6 fusion) stably expressing Cas9 and a whole-genome CRISPR sgRNA library (H3, Addgene #133914) targeting more than 19,000 human genes.