For example, MERCK60 is useful to eliminate B-cell-derived tumors by not further specified mechanisms.24 Other isoform-specific HDACi such as the HDAC3 inhibitor RGFP966 or the HDAC10 inhibitor PZ48, target the β-catenin‒MYC or the MYC‒POLD1 axes in AML and ALL cells, respectively.34,35 A key task to optimally exploit the arsenal of HDACi is the identification of particularly vulnerable tumor entities and the identification of biomarkers that indicate the efficiency of HDACi in such cancers. This evidence concerns the gene POLD1 and acute myeloid leukemia.