To examine how CLL cells cope with the limited activities of epigenetic regulators, we isolated and cultured CLL and non-CLL B cells from Eμ-Tcl1 mice as well as B cells from healthy mice and treated them with inhibitors against the downregulated epigenetic factors HDAC3A, HDAC2A, KDM4A, and eIF4E in a dose–response assay. Here, KDM4A is linked to B-cell chronic lymphocytic leukemia.