EZH2 and diffuse large B-cell lymphoma: Therefore, we treated the refractory DLBCL cells, Karpas-422 and SUDHL4, with DMSO (vehicle), the HDAC1,2 selective inhibitor alone (ACY-957), the EZH2 inhibitor alone (DZNep) or a combination of both these inhibitors (ACY-957+DZNep).