This frequency corresponds to the approximate 20% response rates to HDAC inhibitors observed in unselected patients with DLBCL, providing a biologic rationale for a clinical trial using CREBBP/EP300 mutation as a genomic biomarker to select DLBCL patients for treatment with the HDAC inhibitors (NCT02282358)19. The gene discussed is HDAC9; the disease is diffuse large B-cell lymphoma.