It was demonstrated that an increased levels of acetylation in histone 3 lysine 27 (H3K27) was detected on the CD26 promoter of each myeloma cell line after exposure to HDACi, suggesting its part of roles in the mechanisms involved in HDACi-dependent CD26 promoter activation in myeloma cells (Fig. 5A). The gene discussed is DPP4; the disease is plasma cell myeloma.