Histone deacetylase inhibitors (HDACis), as important reagents in epigenetic therapy, have shown promising effect in clinical trials for the treatment of human malignancies.18 Suberoylanilide hydroxamic acid (SAHA) and valproic acid (VPA) are potent HDACi drugs that have been approved by the United States Food and Drug Administration to treat cutaneous T-cell lymphoma and epilepsy, respectively. Both SAHA and VPA display antitumor activity in vivo with a favorable pharmacological profile and well-tolerated side effects.19, 20 In addition, HDACis might sensitize malignant cells to NK cell recognition depending on NKG2D–NKG2DL signaling.21, 22 These data suggest that HDACis may serve as a new and tumor-selective drug class by enhancing immune surveillance in the treatment of BC.