One identified compound ITF2357 is a potent HDAC inhibitor that was reported to have antitumor activity.[57] The roles of HDAC inhibitors in anti‐tumor immunity have been emerging, including the upregulation of genes involved in the antigen presentation and costimulatory molecule expression in cancer cells, and altering the activity of immune cells via cytokine and chemokine secretion.[58] The development of potent inhibitors of BET proteins, which target bromodomains, has been a feasible approach to suppress oncogenic networks within tumors. This evidence concerns the gene HDAC9 and cancer.