For example, CRA-024781 (ABEXINOSTAT) with high selectivity of HDAC6 and 8, entinostat with high selectivity of HDAC1 and 3 and the pan HDAC inhibitor CI-994 have all entered the phase III clinical trial for the treatment of renal cell carcinoma, advanced breast cancer, and lung cancer.377,378 Many others are in the phase I–II clinical trials for the treatment of solid tumor or leukemia.379–383 Besides, some compounds showed potential effectiveness in treating neurological diseases, metabolic diseases or inflammatory and infectious disease and are tested in clinical trials (Table 3). The gene discussed is HDAC1; the disease is breast cancer.