To investigate whether HF can enhance drug cytotoxicity and reverse resistance, AML cells were treated with HF, idarubicin (IDA), cytarabine (Ara-C), hypomethylation agent decitabine (DAC), HDAC inhibitor tucidinostat (Tuc), or a combination of HF and these drugs. This evidence concerns the gene HDAC9 and acute myeloid leukemia.