To verify this hypothesis, AML cell line U937, KG-1 and THP-1 cells were treated with different concentrations of HHT for 24 hours and cell proliferation was measured by MTT assay, the IC50 value of these cell lines were: U937, 8.02 ng/ml; THP-1, 35.5 ng/ml; KG-1, 103.3 ng/ml (Supplementary Figure 1A), and these IC50 values are consistent with the smad3 protein levels of the cell lines (Supplementary Figure 1B). This evidence concerns the gene SMAD3 and acute myeloid leukemia.