CASP9 and acute myeloid leukemia: We first confirmed the effect of quercetin in apoptotic induction in AML cells, basing on the following observations: 1) the typical apoptotic cell death in AML cell after quercetin treatment, which can be reversed by both pan-caspase inhibitor and specific caspase inhibitors, specific for caspase 8 and caspase 9 (Figures 2B–D); 2) the dose-dependent cleavage of caspase proteins and PARP (Figure 2A), another hallmark for apoptotic cell death.