HDAC4 and acute myeloid leukemia: Quercetin induces apoptosis in vivo in human xenograft acute myeloid leukemia (AML) and in vitro in leukemia cell lines by reducing nuclear translocation of Nrf2, inducing proteasomal degradation of Nrf2 and upregulating the histone deacetylase HDAC4, which leads to upregulation of pro-apoptotic miRNAs.