It has also been shown that epigenetic modulation of genes such as retinoblastoma 1 (Rb1) may alter the reserves and function of MDSCs.96 It is therefore interesting to investigate whether epigenetic regulators including the hypomethylating agents widely used in the treatment of MDS/AML, have also an impact on the MDSC component of the BM microenvironment. This evidence concerns the gene RB1 and acute myeloid leukemia.