Evaluation of the methylation status of specific promoter regions of p15, p16, E-cadherin and RARβ genes, core and linker histones distribution, histones H3 and H4 modifications (H3K4Me3, H3K9Ac, H3K9Ac/S10Ph and H4 hyperAc) during hematopoietic cell differentiation can provide a new basis for identifying chromatin epigenetic modulators as targets in the regulation of hematopoiesis and for leukemia induced differentiation therapy. This evidence concerns the gene RARB and leukemia.