In particular, we studied BRCA1 regulation by promoter hypermethylation in therapy-related AML (t-AML), as drugs and radiation have been shown to induce DNA hypermethylation, and BRCA1 has an important role in the repair process of DNA damage, induced by these agents (Issa et al, 1996; Kennedy et al, 2004; Pogribny et al, 2004). This evidence concerns the gene BRCA1 and acute myeloid leukemia.