In order to obtain a first indication of the similarities and differences in the cistromes regulating gene expression patterns in t(8;21) and t(3;21) AML we mapped the accessible chromatin landscape by identifying all DHSs in purified CD34+ leukemic blast cells of two t(3;21) and two t(8;21) AML patients, two sets of normal CD34+ progenitor cells purified as mobilized peripheral blood stem cells (PBSCs) from peripheral blood, and a t(3;21) cell line derived from a CML patient in blast crisis (SKH-1; Mitani et al., 1994)). Here, CD34 is linked to acute myeloid leukemia.