OUTLINE: Archived bone marrow samples are analyzed for CD33+ progenitors, X-chromosome inactivation, and somatic mutations (t(8;21), inv(16), FLT3/ITD, NPM1, CEBPA, KIT) by fluorescence-activated cell sorting, long-term culture in hypoxic condition in cytokine-containing liquid media, and flow cytometry. Results are then compared with each patient clinical data.