Leukemias and the related disorders myelodysplastic syndrome and myeloproliferative diseases represent a wide group of bone marrow stem cell malignancies. Some patients can be cured with chemotherapy or by allogeneic stem cell transplantation. However, standard treatment approaches are not effective for patients who become refractory to chemotherapy, those who relapse after transplantation and those with progressive disease. The management of such patients remains unsatisfactory and requires new treatment approaches other than chemotherapy.