blastic transformation, a late stage in the progress of chronic granulocytic leukemia. The leukemic cells become more undifferentiated and morphologically and genetically more abnormal, with more aggressive growth patterns. Signs of anemia and blood platelet deficiency are present, and half of the blood cells in the bone marrow are immature forms. Blastic transformation indicates that resistance to therapy has developed in the patient who has entered a terminal stage of leukemia.
