acute childhood leukemia, a progressive, malignant disease of the blood-forming tissues. It is characterized by the uncontrolled proliferation of immature leukocytes and their precursors, particularly in the bone marrow, spleen, and lymph nodes. It is the most frequent cancer in children, with a peak onset occurring between 2 and 5 years of age. Cure rates are high. See also acute lymphocytic leukemia, acute myeloid leukemia, leukemia.
