Poor prognosis of a subtype of this disease and its potential precursors are linked to a deletion in chromosome 7’s long arm that manifests as a monosomy. Like its MPN and MDS precursors, a subtype of this disease may present (15[1])with cytoplasmic granules and needle-like Auer rods. A chemotherapeutic 7+3 regimen can treat a subtype of this disease, another subtype of which is treated by orally administering 6MP and methotrexate as part of its maintenance therapy. Imatinib treats a form of this disease by inhibiting a (*) BCR-ABL fusion protein originating from the Philadelphia chromosome. Subtypes of this disease can be described as acute or chronic and myeloid or lymphocytic. An abnormally high white blood cell count characterizes the chronic form of this disease. For 10 points, name this most common pediatric cancer which, like myelomas and lymphomas, may require a bone marrow transplant. ■END■