What type of leukemia involves immature white blood cells: lymphocytic or myeloid?

Leukemias: Acute leukemias are those with large numbers of immature cells that grow quickly. They can be either myeloid or lymphoid in lineage. Chronic leukemias have more mature cells, a longer course, but can also be myeloid or lymphoid. A hematologist/oncologist is generally the treating physician, and a hematopathologist is the one who give the specific syping.