DefinitionAcute lymphocytic leukemia (ALL) is a fast-growing cancer in which the body produces a large number of immature white blood cells (lymphocytes). These cells are found in the blood, bone marrow, lymph nodes, spleen, and other organs.Alternative NamesALL; Acute childhood leukemia; Cancer - acute childhood leukemia (ALL); Leukemia - acute childhood (ALL)Causes, incidence, and risk factorsALL makes up 80% of childhood acute leukemias. Most cases occur in children ages 3 - 7. The disease may also occur in adults.In acute leukemia, cancerous cells multiply quickly and replace normal cells. Cancerous cells take over normal parts of the bone marrow, often causing low blood counts .Most cases of ALL have no obvious cause. However, the following may play a role in the development of leukem