Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Childhood Acute Lymphoblastic Leukemia ?
    ### Response:
    Key Points
                    - Childhood acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many immature lymphocytes (a type of white blood cell).    - Leukemia may affect red blood cells, white blood cells, and platelets.
    