What is (are) Childhood Acute Lymphoblastic Leukemia ?
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.    - Past treatment for cancer and certain genetic conditions affect the risk of having childhood ALL.    - Signs of childhood ALL include fever and bruising.    - Tests that examine the blood and bone marrow are used to detect (find) and diagnose childhood ALL.    - Certain factors affect prognosis (chance of recovery) and treatment options.
                 
                
                    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).
                    Childhood acute lymphoblastic leukemia (also called ALL or acute lymphocytic leukemia) is a cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if it is not treated.     ALL is the most common type of cancer in children.
                
                
                    Leukemia may affect red blood cells, white blood cells, and platelets.
                    In a healthy child, the bone marrow makes blood stem cells (immature cells) that become mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell.   A myeloid stem cell becomes one of three types of mature blood cells:         -  Red blood cells that carry oxygen and other substances to all tissues of the body.    -  Platelets that form blood clots to stop bleeding.    -  White blood cells that fight infection and disease.         A lymphoid stem cell becomes a lymphoblast cell and then one of three types of lymphocytes (white blood cells):         -  B lymphocytes that make antibodies to help fight infection.    -  T lymphocytes that help B lymphocytes make the antibodies that help fight infection.    -  Natural killer cells that attack cancer cells and viruses.         In a child with ALL, too many stem cells become lymphoblasts, B lymphocytes, or T lymphocytes. The cells do not work like normal lymphocytes and are not able to fight infection very well. These cells are cancer (leukemia) cells. Also, as the number of leukemia cells increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may lead to infection, anemia, and easy bleeding.   This summary is about acute lymphoblastic leukemia in children, adolescents, and young adults. See the following PDQ summaries for information about other types of leukemia:         -  Childhood Acute Myeloid Leukemia/Other Myeloid Malignancies Treatment     -  Adult Acute Lymphoblastic Leukemia Treatment     -  Chronic Lymphocytic Leukemia Treatment     -  Adult Acute Myeloid Leukemia Treatment     -  Chronic Myelogenous Leukemia Treatment     -  Hairy Cell Leukemia Treatment