ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Childhood Acute Lymphoblastic Leukemia (ALL). Use the menu to see other pages. Think of that menu as a roadmap for this complete guide.
Leukemia is a cancer of the blood. Leukemia begins when healthy blood cells change and grow uncontrollably. Acute lymphoblastic leukemia (ALL) is a cancer of the lymphocytes, which are a type of white blood cell involved in the body’s immune system. ALL is the most common type of cancer in children.
About lymphocytes and lymphoblasts
Lymphocytes are made in the bone marrow, which is the spongy, red tissue in the inner part of the large bones. Lymphocytes are found in the blood, lymph nodes, and spleen. Healthy lymphocytes fight bacterial and viral infections. In people with ALL, new lymphocytes do not develop into mature cells, but stay as immature cells called lymphoblasts.
When a child has ALL, the lymphoblasts fill the bone marrow and crowd out other normal cells, preventing the production of red blood cells, many other types of normal white blood cells, and platelets. If the bone marrow is not functioning correctly, the child may experience anemia, easy bruising, bleeding, or infection.
Anemia is from too few red blood cells. Red blood cells are cells that carry oxygen to tissues around the body. Anemia can lead to fatigue, irritability, sleepiness, paleness, shortness of breath, and a rapid heartbeat.
Bruising or bleeding from injuries may occur more easily because the blood cannot clot normally when the platelet count is low. Platelets are cells that help blood to clot.
Infection may occur more often if the blood has too few normal white blood cells. White blood cells are cells that fight infection. Many types of white blood cells are needed to fight infections caused by different germs.
The leukemic lymphoblasts may also collect in the child’s lymph nodes and cause them to swell. Lymphoblasts may also spread to other organs, including the skin, liver, spleen, the spinal fluid, a girl’s ovaries, and a boy’s testicles.
This section is about ALL in children, sometimes called childhood ALL or pediatric ALL. Learn more about acute lymphocytic leukemia in adults in a different guide on this website.
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The next section in this guide is Statistics. It helps explain the number of children who are diagnosed with acute lymphoblastic leukemia and general survival rates. Use the menu to choose a different section to read in this guide.