All types of blood cells are produced by bone marrow. Bone marrow is the spongy tissue inside the large bones of the body. The bone marrow produces red blood cells (which carry oxygen and other materials to all tissues of the body), white blood cells (which fight infection) and platelets (which help blood to clot).
In leukemia, the process of bone marrow controlling the production of normal cells breaks down. The bone marrow then begins producing large numbers of abnormal cells of only one type, usually one of the white cells. These abnormal, immature cells, called blasts, then flood the blood stream and lymph system, and may invade vital organs such as the brain, testes, ovaries or skin.
Leukemia can be acute (progressing quickly with many immature blasts) or chronic (progressing slowly with more mature-looking cancer cells). Acute myeloid leukemia progresses quickly.
If your child has symptoms of leukemia, the doctor may order blood tests to count the number of each of the different kinds of blood cells. If the results of the blood tests are not normal, a bone marrow biopsy may be performed. During this test, a needle is inserted into a bone in the hip and a small amount of bone marrow is removed and examined, enabling the doctor to determine the type of leukemia and the best treatment plan.