What Is It?
Acute lymphocytic leukemia (ALL) is a cancer of the body's blood-making system. (It is also known as acute lymphoblastic leukemia and acute lymphoid leukemia.) The word "acute" refers to the fact that the disease can progress quickly. "Lymphocytic" means that the cancer develops from lymphocytes, a type of white blood cell.
Bone marrow, the soft inner part of bones, makes cells that circulate in the blood. They include white blood cells, red blood cells, and platelets. The two major types of white blood cells are myeloid cells and lymphoid cells. Lymphocytes form from lymphoid cells.
Normally, the bone marrow makes three types of infection-fighting lymphocytes:
In ALL, the bone marrow makes too many immature lymphocytes. These lymphocytes, called blasts, contain abnormal genetic material. They cannot fight infections as well as normal cells. In addition, because these lymphocytes multiply quickly, they crowd out healthy white blood cells, red blood cells, and platelets in the blood and bone marrow. This may lead to infection, anemia, and easy bleeding.
ALL typically invades the blood quickly. It can involve other parts of the body, such as the lymph nodes, liver, spleen, brain and spinal cord (central nervous system), and testicles (testes).
Although it is rare, ALL is the most common cancer in children. It can affect children of any age, but most are diagnosed between 2 and 4 years old.
A few factors may increase a child's risk of developing ALL. These include
Having one or more of these risk factors does not mean your child will develop ALL. Many children with the disease have no risk factors.
ALL has several subtypes. Subtypes depend on
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