About Acute Lymphoblastic Leukemia (ALL)
Acute lymphoblastic leukemia (also called acute lymphocytic leukemia, or ALL) in children is cancer of the blood that starts in the bone marrow and spreads to the bloodstream. Leukemia starts in the bone marrow, the spongy internal part of bones where new blood is made. The term leukemia comes from Greek words for white and blood, because ALL affects white blood cells.
Leukemia develops because of a mutation in a white blood cell that causes it to multiply uncontrollably. These mutated white blood cells, called “blasts” take over the bone marrow and crowd out normal blood cells. One blast soon generates billions of other blasts, with a total of about a trillion leukemia cells typically present in the body at the time of diagnosis.
ALL is the most common children’s cancer, accounting for 25% of all cancers in children under the age of 15. There are over 3,000 new cases of ALL diagnosed in children and adolescents (0-19 years old) in the United States each year.