Leukemia is cancer of the blood cells. The blood is made up of fluid called plasma and three types of cells. Each type has special functions. The red blood cells give blood its color. Blood cells are formed in the bone marrow, the soft, spongy center of bones.
Some blasts stay in the marrow to mature.
Some travel to other parts of the body to mature. Normally, blood cells are produced in an orderly, controlled way, as the body needs them. This process helps keep us healthy. When leukemia develops, the body produces large numbers of abnormal blood cells. In most types of leukemia, the abnormal cells are white blood cells.