Overview
Leukemia is a type of cancer that arises in the blood and bone marrow.
Bone marrow, a soft type of tissue that is found in the center of some bones, is the body's "blood factory." It produces immature cells that eventually develop into new blood cells.
Blood cells perform a variety of jobs. Red blood cells deliver oxygen to tissues throughout the body; white blood cells defend the body against invading bacteria. Platelets help the blood to clot.
Leukemia occurs when immature white blood cells, called blasts, become damaged and fail to go through a normal life cycle. The result is a large number of diseased white blood cells. In some cases the abnormal cells are immature forms called blasts, while in other cases they are more mature forms of blood cells. The abnormal cells are not able to perform all of their usual duties in the body and may also crowd out other types of blood cells, leading to infections, bleeding, anemia, and other symptoms of leukemia.
The type of leukemia diagnosed depends on which type of white blood cell is affected. Possible diagnoses include acute lymphocytic leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, and hairy cell leukemia.
About 30,800 people will be diagnosed with leukemia this year.
