Leukemia* is cancer that starts in the tissue that forms blood. Most blood cells develop from cells in the bone marrow called stem cells. In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work. The four main types of leukemia are:
- Acute lymphoblastic leukemia (ALL)
- Acute myelogenous leukemia (AML)
- Chronic lymphocytic leukemia (CLL)
- Chronic myelogenous leukemia (CML)
There is no standard staging system for leukemia. The disease is described as untreated, in remission, or recurrent.
*Leukemia can be also spelled Leukaemia
SEER Cancer Stat Facts: Leukemia. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/leuks.html