According to WebMD, "Leukemia is cancer of the blood cells", and "there are several different types of leukemia. In general, leukemia is grouped by how fast it gets worse and what kind of white blood cell it affects."
- It may be acute or chronic. Acute leukemia gets worse very fast and may make you feel sick right away. Chronic leukemia gets worse slowly and may not cause symptoms for years.
- It may be lymphocytic or myelogenous. Lymphocytic (or lymphoblastic) leukemia affects white blood cells called lymphocytes. Myelogenous leukemia affects white blood cells called myelocytes.