Leukemia is a type of cancer in which the number of white blood cells in either the blood or bone marrow increases abnormally. Leukemia may get worse quickly (acute leukemia) or slowly (chronic leukemia).

Symptoms of leukemia include:

• Low numbers of red blood cells (anemia). A person with leukemia may feel tired or weak or have a pale appearance.
• Low numbers of the cells that help blood to clot (platelets). The person may notice that he or she bruises more easily.
• Swollen glands (lymph nodes) and an enlarged spleen and liver.
• Frequent infections.
• Unexplained fever, pain, or night sweats.

In some forms of leukemia a person may have few or no symptoms.

There are four main types of leukemia: acute lymphoblastic (ALL), acute myelogenous (AML), chronic lymphocytic (CLL), and chronic myelogenous (CML). Each type of leukemia has subtypes. A doctor determines which type of leukemia is present by examining blood cells under a microscope.

Treatment for leukemia depends on the specific type of leukemia and the stage of the disease. It may include blood transfusions, chemotherapy, radiation, or a stem cell transplant.