text: Learn more about leukemia by taking this quiz, based on information from the Leukemia and Lymphoma Society (LLS) and the National Cancer Institute (NCI).
  1. A person with leukemia produces abnormal white blood cells that over time crowd out normal white and red blood cells, and platelets.
  Although the abnormal white blood cells function almost normally, they eventually become so numerous that they interfere with the function of the normal blood cells, the NCI says.
  The disease is further divided by the types of white blood cells it affects. Myeloid leukemia affects the myeloid cells; lymphocytic leukemia affects the lymphoid cells, the NCI says. The names of the four common types of leukemia are acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL).
  According to the American Cancer Society, men have a lifetime risk of 1 in 250; women's risk is 1 in 300. AML is one of the most common types of leukemia in adults, although it is less common in children.
  In most cases, the cause of leukemia is not known, but certain environmental and genetic factors appear to increase the risk for the disease, the NCI says. These include not only exposure to benzene, but also exposure to high levels of radiation, either through wartime or disaster, or through medical radiation treatment; chemotherapy; smoking; and Down syndrome and other genetic diseases caused by abnormal chromosomes. In addition, the human T-cell leukemia virus-1 causes a rare type of chronic lymphocytic leukemia (CLL), and the rare blood disease myelodysplastic syndrome raises the risk for AML.
  This symptom is caused by a low level of blood platelets, which normally help the blood to clot. It may also indicate other disorders, however. Other possible symptoms, according to the NCI, include fever or night sweats; frequent infections; lingering fatigue; headaches; pain in the bones or joints; swelling or discomfort in the abdomen, from an enlarged spleen; swollen lymph nodes; pallor; and weight loss. Not everyone with leukemia has major symptoms; diagnosis depends on looking at the cells in the bone marrow. Many times, people with leukemia are diagnosed after a routine health checkup.
  It is more likely to occur in children under age 10. Although the cause of ALL isn't known, it occurs more often in developed countries and in families with higher socioeconomic standing. Besides affecting children under age 10, it also affects older adults.
  This defect, called the Philadelphia chromosome, occurs only in the stem and blood cells, not the rest of the cells in the body. In CML, parts of chromosomes 9 and 22 switch places, an exchange called a translocation, the LLS says. Researchers do not know why this translocation occurs. This same translocation occurs in a small number of acute lymphocytic leukemias, as well. Other chromosome changes are seen in some other types of leukemia, but these changes are not seen in all cases.
  8. A person with acute leukemia is considered cured if no evidence of the disease exists one year after treatment.
  The time frame is five years. The goal of treatment for acute leukemia is complete remission: no trace of the disease. Treatment for both chronic and acute leukemia may involve chemotherapy, targeted therapy, biological therapy, radiation therapy or a bone marrow transplant, the NCI says. People with an enlarged spleen may need to have their spleen removed. People with a chronic form of leukemia may not need treatment right away. When treatment is needed, it usually can control the disease and symptoms. Chronic leukemia usually can't be cured, but it can often be controlled for long periods of time.