What causes leukemia?

Leukemia begins when cells in the bone marrow malfunction and interrupt normal production of blood cells. The precise cause of this malfunction is unknown, but certain risk factors have been identified. The malfunctioning cells continue to grow and divide, unlike healthy cells, which eventually die and are replaced. Furthermore, the cancerous cells, which would have otherwise become healthy red or white blood cells or platelet cells, do not function properly once released into the blood stream and soon begin to upset the regular balance of blood cells.

Leukemias have various etiologies, and can be chronic or acute. Both these entities may result from various chromosomal translocations already inherent in the bone marrow, which allow malignant clones to grow uncontrollably until a critical level is reached, requiring treatment. Specifically, acute myeloid leukemia may be triggered after a history of myelodysplasia in the bone marrow, or may result from specific DNA aberrations induced by previous chemotherapy in a small percentage of patients. Attempts to identify environmental factors as causative for acute leukemias, for example, have also shown a link between prolonged exposure to chemical solvents, petroleum, benzenes, pesticides, ionizing radiation and the development of acute myeloid leukemia. Often, however, no identifiable cause can be found, and thus no routine screening has been set as a standard for surveillance.