Acute Lymphocytic Leukemia (ALL)

Risk factors for different types of cancer are those traits that increase the likelihood that an individual will develop disease. Risk factors include certain kinds of behavior such as smoking, inherited (genetic) traits, and exposure to cancer-causing agents in the environment. There is only a very small chance that a person who has one of the few known risk factors for ALL will develop the disease.

People who are exposed to high doses of radiation (from the explosion of an atomic bomb, working in an atomic weapons plant, or a nuclear reactor accident) have a heightened risk of developing leukemia. This is also true of people who are exposed over long periods of time in the workplace to high levels of solvents such as benzene.

People who have a myelodysplastic syndrome -- a preleukemia condition -- or who have rare genetic syndromes such as Down's syndrome, Fanconi's anemia, ataxia-telangiectasia, and Bloom's syndrome have a higher risk of developing leukemia.

Many people with one or more of these risk factors never develop leukemia. And most of the people who do develop ALL have no risk factors at all. Scientists do know that most leukemias are associated with specific gene mutations -- alterations in the DNA of the diseased cells -- but, in most cases, it is not clear what causes those mutations.