What Causes Leukemia?


What makes one person more likely to develop leukemia than another person?  Unfortunately the specific cause of leukemia is unknown.  There are several suspected factors that may cause leukemia, but even these factors are not absolute indicators of developing leukemia.  Even though a person may have been exposed to one or more of the following risk factors, it does not necessarily mean they will develop leukemia.   In fact, most people who develop the disease have not been exposed to any risk factors at all—the direct cause of leukemia is still unknown.


Suspected Environmental Risks:


* Smoking--about 20 percent of adult acute leukemia cases are related to smoking.

Three Mile Island

site of nuclear reactor accident picture provided by CDC

* High doses of radiation, produced by an atomic bomb or a nuclear reactor accident.

* Long-term exposure to benzene, found in gasoline, which causes a twenty times higher risk of developing acute mylogenous leukemia.

* Exposure to electromagnetic fields (a type of low-energy radiation that comes from power lines and electric appliances).

*Treatment for other types of cancer by a combination of certain chemotherapy drugs and radiation therapy.

*Parental exposure to radiation before conception or during early fetal development.






Genetic Risks:

*  Myelodysplstidic syndrome--a pre-leukemia condition.

*  Chromosome damage—rare genetic syndromes put people at a higher risk.

*  Immune system deficiencies--People are more at risk when they have a decreased ability to resist foreign cells.

*  Downs syndrome--children born with Downs are twenty times more likely to develop acute leukemia.

*  Chronic Myelogenous leukemia--a chromosomal disorder.  The Philadelphia Chromosome hooks up to a different chromosome than it is supposed to, making the body unable to know when to stop producing white blood cells.




Viral risks:

*  Viruses may cause leukemia in animals, but in humans this only occurs with rare types of leukemia—very uncommon.

*  Common forms of leukemia are not contagious.


Feline leukemia virus infection was until recently, the most common fatal disease of cats.  Extensive studies have provided no conclusive evidence of Feline Leukemia Virus related diseases in humans.