Leukemia Chronic Myelogenous Risk Factors

Understanding what causes leukemia is vital if doctors hope to develop new and effective treatments for the disease. Few chronic myelogenous leukemia (CML) risk factors exist, making it difficult to predict who is in danger of developing CML. While a genetic abnormality called the Philadelphia chromosome triggers the over-production of white blood cells that causes CML, it is not clear what causes the initial gene mutation.

Chronic Myelogenous Leukemia Risk Factors

Chronic myelogenous leukemia risk factors are not as well understood as those associated with some other cancers. Doctors do know that the risk of developing CML increases with age, and appears to be slightly higher in men than women.

Exposure to radiation explains what causes leukemia in a small percentage of CML cases. For example, survivors of the atomic bombs that struck Hiroshima and Nagasaki had higher than normal rates of leukemia.

Previous radiation therapy for other cancers is another identifiable chronic myelogenous leukemia risk factor. However, any risk of leukemia associated with radiation therapy is very small and usually outweighed by the benefits of treating the initial cancer.

Other chronic myelogenous leukemia risk factors exist, although their impact on CML rates is often very low. Cancer Research UK (2010) reports HIV/AIDS patients have rates of leukemia three times greater than the general population and that immune-suppressing medication required after organ transplants doubles the risk of leukemia.

Other chronic myelogenous leukemia risk factors include working directly with pesticides and benzene, a compound found in gasoline and used in rubber manufacturing. People living with ulcerative colitis also have an increased risk of developing leukemia. Being overweight also seems to slightly increase a person’s risk of developing CML.

Factors That Don’t Increase CML Risk

Risk factors associated with some other cancers, such as family history, diet, smoking and infections, do not appear to influence a person’s risk of developing CML.

What Causes Leukemia? The Philadelphia Chromosome

So what causes leukemia? In the case of chronic myelogenous leukemia, the culprit appears to be a genetic abnormality known as the Philadelphia chromosome.

The Philadelphia chromosome is not hereditary. Instead, the Philadelphia chromosome develops after birth. Virtually all chronic myelogenous leukemia cases involve the Philadelphia chromosome.

The Philadelphia chromosome results in the overproduction of a protein called BCR-ABL (a tyrosine kinase), which in turn triggers production of abnormal white blood cells. The abnormal cells also contain the Philadelphia chronmosome, resulting in a steady accumulation of abnormal white blood cells that eventually crowd out healthy blood cells.


American Cancer Society. (2010). Leukemia — Chronic myeloid (myelogenous) overview. Retrieved September 24, 2010, from http://www.cancer.org/Cancer/Leukemia-ChronicMyeloidCML/OverviewGuide/leukemia-cml-overview-what-causes.

Cancer Research UK. (2010). Chronic myeloid leukaemia (CML) risks and causes. Retrieved September 24, 2010, from http://www.cancerhelp.org.uk/type/cml/about/chronic-myeloid-leukaemia-risks-and-causes#cml.

Mayo Clinic Staff. (2008). Chronic myelogenous leukemia. Retrieved September 24, 2010, from http://www.mayoclinic.com/health/chronic-myelogenous-leukemia/DS00564.

Novartis Pharmaceuticals Corporation. (2010). Commonly asked questions about the causes of Ph CML. Retrieved September 24, 2010, from http://www.mycmlcircle.com/patient/cml-causes-article.jsp.