Causes
By Mayo Clinic staffDoctors aren't certain what starts the process that causes chronic lymphocytic leukemia. Doctors know that something happens in order to cause a genetic mutation in the DNA of blood-producing cells. This mutation causes the blood cells to produce abnormal, ineffective lymphocytes — one type of white blood cell that helps your body fight infection.
Beyond being ineffective, these abnormal lymphocytes continue to live and multiply, when normal lymphocytes would die. The abnormal lymphocytes accumulate in the blood and certain organs, where they cause complications. They may crowd healthy cells out of the bone marrow and interfere with normal blood cell production.
Doctors and researchers are working to understand the exact mechanism that causes chronic lymphocytic leukemia.
- Lichtman MA, et al. Williams Hematology. 8th ed. New York, N.Y.: The McGraw-Hill Companies; 2010. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=69. Accessed March 7, 2013.
- Abeloff MD, et al. Abeloff's Clinical Oncology. 4th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2008. http://www.mdconsult.com/das/book/body/208746819-4/0/1709/0.html. Accessed March 7, 2013.
- Chronic lymphocytic leukemia. The Leukemia & Lymphoma Society. http://www.lls.org/#/resourcecenter/freeeducationmaterials/leukemia/cll. Accessed March 7, 2013.
- Chronic lymphocytic leukemia treatment (PDQ). National Cancer Institute. http://www.cancer.gov/cancertopics/pdq/treatment/CLL/patient. Accessed March 7, 2013.
- When cancer doesn't go away. American Cancer Society. http://www.cancer.org/treatment/survivorshipduringandaftertreatment/when-cancer-doesnt-go-away. Accessed March 7, 2013.
- Cancer-related fatigue. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed March 7, 2013.
- Shanafelt TD, et al. Phase 2 trial of daily, oral polyphenon E in patients with asymptomatic, Rai stage 0 to II chronic lymphocytic leukemia. Cancer. 2013;119:363.
- Green tea. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed March 7, 2013.
- Shanafelt TD, et al. Hematologist/oncologist disease-specific expertise and survival: Lessons from chronic lymphocytic leukemia (CLL)/small lymphocytic leukemia (SLL). Cancer. 2012;118:1827.
- Shanafelt TD (expert opinion). Mayo Clinic, Rochester, Minn. April 2, 2013.


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