Chronic Lymphocytic Leukemia (CLL) | Learn About Cancer | American Cancer Society
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Chronic Lymphocytic Leukemia (CLL)

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Chronic lymphocytic leukemia (CLL) is a type of cancer that starts from white blood cells (called lymphocytes) in the bone marrow. CLL mainly affects older adults, and accounts for about one-third of all leukemias.

Learn About Chronic Lymphocytic Leukemia

Whether you’re worried about developing chronic lymphocytic leukemia, making decisions about treatment, or trying to stay well after treatment, we can help. Find detailed information in our Detailed Guide, or get a shorter, simpler version in If You Have Chronic Lymphocytic Leukemia.

Chronic Lymphocytic Leukemia Causes and Risk Factors

Learn about the causes of chronic lymphocytic leukemia and what you might be able to do to help lower your risk.

Chronic Lymphocytic Leukemia Treatment and Support

If you are facing chronic lymphocytic leukemia, we can help you learn about your treatment options and possible side effects, and point you to information and services to help you get through treatment and live well afterward.

Explore Research

The American Cancer Society is committed to relentlessly pursuing the answers that will save lives from leukemia. In fact, the Society has been a part of nearly every major cancer research breakthrough in recent history.

Get Involved

You can make a difference in the fight against cancer by volunteering your time, participating in an event, or donating to the cause. Find out about all the ways you can get involved today.

Stories of Hope

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Read inspiring stories of people living with leukemia.

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Online Support Communities

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Facing leukemia?  Connect with others and get support through our online communities, Cancer Survivors Network and

Chronic Lymphocytic Leukemia in the News

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Read the latest developments in chronic lymphocytic leukemia.

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