10/31/2025
What is leukemia?
Leukemia is a term for cancers of the blood cells. Leukemia starts in blood-forming tissues such as the bone marrow. Your bone marrow makes the cells which will develop into white blood cells, red blood cells, and platelets. Each type of cell has a different job:
White blood cells help your body fight infection
Red blood cells deliver oxygen from your lungs to your tissues and organs
Platelets help form clots to stop bleeding
When you have leukemia, your bone marrow makes large numbers of abnormal cells. This problem most often happens with white blood cells. These abnormal cells build up in your bone marrow and blood. They crowd out the healthy blood cells and make it hard for your cells and blood to do their work.
What is chronic lymphocytic leukemia (CLL)?
Chronic lymphocytic leukemia (CLL) is a type of chronic leukemia. "Chronic" means that the leukemia usually gets worse slowly. In CLL, the bone marrow makes abnormal lymphocytes (a type of white blood cell). When the abnormal cells crowd out the healthy cells, it can lead to infection, anemia, and easy bleeding. The abnormal cells can also spread outside the blood to other parts of the body. CLL is one of the most common types of leukemia in adults. It often occurs during or after middle age. It is rare in children.
Chronic Lymphocytic Leukemia or CLL is cancer of the white blood cells, where abnormal cells are made. This makes it hard for the blood to do its work.