Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. It is a type of cancer that begins in cells that become certain white blood cells (called lymphocytes) in the bone marrow. Cancer (leukemia) cells start in the bone marrow but then travel to the blood.
Cancer begins when cells begin to grow out of control. Cells in almost any part of the body can become cancerous and spread to other parts of the body.
In CLL, leukemia cells often form slowly. Many people have no symptoms for at least a few years. But over time, the cells grow and spread to other parts of the body, including the lymph nodes, liver and spleen.
Different types of CLLDoctors agree that there seem to be 2 different types of CLL:
These 2 types of leukemia cells look alike, but lab tests can tell the difference between them.