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What Is CML?


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Chronic myelogenous leukemia (also called CML or chronic granulocytic leukemia) is a disease in which the bone marrow makes too many white blood cells. CML is a slowly progressing blood and bone marrow disease that usually occurs during or after middle age, and rarely occurs in children.

Normally, the bone marrow makes blood stem cells (immature cells) that develop into mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell. The lymphoid stem cell develops into a white blood cell. The myeloid stem cell develops into one of three types of mature blood cells:

  • Red blood cells that carry oxygen and other materials to all tissues of the body
  • Platelets that help prevent bleeding by causing blood clots to form
  • Granulocytes (white blood cells) that fight infection and disease.

In CML, too many blood stem cells develop into a type of white blood cell called granulocytes. These granulocytes are abnormal and do not become healthy white blood cells. They may also be called leukemic cells. The leukemic cells can build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or easy bleeding may occur.

Tests that examine the blood and bone marrow are used to detect and diagnose chronic myelogenous leukemia. The tests and procedures that may be used include physical exam and history, complete blood count, blood chemistry studies, cytogenetic analysis, and bone marrow aspiration and biopsy.

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Source: National Cancer Institute

This article was published in Coping® with Cancer magazine, March/April 2011.