Chronic Myelogenous Leukemia Health Center

About 20,000 people in the United States are affected by chronic myelogenous leukemia, and about 4,500 people are newly diagnosed every year.

Chronic myelogenous leukemia, also known as CML, is a slowly progressing blood and bone marrow disease that usually develops during or after middle age and rarely affects children.

Normally, the bone marrow produces blood stem cells that develop into mature blood cells over time. A blood stem cell may become a myeloid stem cell which develops into either red blood cells, platelets or granulocytes (white blood cells), or it can become a lymphoid stem cell which develops into a white blood cell.

WIth CML, too many blood stem cells develop into white blood cells called granulocytes. These particular granulocytes are abnormal and do not transition into healthy functioning white blood cells that actively fight infection and illness. Instead, they may develop into leukemic cells which can build up in the blood and bone marrow so there is less space for healthy white blood cells, red blood cells and platelets.

Most individuals with CML have a gene mutation known as the Philadelphia chromosome. This chromosome, or container of DNA, involves part of the DNA from one chromosome moving to another chromosome. The result is the creation of an enzyme called tyrosine kinase which causes an excess of stem cells to develop into white blood cells. While the Philadelphia chromosome cannot be passed from parent to child, it is unknown how exactly one develops it.

Review Date: 
August 20, 2012
Last Updated:
June 2, 2014