What Is Acute Myeloid Leukemia?

This content has been reviewed and approved by

Hagop M. Kantarjian, MD
Chairman & Professor, Leukemia Department
MD Anderson Cancer Center
University of Texas

Acute myeloid leukemia (AML) is a cancer of the blood. AML occurs because too many granulocytes (a type of white blood cell) are produced in bone marrow. Bone marrow is the soft matter inside bones where blood cells are made.

An estimated 13,290 cases of AML will be diagnosed in the United States in 2008, according to the American Cancer Society. AML is the second most commonly diagnosed form of leukemia. It will account for about 30 percent of new U.S. cases of the disease in 2008, according to the ACS.

AML affects mainly older adults, and is more common in men than among women. The average age of a patient with AML is 67, the ACS says. 

Normally, bone marrow cells mature into several different types of blood cells. AML affects the young blood cells (called blasts) that develop into granulocytes. The main function of these white blood cells is to destroy bacteria.

In AML, the blasts fail to mature. These immature cells are called myelocytes. They also become too numerous. Large numbers of these defective cells accumulate in bone marrow and blood. The word “acute” means that the increase in cells caused by AML can occur over a short period of days to weeks.

Abnormal chromosomes (extra chromosomes [DNA] and structural changes in the chromosomes) are found in most AML patients. Chromosomes carry a person’s genetic traits.