Overview

Leukemia is a cancer of the blood. Leukemia begins when normal blood cells change and grow uncontrollably. Acute myeloid leukemia (AML) is a cancer affecting white blood cells. AML may sometimes be called acute myelogenous leukemia, acute myelocytic leukemia, or acute nonlymphocytic leukemia. Unlike chronic leukemia, acute leukemia develops quickly and generally requires immediate treatment. AML occurs in people of all ages but is most common in adults older than 65.

AML is a disorder of the process that normally produces neutrophils, a type of white blood cell. Neutrophils fight infections caused by bacteria. The production of mature neutrophils usually is highly regulated. For example, the body rapidly makes more neutrophils during an infection and returns to a regular level of production when the infection is controlled. Mature neutrophils develop from immature white cells in a process called differentiation.

In AML, acquired mutations (damage to the genetic material or DNA) in the blood-forming cells disrupt the normal process of differentiation, resulting in the increase of large numbers of immature (undeveloped) cells called myeloblasts or blasts. Blasts cannot function like fully developed, healthy blood cells. The large number of blasts also reduces the production of healthy red blood cells and platelets. Therefore, people with AML are usually anemic (because they do not have enough red blood cells), susceptible to infection (because they do not have enough mature neutrophils), and bruise or bleed easily (because of a low level of platelets).

AML is usually found in the blood and bone marrow (the spongy, red tissue in the inner part of the large bones), but it can sometimes also invade other sites, such as the brain, skin, and gums. Occasionally, AML cells can form a solid tumor called a myeloid sarcoma or chloroma that may be located nearly anywhere in the body.