Acute myelogenous leukemia (AML) is a fast-growing cancer of the blood and bone marrow. In AML, the bone marrow makes many unformed cells called blasts. Blasts normally develop into white blood cells that fight infection. However, the blasts are abnormal in AML. They do not develop and cannot fight infections. The bone marrow may also make abnormal red blood cells and platelets. The number of abnormal cells (or leukemia cells) grows quickly. They crowd out the normal red blood cells, white blood cells and platelets the body needs.