AML, one of the most common leukemias in adults, is diagnosed in about 13,400 people in the United States each year. The incidence of AML rises in those over 50 and the average age at diagnosis is 67. The disease affects more men than women.
How AML Develops
The bone marrow contains immature cells called hematopoietic stem cells, which can mature into a range of different kinds of blood cells, including white blood cells. Normal, healthy white blood cells, which fight infection, have a very short life span -- sometimes only a few hours long -- and are continuously replenished in the bone marrow. They proceed through their life cycles in an orderly way, and when they die they are replaced by new cells.
AML arises in cells that should go on to become specialized white blood cells called granulocytes and monocytes. When their DNA or genetic material becomes damaged or mutated, these poorly functioning cells begin reproducing and cannot mature beyond an early stage in their life cycle. Over time these immature cells -- called blasts -- take over the bone marrow and displace the normal red and white blood cells and platelets that are produced there. As the numbers of normal cells decline, patients may develop anemia, a condition characterized by a lack of oxygen-carrying red blood cells; infections caused by low counts of disease-fighting white blood cells; and bruising and bleeding, resulting from low levels of platelets, which are the blood component that plays a crucial role in blood clotting and wound healing. Leukemic cells may also invade the liver, spleen, lymph nodes, skin, and other organs.
