Acute myelogenous leukemia

Acute myelogenous leukemia, also called AML, is a cancer of the blood and bone marrow. Bone marrow is the soft matter inside bones where blood cells are made.

The word "acute" in acute myelogenous leukemia means the disease tends to get worse quickly. It's called myelogenous (my-uh-LOHJ-uh-nus) leukemia because it affects cells called the myeloid cells. These typically develop into mature blood cells, including red blood cells, white blood cells and platelets.

AML is the most common type of acute leukemia in adults. The other type is acute lymphoblastic leukemia, also called ALL. Although AML can be diagnosed at any age, it is less common before age 45. AML also is called acute myeloid leukemia, acute myeloblastic leukemia, acute granulocytic leukemia and acute nonlymphocytic leukemia.

Unlike other cancers, there are no numbered stages of acute myelogenous leukemia.

Symptoms of acute myelogenous leukemia may include:

• Fever.
• Pain. Common places for pain include the bones, back and stomach.
• Feeling very tired.
• Paleness or change in skin color.
• Frequent infections.
• Easy bruising.
• Bleeding with no clear cause, such as in the nose or gums.
• Shortness of breath.

It's often not clear what causes acute myelogenous leukemia.

Healthcare professionals know that it starts when something causes changes to the DNA inside cells in the bone marrow. The bone marrow is the spongy material inside bones. It's where blood cells are made.

The changes that lead to acute myelogenous leukemia are thought to happen in cells called myeloid cells. Myeloid cells are bone marrow cells that can turn into the blood cells that circulate through the body. Healthy myeloid cells can become:

• Red blood cells, which carry oxygen to the body.
• Platelets, which help stop bleeding.
• White blood cells, which help fight infections.

Every cell in the body contains DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time. But when the DNA changes happen in the myeloid cells, the changes give different instructions. The myeloid cells start to make a lot of extra cells, and they don't stop.

The DNA changes cause the myeloid cells to make a lot of immature white blood cells, called myeloblasts. The myeloblasts don't work right. They can build up in the bone marrow. They can crowd out healthy blood cells. Without enough healthy blood cells, there might be low oxygen levels in the blood, easy bruising and bleeding, and frequent infections.

Factors that may increase the risk of acute myelogenous leukemia, also called AML, include:

• Older age. Acute myelogenous leukemia is most common in adults age 65 and older.
• Prior cancer treatment. People who've had certain types of chemotherapy and radiation therapy may have a greater risk of AML.
• Radiation exposure. People exposed to very high levels of radiation, such as a nuclear reactor accident, have an increased risk of developing AML.
• Dangerous chemical exposure. Certain chemicals, such as benzene, are linked to a greater risk of AML.
• Smoking cigarettes. AML is linked to cigarette smoke, which contains benzene and other known cancer-causing chemicals.
• Other blood disorders. People who've had another blood disorder, such as myelodysplasia, myelofibrosis, polycythemia vera or thrombocythemia, are at greater risk of AML.
• Genetic disorders. Certain genetic disorders, such as Down syndrome, are associated with an increased risk of AML.
• Family history. People with a close blood relative, such as a sibling, parent or grandparent with a blood or bone marrow disorder are at higher risk for AML.

Many people with AML have no known risk factors, and many people who have risk factors never develop the cancer.