Acute myeloid leukemia (AML) is a blood cancer that starts with one or more changes to the DNA of a single stem cell in the bone marrow. Stem cells form red blood cells, white blood cells and platelets.
AML is a rapidly progressing leukemia that originates in the myeloid cells. These cells are made in the bone marrow, the soft spongy inner part of the bone. AML can quickly spread from the bone marrow into the blood allowing it to affect other parts of the body.
Normally, the bone marrow makes blood stem cells that become mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell.
A myeloid stem cell becomes one of three types of mature blood cells:
- Erythrocytes: red blood cells that carry oxygen and other substances to all tissues of the body
- Granulocytes (Basophils, Eosinophils, Neutrophils, Mast cells): white blood cells that fight infection and disease
- Platelets: cells that form blood clots to stop bleeding
In AML, the myeloid stem cells usually become a type of immature white blood cell called myeloblasts. You will also hear of these cells being referred to as "blasts" or "leukemia cells". The myeloblasts in AML are abnormal and do not go on to become healthy white blood cells. Sometimes in AML, too many stem cells also become abnormal red blood cells or platelets. When leukemia cells build up in the bone marrow and bloodstream, there is less room for healthy white blood cells, red blood cells, and platelets.
These changes in the blood cells can lead to complications such as:
- Anemia due to fewer red blood cells which leads to a decrease of oxygen in the blood
- Bleeding due to a lack of platelets which clot your blood
- An increased risk of infection due to the decrease in white blood cells which fight off infection
These complications often cause symptoms such as weakness, fatigue and bone pain.
Without treatment, AML can spread quickly to other parts of the body such as the:
- Lymph nodes
- Brain and Spinal Cord
There are many different names for AML, but they all refer to the same disease. AML is commonly referred to as Acute myelogenous leukemia or acute myeloid leukemia. The word “acute” refers to a disease of rapid progression. AML is sometimes also called acute granulocytic leukemia or acute nonlymphocytic leukemia.
While we don’t know exactly what causes AML, we do know that certain people are more prone to the development of this cancer due to certain modifiable and non-modifiable risk factors.
AML risk factors include:
- Age: although AML can occur at all ages, more than 50% of AML patients are diagnosed when they are 65 or older
- Gender: although we don’t yet understand why, AML is more common in men than it is in women
- Smoking: exposure to tobacco smoke is linked to a higher risk of AML
- Previous cancer treatment: previous exposure to chemotherapy or radiation therapy is correlated with a higher risk of AML development
- Exposure to radiation: long-term exposure to radiation is known to increase the risk of AML
- Dangerous chemical exposure: exposure to a chemical called benzene found in petroleum and cigarette smoke is known to increase the risk of AML
- Other blood disorders: Blood disorders, specifically bone marrow disorders, can cause AML to develop over time. These are called myeloproliferative disorders. Myelo- meaning bone marrow and proliferative means too much or excessive.
- Genetic Disorders: More research is surfacing about the familial involvement in genetic disorders resulting in AML. Some of the known inherited disorders associated with AML include:
- Down syndrome
- Ataxia telangiectasia
- Li-Fraumeni syndrome
- Klinefelter syndrome
- Fanconi anemia
- Wiskott-Aldrich syndrome
- Bloom syndrome
- Familial Platelet Disorder Syndrome