Cancer starts when cells in a part of the body begins to grow out of control and can spread to other areas of the body. There are many kinds of cancer. Cells in nearly any part of the body can become cancer. To learn more about how cancers start and spread, see What Is Cancer?
Leukemias are cancers that start in cells that would normally develop into different types of blood cells. Here we will talk about acute myeloid leukemia (AML).
Acute myeloid leukemia (AML) has many other names, including acute myelocytic leukemia, acute myelogenous leukemia, acute granulocytic leukemia, and acute non-lymphocytic leukemia.
“Acute” means that this leukemia can progress quickly if not treated, and would probably be fatal in a few months. “Myeloid” refers to the type of cell this leukemia starts from.
Most cases of AML develop from cells that would turn into white blood cells (other than lymphocytes), but some cases of AML develop in other types of blood-forming cells. The different types of AML are listed in “ How is acute myeloid leukemia classified?”
AML starts in the bone marrow (the soft inner part of certain bones, where new blood cells are made), but in most cases it quickly moves into the blood. It can sometimes spread to other parts of the body including the lymph nodes, liver, spleen, central nervous system (brain and spinal cord), and testicles.
Other types of cancer can start in these organs and then spread to the bone marrow. But these cancers that start elsewhere and then spread to the bone marrow are not leukemias.
Normal bone marrow, blood, and lymphoid tissue
To understand the different types of leukemia, it helps to know about the blood and lymph systems.