white blood cells
Blood cancers affect the production and function of your blood cells. Most of these cancers start in your bone marrow where blood is produced. In most blood cancers, the normal production of blood cells is replaced by uncontrolled growth of an abnormal type of blood cell. These abnormal blood cells are cancerous cells, and prevent your blood from performing many of its functions, like fighting off infections or preventing serious bleeding. Leukemia is a cancer of the blood or bone marrow. It is characterized by an abnormal production of blood cells, usually white blood cells. Lymphoma is a cancer of a type of white blood cell called lymphocytes. There are many types of lymphoma.