Leukemia, a type of cancer found in your blood and bone marrow, is caused by the rapid production of abnormal white blood cells. The two main types of leukemia are lymphocytic leukemia, which involves an increase of white blood cells called lymphocytes; and myelogenous leukemia (also known as myeloid or myelocytic leukemia), which involves an increase in white blood cells called granulocytes. The high number of abnormal white blood cells are not able to fight infection, and they impair the ability of the bone marrow to produce red blood cells and platelets. Leukemia can be acute or chronic. Acute forms of leukemia progress rapidly, while chronic forms of leukemia progress slowly.
While all the causes of leukemia are not fully understood, research has found many associations including chronic exposure to benzene at work and exposure to large doses of radiation. Benzene in cigarettes has been associated with an increased risk of leukemia of myeloid cells.
Lymphoma is a type of blood cancer that affects the lymphatic system, which removes excess fluids from your body and produces immune cells. Lymphocytes are a type of white blood cell that fight infection. Abnormal lymphocytes become lymphoma cells, which multiply and collect in your lymph nodes and other tissues. Over time, these cancerous cells impair your immune system. The two main types of lymphoma are Hodgkin lymphoma and non-Hodgkin lymphoma. Hodgkin lymphoma spreads in an orderly manner from one group of lymph nodes to another. Non-Hodgkin lymphoma spreads through the lymphatic system in a non-orderly manner. The causes of lymphoma are unknown.
Myeloma is a type of blood cancer that targets plasma cells. Plasma cells are white blood cells that produce disease- and infection-fighting antibodies in your body. In myeloma, the cells overgrow, forming a mass or tumor that is located in the bone marrow. Bone marrow is the spongy tissue found in the center of the bone, where red cells, white blood cells, and platelets are made. Myeloma cells prevent the normal production of antibodies, leaving your body’s immune system weakened and susceptible to infection.
Age is the most significant risk factor for developing myeloma. People under age 45 rarely develop the disease. Those aged 67 years or older are at greatest risk of developing myeloma. Men are more likely than women to develop myeloma, and myeloma is about twice as common among African Americans as among Caucasians.