Multiple myeloma is a type of cancer that begins in the body’s blood cells. In 2008, an estimated 19,920 new cases of multiple myeloma will be diagnosed in the United States, according to the American Cancer Society. Most individuals are over 40 years old when diagnosed. Multiple myeloma affects men slightly more often than women.
Multiple myeloma occurs when the bone marrow, the soft spongy material inside bones, begins producing abnormal plasma cells. Healthy plasma cells are blood cells that play an important role in your body’s immune system, which defends it against infection and disease. They produce proteins that target specific germs, bacteria, and other foreign substances that could harm your body or make you sick. People with multiple myeloma have large numbers of abnormal plasma cells in the bone marrow. These cells also produce abnormal proteins.
At first, multiple myeloma may not cause any symptoms. As more and more abnormal plasma cells crowd the bone marrow and spread through the body, symptoms begin to develop. These can range from bone damage and pain to weakness, fatigue, and infection.
Other names for multiple myeloma are plasma cell myeloma, bone marrow cancer, myelomatosis, and Kahler's disease. Although multiple myeloma affects bones and develops within bones, it is not bone cancer because it develops from the blood cells.
Although the exact cause of multiple myeloma is not known, certain risk factors for the disease have been identified. These include increased age, being African-American, and having family members who were diagnosed with multiple myeloma. Frequent exposure to petroleum, pesticides, or other chemicals, or to high amounts of radiation, are other possible risk factors.