Multiple myeloma is a type of cancer that occurs when plasma cells located in your bone marrow become malignant, or multiply out of control. When this happens, the plasma cells create a tumor which grow in several places, including the soft tissue of the bone marrow. When these tumors appear in several sites, the condition is called multiple myeloma. It usually affects people over age 50.
Experts estimate that 14,400 new cases of multiple myeloma will occur in 2001: 7,500 cases in men and 6,900 cases in women. Approximately 11,200 people in the United States are estimated to die of this disease in 2001.
The most significant risk factor for multiple myeloma is age. The average age of diagnosis is 70, and only 2 percent of cases occur in people younger than 40. In American patients, the disease is found twice as much among African Americans as Caucasian Americans. The reason for this is unknown.
The cause of multiple myeloma is generally unknown. However, some cancers can be caused by defects in the DNA. Genes that promote cell division are called oncogenes. Some studies have shown that defects in some oncogenes may develop early in people with multiple myeloma.
Plasma cells, or white blood cells, fight infection by producing antibodies. Bone marrow, a fatty tissue, is located inside your bones. In people with multiple myeloma, their bones are weakened, their bone marrow does not produce proper parts of the blood, and the small number of plasma cells that remain are abnormal and unable to fight infection.
