Multiple myeloma, also known as myeloma bone disease, is cancer that affects the white blood cells called plasma cells. It represents about 1 percent of all cancers in the United States, and about four to five out of every 100,000 people are diagnosed with it each year.
Plasma cells, and other white blood cells, are part of the immune system. Plasma cells produce antibodies--immune system proteins that assist the body in ridding itself of harmful substances. Each plasma cell responds to one specific substance by producing one kind of antibody. The body has many types of plasma cells, and, therefore, can respond to many types of substances.
When cancer occurs, the body overproduces plasma cells, which are abnormal and alike. These abnormal plasma cells are called myeloma cells.
Myeloma cells collect in the bone marrow and the outer layer of the bone. Because the cells begin in the blood plasma, myeloma is not a bone cancer, but is cancer that affects bones.
Myeloma cells and antibodies may cause the following symptoms:
- Bone pain
- Fractures in bones
- Weight loss
- Repeated infections
- Problems with urination
- Weakness or numbness in legs
- Back pain
- Rib pain
Because the symptoms of myeloma bone disease may resemble other bone disorders or medical problems, always consult your physician for a diagnosis.