This video: Multiple myeloma is a cancer that forms in a type of white blood cell called a plasma cell. Plasma cells help you fight infections by making antibodies that recognize and attack germs.
Multiple myeloma causes cancer cells to accumulate in the bone marrow, where they crowd out healthy blood cells. Rather than produce helpful antibodies, the cancer cells produce abnormal proteins that can cause kidney problems.
Treatment for multiple myeloma isn't always necessary. If you're not experiencing signs and symptoms, you may not require treatment. If signs and symptoms develop, a number of treatments can help control your multiple myeloma.