Multiple myeloma, also known as plasma cell myeloma, is a cancer of plasma cells, a type of white blood cell normally responsible for producing antibodies. Often, no symptoms are noticed initially. When advanced, bone pain, bleeding, frequent infections, and anemia may occur. Complications may include amyloidosis.The cause is unknown. Risk factors include obesity, radiation exposure, family history, and certain chemicals. The underlying mechanism involves abnormal plasma cells producing abnormal antibodies which can cause kidney problems and overly thick blood. The plasma cells can also form a mass in the bone marrow or soft tissue. When only one mass is present, it is known as a plasmacytoma, while more than one is known as multiple myeloma. Multiple myeloma is diagnosed based on blood or urine tests finding abnormal antibodies, bone marrow biopsy finding cancerous plasma cells, and medical imaging finding bone lesions. Another common finding is high blood calcium levels.Multiple myeloma is considered treatable, but generally incurable. Remissions may be brought about with steroids, chemotherapy, targeted therapy, and stem cell transplant. Bisphosphonates and radiation therapy are sometimes used to reduce pain from bone lesions.Globally, multiple myeloma affected 488,000 people and resulted in 101,100 deaths in 2015. In the United States, it develops in 6.5 per 100,000 people per year and 0.7% of people are affected at some point in their lives. It usually occurs around the age of 61 and is more common in men than women. It is uncommon before the age of 40. Without treatment, typical survival is seven months. With current treatments, survival is usually 4–5 years. This gives a five-year survival rate around 49%. The word myeloma is from the Greek myelo- meaning "marrow" and -oma meaning "tumor".