Multiple myeloma is a blood cancer in which plasma cells grow out of control. Healthy plasma cells come from the bone marrow and play a key role in your immune system. With multiple myeloma, the plasma cells create a buildup of an abnormal protein in your bones and blood, which can lead to multiple myeloma symptoms like bone pain, anemia, and infections, among other problems. Your multiple myeloma prognosis depends on risk factors like age, race, and family history of the disease. It’s rarely cured, so treatments typically focus on relieving symptoms, reaching remission, and helping you live longer. Treatments include watchful waiting, targeted therapies, and stem cell transplants.