"Multiple myeloma is a cancer of the body's plasma cells. Healthy plasma cells are found in bone marrow and are key to a functioning immune system. Plasma cells work by making antibodies that protect the body from bacteria, viruses and fungi. But when plasma cells are cancerous, they make many cells just like themselves and cause damage to the body. The result is a weakening of the immune system as well as a slow destruction of the skeleton. The rogue plasma cells are like trillions of Pac-men chomping on the body's bones."