Multiple myeloma is a blood cancer, specifically a cancer of the plasma cells. Plasma cells are a type of immune cell that make antibodies to fight disease and infection. Multiple myeloma causes genetic changes to your immune cells that transform them from healthy cells into malignant (cancerous) myeloma cells. These cancerous cells typically bind to a person’s bone marrow and can cause bone pain. Multiple myeloma is a progressive disease, meaning it worsens over time. Other common symptoms of multiple myeloma include: fatigue, bone fracture, susceptibility to infection, and kidney failure.