Multiple myeloma
Multiple myeloma is cancer of the plasma cells in bone marrow. Bone marrow is the soft tissue inside bones. The bone marrow makes blood cells. When a person has multiple myeloma, too many blood plasma cells are made. Limited space inside the bone marrow means that fewer normal blood cells are made. This prevents normal levels of antibodies from being made, so you are less able to fight infections. Multiple myeloma spreads from the bone marrow into the bone, causing the bone to become thin, weak and more likely to break. The breakdown of the bone can cause an increase in the level of calcium in the blood. It can also affect the kidneys so that they cannot filter and clean the blood properly. Multiple myeloma is rarely seen in people under 40 years of age. There is no cure, but the condition can usually be managed successfully.