What Is Multiple Myeloma

What Is Multiple Myeloma?
Cancer starts when cells begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas. To learn more about how cancers start and spread, see What Is Cancer?

Multiple myeloma is a cancer of plasma cells. Normal plasma cells are found in the bone marrow and are an important part of the immune system. The immune system is made up of several types of cells that work together to fight infections and other diseases. Lymphocytes (lymph cells) are one of the main types of white blood cells in the immune system and include T cells and B cells. Lymphocytes are in many areas of the body, such as lymph nodes, the bone marrow, the intestines, and the bloodstream.

When B cells respond to an infection, they mature and change into plasma cells. Plasma cells make the antibodies (also called immunoglobulins) that help the body attack and kill germs. Plasma cells, are found mainly in the bone marrow. Bone marrow is the soft tissue inside bones. In addition to plasma cells, normal bone marrow is also the home for other blood cells such as red cells, white cells, and platelets.

In general, when plasma cells become cancerous and grow out of control, this is called multiple myeloma. The plasma cells make an abnormal protein (antibody) known by several different names, including monoclonal immunoglobulin, monoclonal protein (M-protein), M-spike, or paraprotein.

There are, however, other plasma cell disorders that also have abnormal plasma cells but do not meet the criteria to be called active multiple myeloma. These other plasma cell disorders include:

Monoclonal gammopathy of uncertain significance (MGUS)
Smoldering multiple myeloma (SMM)
Solitary plasmacytoma
Light chain amyloidosis.
Multiple myeloma features
Low blood counts
In multiple myeloma, the overgrowth of plasma cells in the bone marrow can crowd out normal blood-forming cells, leading to low blood counts.

This can cause anemia (a shortage of red blood cells). People with anemia become weak and fatigued.
Multiple myeloma can also cause the level of platelets in the blood to become low (called thrombocytopenia). This can lead to increased bleeding and bruising.
Another condition that can develop is leukopenia (a shortage of normal white blood cells). This can lead to problems fighting infections.
Bone and calcium problems
Myeloma cells also interfere with cells that help keep bones strong. Bones are constantly being remade to keep them strong. Two kinds of bone cells work together to keep bones healthy and strong:

Osteoclasts break down old bone
Osteoblasts lay down new bone
Myeloma cells make a substance that tells the osteoclasts to speed up dissolving the bone. So old bone is broken down without new bone to replace it, making the bones weak and easy to break. Fractured bones are a major problem in people with myeloma. This increase in bone break-down can also raise calcium levels in the blood. Problems caused by high cal