What is myeloma?

Myeloma is a type of cancer that develops from cells in the bone marrow called plasma cells. Bone marrow is the spongy tissue found inside the inner part of our large bones. It is from the bone marrow that our different blood cells are produced.

Myeloma can develop wherever there are plasma cells. So it can be anywhere in the bone marrow, including the pelvis, spine and ribcage. As it can be in several places, it is often called multiple myeloma.

Plasma cells are part of the immune system. They make proteins called antibodies. These are large protein molecules also called immunoglobulins. The antibodies are made when the body responds to infections. Different antibodies are made to respond to different infections. Antibodies attack and help to kill bacteria and viruses. There are 5 main types of antibody or immunoglobulin - A, G, E, M and D. In each patient, the myeloma cells produce an abnormal form of one of these types of antibody. You may hear your doctor call the antibody protein, paraprotein or a monoclonal spike.

Because the myeloma cells are making too much of the abnormal antibody, it is found in high levels in your blood and urine. The abnormal antibody does not work properly and is not able to fight infections.

In order to understand why myeloma affects you the way it does, it helps to understand how blood cells are normally produced and what they do.

Normally, blood cells are produced in the bone marrow. They are made in a controlled way, when your body needs them. All blood cells start as the same type of cell, called a stem cell. As they develop (mature), they turn into one of three types of blood cell

• White blood cells (leucocytes)
• Red blood cells (erythrocytes)
• Platelets (thrombocytes)

Plasma cells develop from a type of white blood cell called B lymphocytes. In myeloma, too many plasma cells are made. These take up much more room in the bone marrow than they would normally. This means that there is not enough space for making normal white cells, red cells and platelets.

The white cells are important for fighting infection. If you do not have enough of these, you will pick up more infections than normal and will have trouble fighting them off.

Red blood cells carry oxygen round the body. If you haven't got enough of these, you have anaemia. This can make you tired and breathless.

Platelets are vital for normal blood clotting. If you do not have enough platelets, you will have bleeding problems such as nosebleeds, very heavy periods or a fine rash of red spots caused by bleeding into the skin.

There is more about the white blood cells, red blood cells and platelets and what they each do in blood and circulation in the about your body section of CancerHelp UK.