What is myeloma?

Myeloma is a type of blood cancer that develops from plasma cells Open a glossary item in the bone marrow. Plasma cells are a type of blood cell that makes antibodies to fight infection. The bone marrow makes them. In myeloma, the bone marrow makes lots of abnormal (cancerous) plasma cells.

Bone marrow is the spongy tissue found inside the inner part of some of our large bones. The bone marrow produces different types of blood cells. 

Myeloma is sometimes called multiple myeloma because it affects more than one part of your body. 'Multiple myeloma' and 'myeloma' mean the same thing. In this information, we always use the term myeloma.

Diagram of bone marrow

What are plasma cells?

Plasma cells are part of the immune system. Normal plasma cells make proteins called antibodies. These antibodies are also called immunoglobulins.

The plasma cells make antibodies when the body responds to infections. They make different antibodies for different infections. Antibodies attack and help to kill bacteria and viruses and so protect us from infections.

There are 5 main types of antibody (immunoglobulin) – A, G, M, D and E. These are called IgA, IgG, IgM, IgD and IgE.

Diagram of an antibody

How does myeloma develop?

Myeloma develops when there is a change in the DNA of the plasma cells. DNA is the instructions for the cell so it knows what to do and when. The change happens to the DNA when the bone marrow is making new plasma cells. The abnormal plasma cell then divides and multiplies and produces more abnormal plasma cells. These are myeloma cells.

Myeloma cells make abnormal types of antibodies called paraproteins. The abnormal antibodies aren't able to work normally and can't help fight infections. You might hear your doctor call the antibodies different names such as:

  • abnormal proteins
  • paraproteins
  • monoclonal proteins
  • a monoclonal spike  

Paraproteins are often found in the blood and urine if you have myeloma. One part of the paraprotein is called the light chain. This is also known as the Bence Jones protein. The body gets rid of the light chain in the urine. So blood and urine tests are a way of detecting these light chains to diagnose and monitor myeloma.

This video is about myeloma. It lasts for 2 minutes and 58 seconds.

How myeloma affects your body

Myeloma doesn't form a lump or a tumour. Most of the problems it causes are because of a build up of abnormal plasma cells in the bone marrow and the paraprotein in the body.

Myeloma affects areas where you have active bone marrow. This includes your arms and legs and your shoulders as well as your spine, skull, pelvis and rib cage.  Myeloma affects several places in the body which is why it is sometimes called multiple myeloma.

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

Blood cells and myeloma

Usually bone marrow makes blood cells 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 and they are all of the same type. They crowd the bone marrow. This means that there is not enough space for making normal white cells, red cells and platelets.

Diagram showing the cell line plasma cells come from

What do your blood cells do?

The white cells are important for fighting infection. If you don't have enough white blood cells, you will pick up more infections, and infections might take longer to get better. 

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

Platelets are important for normal blood clotting. If you don't have enough platelets, you might bleed more. You might have nosebleeds, very heavy periods, or a fine rash of red spots caused by bleeding into the skin.

Types of myeloma and other related conditions

There are different types of myeloma. Your type is named after the abnormal immunoglobulin (paraprotein) made by the myeloma cells. IgG is the most common type. The next most common is IgA and light chain only. IgM, IgD and IgE are very rare. 

There are some other conditions that affect plasma cells and are related to myeloma. These include:

  • monoclonal gammopathy of undetermined significance (MGUS)
  • plasmacytoma
  • amyloidosis

How common is myeloma?

Around 6,000 people are diagnosed with myeloma in the UK each year. That is 16 people every day. 

Who gets it?

Myeloma is more common in men than women.

It is more common in older people. In the UK, on average each year around 45 out of 100 (around 45%) of new cases are in people aged 75 and over. It is very rare in people younger than 40. 

Last reviewed: 
06 Oct 2023
Next review due: 
06 Oct 2026

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