What is myeloma?

Myeloma is a type of cancer that develops from plasma cells. Plasma cells are a type of white blood cell made in the bone marrow. To understand myeloma, it can help to know a little bit about the bone marrow and plasma cells.

Bone marrow

Bone marrow is a spongy material inside our bones. It is part of the body’s immune system, which helps to protect us from infection and disease.

Bone marrow produces all the blood cells needed by the body. All blood cells in the bone marrow begin as stem cells. These stem cells then develop into three different types of blood cell:

  • red blood cells, which carry oxygen to all the cells in the body
  • platelets, which help the blood to clot and control bleeding
  • white blood cells, which fight infection.

Bone marrow producing stem cells
Bone marrow producing stem cells

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Plasma cells

Plasma cells are a type of white blood cell which fight infection. They make immunoglobulins (see below), which are also known as antibodies. These travel in the blood and help to fight any viruses or bacteria in the body. If you have an infection, your bone marrow produces more plasma cells and immunoglobulins to fight whatever is causing the infection.


Immunoglobulins are made up of two matching and shorter light chains, and two matching and longer heavy chains.

There are two types of light chain. They are called kappa and lambda. There are five types of heavy chain. They are called A, D, E, G and M.

An immunoglobin
An immunoglobin

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Each immunoglobulin is named after the type of heavy chain they have. They are called IgA, IgD, IgE, IgG and IgM. The ‘Ig’ means immunoglobulin.

Plasma cells in myeloma

Normally, plasma cells are made in a controlled way. But in people with myeloma, the process is out of control and large numbers of abnormal plasma cells (myeloma cells) are made.

The myeloma cells fill up the bone marrow and can damage the bone. This can cause bone thinning, pain and sometimes fractures. Myeloma cells can spread from the bone marrow to bones in different parts of the body. This is why myeloma is sometimes called multiple myeloma.

If the bone marrow is full of myeloma cells, it can be harder for it to make enough normal white blood cells, red blood cells and platelets.

Myeloma cells make an abnormal immunoglobulin, which cannot fight infection. This could be any one of the five types of immunoglobulin (IgA, IgD, IgE, IgG or IgM). The abnormal immunoglobulin is called a paraprotein, or M protein.

If you have myeloma, you may make less normal immunoglobulins than usual. This means it can be harder for your body to fight infections.

Back to Understanding myeloma

Types of myeloma

There are different types of myeloma. There are also other conditions that affect plasma cells which are related to myeloma.

Symptoms of myeloma

Myeloma may not cause any symptoms in the beginning, but they can develop over time.