Myeloma

Myeloma is a type of blood cancer. It develops from white blood cells in the bone marrow called plasma cells. As bone marrow is found throughout the body, myeloma can affect multiple areas at the same time, and the disease is often called multiple myeloma.

Learn more about:

• The blood
• What is myeloma?
• How does myeloma start?
• How is it different from leukaemia?
• What causes myeloma?
• Who gets myeloma?

The blood

Blood is pumped around your body to provide oxygen and nutrients to your tissues, and to remove waste products. It is made up of red blood cells, white blood cells and platelets, and each has a set function.

All three types of blood cells live for a limited time and need to be continually replaced. Most are made in the bone marrow, which is the spongy part in the centre of the bones.

The bone marrow contains stem cells. These are unspecialised blood cells that develop into mature red or white blood cells or platelets. Once mature, the blood cells are usually released into the bloodstream to carry out their set functions.

What is myeloma?

Myeloma begins when abnormal plasma cells, known as myeloma cells, start multiplying. Normal plasma cells make different types of antibodies to help the body fight infections. Abnormal plasma cells make an antibody known as paraprotein, M-protein or monoclonal protein. Paraprotein is found in the blood of most people who have myeloma.

Because the myeloma cells crowd out the bone marrow, there is less space for normal blood cells to develop and keep you healthy. As a result, a lack of:

• normal plasma cells and other white blood cells can make a person more likely to get infections
• red blood cells (anaemia) can cause fatigue
• platelets can cause bleeding and bruising.

How does myeloma start?

Bone marrow produces three main types of blood cells: red cells, white cells and platelets.

Plasma cells are a special type of white blood cell. Myeloma starts when plasma cells become abnormal and multiply, crowding the bone marrow. They usually also release an antibody (paraprotein) into the blood.

How is it different from leukaemia?

Myeloma and leukaemia are both types of blood cancer, but they affect the body in different ways. Leukaemia is the name given to cancers of white blood cells, which are usually easily detected on a blood test. Myeloma is a cancer of the plasma cells, which are found only in the bone marrow and not usually found in the blood.

What causes myeloma?

The causes of myeloma are unknown. We know that plasma cells become cancerous when there are certain changes in their DNA. DNA is found in all cells. It carries instructions that control how cells work, however, we do not know what causes DNA to change.

While exposure to certain chemicals (e.g. dioxins used in industry), high levels of radiation (e.g. from working in a nuclear power plant) and viruses (such as HIV) have been linked to an increased risk of myeloma, no known cause can be found in the majority of people with myeloma.

People with monoclonal gammopathy of undetermined significance (MGUS) are more likely to develop myeloma.

Myeloma is not considered to be hereditary (inherited) and it is rare for more than one person in a family to be affected by this disease, although this does happen occasionally.

Who gets myeloma?

Myeloma is not a common disease. About 1900 people in Australia are diagnosed with the disease each year. It accounts for 13% of blood cancers and around 1% of all cancers generally.

The disease is more often found in people over 60, which is partly explained by the ageing population. It is rare in people under 40 years of age. Myeloma is slightly more common in males than in females.