Types of myeloma
There are different types of myeloma. The treatment you need is usually the same whichever type you have but the type can change how it affects you.
There are also some other conditions related to myeloma that affect plasma cells.
Immunoglobulins and your type of myeloma
Most people have a type of myeloma that causes the abnormal plasma cells to produce abnormal proteins. These proteins are called immunoglobulin (also called abnormal protein, paraprotein, monoclonal protein or monoclonal spike). As well as the whole immunoglobulin, often a small part called the free light chain (called Bence Jones protein in urine) is made in big amounts by the plasma cells.
Each immunoglobulin is made up of 2 long protein chains (called heavy chains) and 2 shorter protein chains (called light chains).
Immunoglobulins can be classified into one of 5 types depending on their heavy chains. These are A, G, M, D and E. Your type of myeloma is named after the abnormal immunoglobulin it is making.
Only one type of immunoglobulin (Ig) is overproduced when you have myeloma. The type of immunoglobulin this is varies from person to person. IgG is the most common. The next most common is IgA and light chain only. IgM, IgD and IgE are very rare.
Light chain myeloma sometimes called Bence Jones myeloma
About 20 out of 100 people with myeloma (20%) do not produce complete immunoglobulins. They only produce part of the immunoglobulin called the light chain.
There are 2 types of light chains - called kappa and lambda. The light chains can show up in the urine. Doctors call this the Bence Jones protein (BJP).
A blood test called a serum free light chain test can pick up small increases in the amount of free light chains in the blood. Doctors use this test to:
- measure the amount of each of the light chains in the blood
- to compare the amount of kappa light chains to the amount of lambda light chains, known as the ratio
Your doctor can use the test to diagnose and monitor your myeloma.
Non secretory myeloma
In about 3 out of every 100 people with myeloma (3%), the myeloma cells produce little or no immunoglobulin (also called paraprotein). This makes it harder to diagnose.
Doctors use bone marrow tests and scans (such as PET-CT) to diagnose and monitor non secretory myeloma.
Types of myeloma depending on gene changes
Myeloma develops because of changes in genes that become abnormal. Genes are the instruction manuals for cells ‘telling’ them how to behave. There are subtypes of myeloma based on the changes in their genes. Your genetic subtype depends on the changes there are in the genes of the myeloma cells.
Knowing the genetic subtype can help doctors know how your myeloma might progress.
Doctors are researching how particular genetic subtypes of myeloma might be treated differently in the future.
Other conditions related to myeloma
Monoclonal gammopathy of undetermined significance (MGUS)
If you have MGUS your plasma cells make too many large protein molecules known as immunoglobulins or paraproteins (also called abnormal protein, monoclonal protein or monoclonal spike). These show up in the blood.
MGUS is often found by chance, in blood tests for a routine check up, or tests for a different medical problem. This is because MGUS does not cause any symptoms, and does not generally affect your health.
MGUS is diagnosed if you have:
- a low level of abnormal paraprotein in your blood (less than 30 g/l)
- a low level of abnormal plasma cells in your bone marrow (less than 10%)
- no evidence of certain other related conditions
- no related problems with organs or tissues
Because it doesn't usually cause any symptoms or cause problems, MGUS does not usually need treatment. Some people with MGUS go on to develop myeloma, so your specialist or GP will see you regularly for check ups. About 1 out of 100 people with MGUS (1%) develop myeloma each year.
A plasmacytoma is a tumour made up of plasma cells together in a lump. They can be found in bone or soft tissue. You might have one area of plasmacytoma and this is called solitary plasmacytoma. Some people have more than one plasmacytoma and this is called multiple solitary plasmacytoma.
The areas of plasmacytoma are similar to the areas of plasma cells found in people with multiple myeloma.
More than half of people with bone plasmacytoma go on to develop myeloma later in life. Soft tissue (or extramedullary) plasmacytoma can also develop into myeloma but is less common.
Doctors usually treat plasmacytoma with radiotherapy.
This is a rare conditon. The plasma cells make an abnormal protein called amyloid. The amyloid collects in body organs, such as the kidneys or heart, and gradually causes damage.
About 10 to 15 out of every 100 people with myeloma (10 to 15%) develop amyloidosis. But it doesn't always cause problems. However, it is rare for people with amyloidosis to develop myeloma. Doctors usually treat amyloidosis with chemotherapy, and use the same drugs that you would have for myeloma.