The type of myeloma you have tells you the type of cell that the cancer started in. Knowing this helps your doctor decide which treatment you need.
Types of immunoglobulin
There is one main type of myeloma. The cancerous plasma cells make different antibodies in different people. The antibodies are called immunoglobulins.
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.
In each case of myeloma, only one type of immunoglobulin (Ig) is overproduced. This varies from person to person. In myeloma, IgG is the most common. IgM, IgD and IgE are very rare. All these types of myeloma are treated in the same way.
Light chain 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 test called a serum free light chain test can pick up small amounts of free light chains in the blood. Doctors measure the ratio of kappa light chains to lambda light chains. If myeloma cells make either kappa or lambda light chains, the level of that light chain is increased and the ratio becomes abnormal.
You might have blood and urine tests to diagnose and monitor this type of 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.
The serum free light chain test might pick up very low levels of paraprotein, and so can be helpful in diagnosing this type of myeloma. However, for most people, doctors use bone marrow tests to diagnose and monitor non secretory myeloma.
Other conditions related to myeloma
Monoclonal gamopathy of undetermined significance (MGUS)
Your plasma cells make too many large protein molecules known as immunoglobulins or paraproteins. 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 seem to do any harm 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 that are all one type. 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 really a collection of conditions. An abnormal protein called amyloid is made by plasma cells. 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. However, it is rare for people with amyloidosis to develop myeloma. Doctors usually treat amyloidosis with chemotherapy, and use the same drugs that are used for myeloma.