What is Multiple Myeloma?

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Multiple myeloma is a kind of blood cancer that develops in the bone marrow where plasma cells (a type of white blood cell) are found. The normal function of plasma cells is to synthesise proteins known as antibodies which help fight off infectious diseases.  In multiple myeloma, however, plasma cells undergo abnormal growth and form tumours in different areas of the bones.


Antibodies, also known as immunoglobulins, are proteins circulating in the bloodstream that the immune system activates to fight against antigens (bacteria, viruses or allergens). There are different types of antibody for each antigen, i.e., the antibody for one disease is different from that for another disease.

In the case of autoimmune diseases the body creates antibodies that attack its own tissues because it identifies otherwise healthy organs as foreign bodies.

There are five types of antibody:

  1. Immunoglobulin A (IgA). This is one of the main antibodies. Found in high concentrations in the mucous membranes lining the respiratory and gastrointestinal tracts, in saliva and in tears.
  2. Immunoglobulin G (IgG). This is the most abundant antibody found in bodily fluids; it protects against viral infections and bacteria.
  3. Immunoglobulin M (IgM). Mainly found in the blood and lymph fluid. This is the first antibody produced by the body in order to fight off an infection.
  4. Immunoglobulin E (IgE). Immunoglobulin E is associated with allergic reactions or parasitic infections and is found in the lungs, skin and mucous membranes.
  5. Immunoglobulin D (IgD). Small amounts are present in the blood, but we do not know much about its biological function.

Types of multiple myeloma

The different subtypes of myeloma are classified according to the type of immunoglobulin or protein produced by the myeloma cells.

Different immunoglobulins normally have different functions in the body. Each immunoglobulin has two heavy and two light chains. There are five different types of heavy chain and two types of light chain. The type of multiple myeloma is determined through a technique called immunofixation which analyses blood and urine samples to identify both the heavy (IgG, IgA, etc.) and light chains (kappa or lambda).

Approximately 65% of patients present IgG myeloma with either kappa or lambda light chains, while the second most common type is IgA with either of the light chains. IgD, IgE and IgM myelomas are fairly rare.

How many people does multiple myeloma affect?

Multiple myeloma corresponds to 10% of all bone marrow cancers. Myeloma is the second most common blood cancer and affects thousands of people across the world. It most typically develops in people aged 65–70 years. Multiple myeloma has a slightly higher incidence in men than in women. People of African descent present the highest risk of developing myeloma, while Asians have the lowest risk.



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Substantiated information by:

Carlos Fernández de Larrea Rodríguez
Gloria Garcia Barriga

Published: 20 February 2018
Updated: 20 February 2018


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