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Myeloma is really not just one disease. It's a disease with several subtypes.

In all cases of myeloma, abnormal plasma cells produce an unusually high number of only one the types of antibodies – or immunoglobulins, as doctors often call them.  

The specific type of immunoglobulins that are overproduced by cancerous plasma cells can vary from one person to the next, and determine the subtype of myeloma the patient has. 

Did you know?

  • When plasma cells are exposed to foreign substances (antigens), they produce different antibodies called immunoglobulins (Ig).
  • Immunoglobulines are made up of two types of proteins:
    • heavy chains (A, G, M, D and E)
    • light chains (kappa or lambda)
  • About 60% to 65% of all cases of myeloma involve the overproduction of IgG. 
  • When too much of the same immunoglobulin is produced, this is referred to as the monoclonoal protein (M-protein), monoclonal spike (M-spike), monoclonal peak (M-Peak) or paraprotein.


  Subtypes of myeloma

MGUS (Monoclonal Gammopathy of Undertermined Significance)

  • Benign condition in which the M-protein (or paraprotein) is present, but there is no underlying disease – i.e., no anemia, renal failure, excessive calcium in the blood or bone lesions.
  • Although there may be more plasma cells than normal in the bone marrow, they account for less than 10% of blood cells (the threshold for a diagnosis of myeloma).
  • Approximately 3.2% of the general population 50 years of age and older have MGUS. Of those, about 1% per year will develop active myeloma.
  • Usually monitored but not treated.
Asymptomatic and smouldering myeloma
  • Transitional state between MGUS and active myeloma.
  • M-protein is present in the blood and/or urine.
  • Plasma cells may account for up to 10% of blood cells in the bone marrow.
  • Still no symptoms or organ damage.
  • Usually monitored but not treated. Supportive care may be given.
Symptomatic or active myeloma
  • M-protein is present in the blood or urine.
  • Plasma cells account for 10% or more of blood cells in the bone marrow.
  • Symptoms or complications may include one or more of the following:
    • C = Calcium elevation in the blood
    • R = Renal insufficiency (kidney failure)
    • A = Anemia (low red blood count)
    • B = Bone disease (pain, increased risk of fractures, etc.)
  • Requires treatment.

For more information, dowload the Multiple Myeloma Patient Handbook
Designed to provide educational support to patients, caregivers, families, and friends, this handbook gives accurate, reliable, and clear information on myeloma. Topics cover its causes and effects, how it is diagnosed, and the treatment options available in Canada.
Download it now.