MGUS (monoclonal gammopathy of unknown significance) is a non-cancerous condition where the body makes an abnormal protein, called a paraprotein.
MGUS is not a cancer, but people who have it are at slightly higher risk of developing:
- myeloma (a cancer of blood cells called plasma cells)
- lymphoma (a cancer of blood cells called lymphocytes).
MGUS affects plasma cells, a type of white blood cell. Plasma cells make proteins called antibodies to help fight infections. With MGUS, some plasma cells make an abnormal type of antibody called a paraprotein (or M-protein). This paraprotein doesn't do anything useful, and for most people it does not cause any problems.