Multiple myeloma (MM) is defined as a part of the spectrum of monoclonal gammopathy and a clonal plasma cell proliferative disorder. This disorder is characterized by an abnormal increase in monoclonal paraprotein, leading to end-organ damage.

Multiple Myeloma monoclonal gammopathy of undetermined significance (MGUS) or the detection of monoclonal antibodies in blood or urine without causing end-organ damage, has a risk of progression risk to MM in about 1% per year.