Until 2009, it was generally accepted that monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma, and multiple myeloma were three distinctly separate diseases.

If MGUS was accidentally discovered during a patient’s routine medical testing, the patient was often advised to ignore the abnormal test results for the foreseeable future. Most clinical settings encouraged only infrequent routine monitoring, since both MGUS and smoldering myeloma conditions were considered distinct diseases with a small probability of the patient developing multiple myeloma. Often …