The International Myeloma Working Group (IMWG) has defined smoldering multiple myeloma as a disorder where the patient has a serum monoclonal (M) protein (IgG or IgA) ≥3 g/100 ml and/or clonal bone marrow plasma cells (BMPCs) of ≥10%, but no CRAB symptoms (increased calcium level, renal failure, anemia or destructive bone lesions) [4]. This evidence concerns the gene PROS1 and plasma cell myeloma.