[The clinical significance of M proteins]

M protein refers to a monoclonal gammaglobulin that is produced by the monoclonal proliferation of plasma cells. More than 50% of M proteinemia is classified as MGUS, but lymphoproliferative disorders such as multiple myeloma and Waldenström's macroglobulinemia may also develop from MGUS. Therefore, in patients with MGUS it is very important to observe the clinical course. MGUS develops in many disorders including chronic infection, autoimmune disease, various type of neoplasm, neurological disease and skin disease. In general, no treatment is required for MGUS and smoldering type myeloma in which the clinical course and laboratory data are stable. However, in progressive myeloma or cases of plasmacytoma chemotherapy, radiation and/or surgery are indicated. Some factors are known to predict the prognosis of multiple myeloma, and poly(A) polymerase may be a useful indicator for predicting the prognosis of multiple myeloma.