memo - Magazine of European Medical Oncology | 2021
Paraprotein-associated diseases: a complex relationship between monoclonal gammopathy of unknown significance and severe organ damage
Abstract
In this special issue we want to introduce new insights into a complex relationship between monoclonal gammopathy of unknown significance (MGUS) [1, 2], monoclonal gammopathy of renal significance (MGRS) [3], immunoglobulin light chain amyloidosis (AL) [4] and monoclonal gammopathy with clinical significance (MGCS) [5]. All of them are categorized as M-protein related diseases. MGUS is a premalignant condition with an incidence of 3% for persons who are 50 years of age, with the incidence continuously increasing with age. MGUS and smoldering multiple myeloma (SMM) are defined by a measurable paraprotein (M-protein, M-spike or M-gradient), a detectable clonal plasmacell or B-cell population in the bone marrow, and without any related organ damage. Hematologists and oncologists are trained to be aware of progression from MGUS/SMM to multiple myeloma (MM). In rare cases, the premalignant condition does not progress into malignant uncontrolled cell growth like plasma-cells in MM but the clonal M-protein can acquire a “toxic” character and causes severe tissue damage or life-threatening organ dysfunction. It is important to realize that the severity of the injury is independent of the M-protein concentration. Very low levels of M-protein can induce severe and highly dangerous organ dysfunction. In recent years, knowledge about the diverse categories of M-protein induced organ damages has been continuously growing. Intensive efforts have been made to improve awareness and clarify the complex