M-protein (also called myeloma protein or paraprotein) denotes an antibody or a fragment of an antibody that is produced in abnormal amounts by a pre-malignant or malignant plasma cell and is used as a marker for haematological malignant diseases such as myeloma as well as the asymptomatic disease monoclonal gammopathy of undetermined significance (MGUS). Here, MYOM2 is linked to plasma cell myeloma.