If the M-protein (IgG or IgA) is ≥30 g/L (or urinary M-protein ≥500 mg per 24 h) and/or the clonal bone marrow plasma cell infiltration reaches 10–60% in the absence of myeloma defining events the definition of smoldering multiple myeloma (SMM) is fulfilled [2] (Figure 1). Here, CD79A is linked to plasma cell myeloma.