In this connection, the incorporation of M-protein (IgG), possibly by endocytosis, has been demonstrated by immunoelectron microscopy in various bone marrow cells such as erythroblasts, monocytes, reticulum cells, megakaryocytes, and stromal cells in a case of IgG-κ type multiple myeloma [17]. The gene discussed is MYOM2; the disease is plasma cell myeloma.