DKK1 and plasma cell myeloma: For examine, multiple myeloma has been well studied, and 60% of patients have osteolytic lesions.143 Menu et al. reported that EVs derived from multiple myeloma cells not only enhanced the activity of osteoclasts but also inhibited the activity of osteoblasts by reducing the expression of Runx2, Osterix and collagen-1A in osteoblasts by mediating the transfer of DKK-1.143 Moreover, other evidence indicates that multiple myeloma-derived EV-rich amphiregulin (AREG).144 and lncRUNX2-AS1.145 may be critical factors that promote osteoclast activity or inhibit osteoblast activity.