TNFSF11 and plasma cell myeloma: Antibodies to various myeloma cell markers, such as CD40, CD56, CD74, IL-6, TRAIL, and RANKL, combined with proteasome inhibitors, conventional chemotherapy, and/or immunomodulatory agents, may serve as maintenance targets for future research with an ultimate goal of significantly improving OS or potentially curing multiple myeloma [27, 65].