TNFSF13B and plasma cell myeloma: The TNFSF13B ligand (or BAFF) is a member of the TNF cytokine family that activates nuclear factor (NF)-κB, phosphatidylinositol-3 kinase (PI3K)/AKT, and mitogen-activated protein kinase (MAPK) pathways in myeloma multiple cells, and induce strong up-regulation of Mcl-1 and Bcl-2 antiapoptotic proteins [34].