TNFSF13B and plasma cell myeloma: Investigators have reported that myeloma cells express transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI) and B-cell maturation antigen (BCMA), two genes coding for receptors of BAFF (also known as Blys).11 BAFF, a member of the tumor necrosis factor (TNF) family, was identified as a key factor in the normal B-cell biology.