NFKB1 and plasma cell myeloma: While blocking proteasomal degradation of IκB might have been an impetus for trialing proteasome inhibitors such as bortezomib (Velcade, PS-341) for the treatment of Multiple Myeloma (MM) [93,238,241], the anti-cancer activity of proteasome inhibitors is unlikely to be due only to their ability to block NF-κB activation [253] (Figure 5).