NFKB1 and lymphoma: It plays a role in the processes of cell apoptosis, cell-cycle progression, antigen presentation, and DNA repair.273–276 The first step of protein degradation is polyubiquitination, and the proteasome binds the polyubiquitin chain and mediates deubiquitination and then degrades the target proteins to oligopeptides less than 25 amino acids (Fig. 1).277,278 Inhibition of the pro-survival NF-κB pathway is the main antitumor mechanism of proteasome inhibitors in lymphoma.279