MCL cells that are resistant to BCR signaling inhibition tend to have somatic mutations in inhibitors of the non-canonical NF-κB pathway, such as cIAP1, cIAP2, and TRAF2/3; these mutations cause resistant cell lines (Z-138, Maver-1) to depend on the deregulated non-canonical NF-κB pathway for survival and proliferation (Fig. 2). The gene discussed is TRAF2; the disease is mantle cell lymphoma.