NFKB1 and cancer: Similarly, SUMO, a prominent ubiquitin-like protein, can be conjugated to the DUB CYLD at Lys40, a modification that does not impair substrate binding, but does reduce the ability of CYLD to deubiquitinate TRAF2 and TRAF6, promoting NF-κB signaling, and potentially leading to cell cycle dysregulation and cancer (189).