ZUP1 and neoplasm: TNFα upregulates CSN5 expression through activation of the transcription factor NF-κB p65, which directly transactivates the promoter of the CSN5-encoding gene.100 Another DUB, USP22, also stabilizes PD-L1 in tumor cells via deubiquitination and suppresses antitumor immunity in mouse tumor models.203,204 While USP22 interacts with PD-L1 and inhibits PD-L1 ubiquitination, this DUB binds and stabilizes CSN5, suggesting that its PD-L1-regulatory function may involve coordination with CSN5.204