PSMB9 and liver cancer: Additional IRF1 depletion restored PSMB9 and MHC-I levels, suggesting IGF2BP1 suppresses MHC-I presentation via IRF1. Surprisingly, IGF2BP1 knockdown reduced PD-L1 expression independently of IRF1 (Supplementary Fig. S4e), consistent with findings in bladder and liver cancers.23,41