PSMB9 and neoplasm: Although RNA sequencing of ex vivo bulk tumor and sorted tumor cells showed similar expression of the MHC class I α (H2-D1 and H2-K1) and β (B2m) chains between CT2A-luc and GL261-luc2, CT2A-luc displayed lower expression of genes associated with the immunoproteasome complex (Psmb8, Psmb9) and peptide transporter/loading complex (Tap1, Tap2, Tapbp) (differential expression analysis, all FDR-adjusted p<0.05; Figure 3C; Supplementary Figure 4A).