ATRX loss induces PD-L1 and an immunosuppressive cytokine/chemokine profile in IDH1^R132H/p53_mut cells in vitro and in vivo. A. Expression quantification by qRT-PCR of 22 immune checkpoint ligands in IDH1^R132H/p53_mut+/−ATRX_loss U373 cells; inhibitory immune checkpoint molecules are labeled red and co-stimulatory ligand is labeled green. B. Immunoblots showing PD-L1 expression in IDH1^R132H/p53_mut/ATRX_loss, IDH1^R132H/p53_mut, ATRX_loss/p53_mut, and p53_mut U373 and Snb19 cells. C. Immunofluorescence showing membrane distribution of PD-L1 in IDH1^R132H/p53_mut+/−ATRX_loss U373 cells. D. Expression quantification by qRT-PCR of 21 cytokines and chemokines in IDH1^R132H/p53_mut+/−ATRX_loss U373 cells (left panel). E. Immunoblots showing IL33 level in whole cell extracts. F. and G. Immunohistochemistry and quantification of PD-L1 and IL33 in IDH1^R132H/p53_mut+/−ATRX_loss U373 tumor xenografts. H. IL-33 and CXCL3 expression in TCGA IDH1mut/non-1p19q co-deleted ATRX-mutant vs. ATRX-WT clinical samples (http://gliovis.bioinfo.cnio.es). *P < .05, **P < .01, and ***P < .001.