To delineate soluble T cell-derived factors that can induce TSPO upregulation in BTICs, we studied the TCGA-GBM dataset for genes co-expressed with TSPO. TSPO expression positively correlated with IFNGR1, IFNGR2, TNFRSF1A, and TNFRSF1B expression in GB (Additional File 1: Supplementary Fig. 2a). Here, TNFRSF1A is linked to glioblastoma.