EGR1 and glioblastoma: Tumor drivers like BCAN, APOE, or EGFR were stronger expressed in both models compared to monocultured GBM cells, as were genes associated with neuronal function, including EGR1, FOS, or MARCKS. A comparison of gene expression levels for complete KEGG pathways for all three models is displayed in Fig. S5 showing a higher similarity between hGliCS and mouse xenograft compared to monocultured GBM.