STAT3 and glioblastoma: Further, we validated our novel marker genes CD274 and CHI3L1 along with STAT3 phosphorylation to show an enrichment in tumor-associated astrocytes of specimens of de-novo glioblastoma by immunostaining (Fig. 1e–g), as well as western blot of three patients with paired non-infiltration cortex and peritumoral region specimens and FACS analysis Supplementary Fig. 5.