Fig. 1

Glioblastoma grown after irradiation exhibits increased stem cell markers and microenvironmental changes. a Experimental scheme for the mouse model of GBM tumors treated with or without irradiation. For the irradiation of GBM mouse model, whole mouse brains were treated 5 times with 2 Gy ionizing radiation (2 Gy × 5) daily from day 21 to 25 following orthotopic injection (n = 4). b Hematoxylin–eosin (HE) stained images showing U87MG and LN229 grown tumors after fractionated irradiation. Average survival time is indicated. Scale bar represents 500μm. c Representative images showing the primary and grown tumors stained with several stem cell markers (OCT4, Nestin, and CD133). Scale bar represents 50 μm. d Representative images indicating CD31⁺ vessels, IBA1⁺ microglia, and Ly6G⁺ cells in the primary and grown tumors. Scale bar represents 50μm. e Quantifications of OCT4-, Nestin-, and CD133-positive cells shown in Fig. 1c and CD31-positive vessel numbers, and IBA1- and Ly6G-positive cells (*p < 0.05, **p < 0.01). f Box plots showing enrichment score (ES) for a gene set of neutrophil and macrophage markers of the patients with primary and recurrent GBM (n = 30). g Correlation plots of POU5F1 mRNA levels and neutrophil markers (MPO, CD66B) or macrophage markers (AIF, CD68) mRNA level (n = 30). A Pearson product–moment correlation coefficient (r) was used to determine the linear correlation between two variables. Data in this figure are expressed as means ± standard error of the mean (SEM)