To rigorously investigate the in vivo role of ECs in IL-6 expression as well as IL-6’s functions in GBM progression, we generated a conditional IL-6 knockout Cdh5-CreERT2;Il6fl/fl mouse line, in which IL-6 knockout was induced by tamoxifen-inducible CreERT2 expression under EC-specific Cdh5 promoter (Fig. 7a). This evidence concerns the gene IL6 and glioblastoma.