CXCL8 and glioblastoma: Multivariable stepwise Cox proportional hazards model confirmed IL-8 as an independent prognostic survival factor in all GBM patients, specifically those with proneural tumors (Figs 2b–d, right panel) (HR [95% CI]: all GBM 1.07 [1.01, 1.14], p = 0.0467; proneural subtype 1.19 [1.04, 1.37], p = 0.014) independent of IDH mutation status (Supplementary Figure S2).