CXCL8 and glioblastoma: This association between IL-8 and survival was especially pronounced in patients with proneural GBM tumors (Fig. 2d) (proneural subtype: IL-8-down 20.7 months, IL-8-up 9.3 months, HR [95% CI] = 0.54 [0.33, 0.87], log-rank p-value = 0.0109).