Even though we used a very controlled model with only three variables (native/PLX-pretreatment, dexamethasone treatment, CXCR2-inhibition), the effect on S635 GBM cell line outgrowth is highly context-dependent and interactive due to interrelations and/or synergistic effects of the factors (humoral, cellular, and drug treatment). This evidence concerns the gene CXCR2 and glioblastoma.