CXCL1 and glioblastoma: The above results indicate that MDK secreted by EGFRvIII-mutant GBM can activate macrophage surface receptor LRP1 and downstream pathways to drive macrophages towards the immunosuppressive M2 subtype polarization, while promoting macrophage secretion of immunosuppressive cytokine CXCL1 and promoting immune escape of GBM.