Additionally, M2-polarized microglia released insulin-like growth factor-binding protein 1 (IGFBP1), which was induced by upregulation of macrophage colony-stimulating factor (MCSF) in a spleen tyrosine kinase (SYK)-PI3K-NFκB-dependent manner in GBM and promoted angiogenesis. This evidence concerns the gene IGFBP1 and glioblastoma.