Table 2.

Overview of molecules associated with the immune microenvironment of DMG

Factor type	Factor	Findings	Reference
Chemoattractant or inflammatory	CXCL1, CXCL2, CXCL5, CXCL6	Human DMG tissue samples showed significant gene expression of the CXCR2 pathway, which includes CXCL1, CXCL2, CXCL5, and CXCL6 as compared to other human pHGGs	[12]
Recruitment	CCL2, CCL5, CXCL12	Analysis of single-cell DMG gene expression and secreted protein levels from biopsy tissue included CCL2, CCL5, and CXCL12	[20]
	CCL3, PDGFß	High PDGFß levels in human DMG tissue samples are linked to an increased presence of IBA1 + TAMs. In a murine PDGFß-driven tumor model, CCL3 knock-out provided survival benefit	[75]
	IL-8	Ross et al. found increased IL-8 gene expression in human DMG tissue samples. Lieberman et al. found that IL-8 was significantly increased over normal and pLGG in surgery and autopsy DMG tissue, but lower than pHGG	[12, 19]
Immune regulatory	CSF-1, TGF-ß	Analysis of single-cell DMG gene expression and secreted protein levels from biopsy tissue included CSF-1 and TGF-ß	[20]
Cell proliferation or migration	PDGFA	Analysis of single-cell DMG gene expression and secreted protein levels from biopsy tissue included PDGFA	[20]
	B7-H3, VEGF-A	Within the tumor microenvironment of surgery and autopsy DMG tissue, factors associated with immunosuppression B7-H3 and VEGF-A were increased relative to control	[19]

C-X-C motif ligand (CXCL); diffuse midline glioma (DMG); C-X-C chemokine receptor (CXCR); C-C motif ligand (CCL); platelet-derived growth factor-beta (PDGFß); ionized calcium binding adaptor molecule 1 (IBA1 +); interleukin-8 (IL-8); pediatric low-grade glioma (pLGG); pediatric high-grade glioma (pHGG); colony-stimulating factor 1 (CSF-1); transforming growth factor-beta (TGF-ß); platelet-derived growth factor subunit A (PDGFA); B7 homolog 3 protein (B7-H3); vascular endothelial growth factor A (VEGF-A). For GBM, an overview of the key molecules associated with the microenvironment has been published recently [131].