Figure 5.

Possible mechanism for glomeruloid bodies formation. 1) Low‐grade infiltrating glioma cells coopt pre‐existing microvessels. 2) As the tumor grows, endothelial cells try to resist cooption by releasing Ang‐2, which leads to apoptosis of these cells in the absence of VEGF. Apoptosis of endothelial cells then causes tumor cells to become hypoxic and eventually necrotic, forming initial foci of necrosis. 3) Necrotic niches become surrounded by tumor cells, forming the pattern of pseudopalisading necrosis. Pseudopalisade tumor cells upregulate the expression and secretion of VEGF, which acts on nearby endothelial cells to promote vascular proliferation, leading to the formation of glomeruloid structures.