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Fig 7. Schematic representation of the formation of a pseudopalisade. Growth of the glioblastoma stimulates neo-angiogenesis. Expression of ang 2 causes endothelial damage, which, in turn, produces vascular occlusion and hypoxia. Cells unable to survive the hypoxia succumb and form the nidus of coagulation necrosis. Other cells, however, migrate to the periphery of the hypoxic field in waves forming pseudopalisades. The migrating hypoxic cells secrete VEGF, proteases, and other factors that cause further microvascular proliferation and enhanced invasiveness in regions ringing the hypoxic field. These latter effects prompt further aggressive outward expansion of the glioblastoma cells (modified with permission from Brat et al42).
