Figure 1.

Vascular co-option. A: Temporally, vascular co-option is the first process by which gliomas attain a vascular supply. The process involves organization of tumor cells into cuffs around normal microvessels (inset). Vascular co-option has been shown to precede angiogenesis in tumor models by up to 4 weeks. B: Photomicrographs of tumor cells in a sectioned human GBM specimen stained with H&E show vascular co-option as classic perivascular cuffs. Original magnification: ×50 (top); ×200 (bottom).