Fig. 3.

Histological features of GBM xenograft models. (A) GBM patient biopsies may be processed to yield adherent cell lines in serum-containing medium, which results in an extensive clonal selection and cellular adaptation process. Xenografts generated from such cell lines will display angiogenic growth and well-defined borders toward the brain tissue. No single tumor-cell invasion is seen (the example here is from the U-87 glioma cell line). (B) Enzymatic dissociation of patient biopsies with subsequent culture in neurobasal serum-free medium selects for a highly tumorigenic subpopulation in human GBM. In several instances, the resulting xenografts are highly infiltrative, following white matter tracts and spreading over the corpus callosum.²⁴ (C) The biopsy xenograft model maintains several tumor cell clones from the biopsy, as well as other cell types and extracellular matrix components. When passaged extensively in immunodeficient animals, the xenografts maintain their invasive growth and develop other characteristics of human GBM, such as dilated vessels, angiogenesis, and pseudopalisading necrosis. Scale bars: 100 µm.