Figure 1

Invasive behavior of human GBM cells in mouse orthotopic transplantation. Hematoxylin and Eosin (HE) staining (A, C, E) and immunofluorescence analyses (B, D, F) of mouse brains injected with human cultured GBM cells. The immunofluorescence analyses were performed with an anti-human nestin antibody. Human nestin, yielding a green signal, identify GBM cells within the host tissue. Nodular-like growth pattern at 8 weeks post-injection, NL-type 8w (A, B; PT2). Highly diffuse and invasive growth pattern at 8 and 14 weeks post-injection, HD-type 8w (C, D; PT6) and HD-type 14w (E, F; PT6). The asterisks indicate the striatum in (C, D). Higher magnification images of the areas whose corners are indicated by four (L) in (C, D) are shown in (C’, D’). Arrowheads indicate tumor nodules in (A, B). Notice in (C, D) scattered human nestin-positive GBM cells and lack of nodules. Notice in (E, F) the complete substitution of the host’s tissue by the engrafted human nestin-positive GBM cells. Arrows in (E, F) indicate brain midline. Scale bar = 500 μm in (A-F). Scale Bar = 200 μm in (C’, D’).