Fig. 3.

Low-magnification images of peri-arteriolar GSC niches in paraffin-embedded sections (niche 1) and cryostat sections (niche 2) of GBM. Serial sections of GBM were screened for GSC niche regions after IHC staining of the stem cell marker CD133 (a, d) at a low magnification (×4). GSC niches were identified by immunolabelling of SMA for smooth muscle cells of arterioles (b, e) and the cytokine and niche factor SDF-1α (c, f). Niche 1 and niche 2 were found in different GBM patient samples. Immunohistochemical labelling of SMA in paraffin-embedded sections was performed with AEC as chromogen (b; red color) and of SMA in cryostat sections and other antigens with DAB as chromogen (a, c-f; brown color). Cell nuclei were counterstained using haematoxylin (blue/purple). Niches are marked by rectangles. a arteriole. Scale bar = 200 µm. (Color figure online)