However, since glioma cells also express glial markers, we confirmed their host origin using three different approaches: 1) Control fluorescence microscopy for host cell GFP expression following every sorting, 2) Immunofluorescent staining confirming the absence of the pan-human specific marker Human Nuclear factor (HuNu) in the stromal compartment, and 3) By implanting GFP+ CD11b− CD31− cells in NOD/scid mice, which were non-tumourigenic compared to the implanted glioma cells. This evidence concerns the gene PECAM1 and central nervous system cancer.