As most of the putative glioma CSC associated markers (e.g. CD133, CD15, A2B5 and CD44) are not unique to tumour cells but are also expressed by stromal cells [19], we used spheroid-based xenografts in eGFP+ NOD/Scid mice for a distinct analysis of pure tumour cell populations. This evidence concerns the gene PROM1 and glioma.