We also observed that the differentiation capacities of the A2B5+ cells differed according to the histological types: A2B5+ cells from pilocytic astrocytoma, and to a lesser extent those isolated from GBM, had differentiation capacities reminiscent of normal O-2A cells in culture but never expressed MBP (myelin basic protein), a maker of mature oligodendrocytes. This evidence concerns the gene MBP and pilocytic astrocytoma.