The GFAP-expressing cohort consisted of different cell types, as identified using the cell profile matrix of Darmanis et al.10Since GBM is a tumor of glial origin, GFAP was chosen in order to identify neoplastic cells, normal astrocytes, oligodendrocytes and Oligodendrocyte precursor cells (OPCs) known to express this protein. This evidence concerns the gene GFAP and glioblastoma.