The cell of origin in glioblastoma is not formally proven but generally accepted to be a neural stem cell or glial precursor cell. In addition, there is also limited knowledge about the functional consequences of the cell of origin for glioblastoma development and response to therapy. We have investigated the role of cell of origin in glioblastoma by inducing glioblastomas of defined cell of origin using PDGFB in the brains of adult mice. Gene expression was analysed from cultured mouse glioblastoma cells and a mouse cell origin gene signature was extracted that we used in a cluster analysis on gene expression data from patient-derived glioblastoma cell lines. Overall design: Gene expression was analyzed on a panel of 61 patient-derived glioblastoma cell lines. All cells were cultured adherently under stem cell conditions.