PTPRZ1 and glioblastoma: To validate our SAGE results, we performed qRT-PCR of several genes listed in Table 1 and Table S1 (DUSP6, PODXL, PTPRZ1, FABP7, FAM70A, and MAN1C1) in the original line utilized for the SAGE analysis as well as in two additional GBM stem-like cell lines before and after differentiation.