CXCR4 and glioblastoma: In the GBM-sp (Figure 3a), the GSC markers STAT3, SOX2, PROM1, POU5F1, PDGFRA, NOTCH2, MYC, MSI1, L1CAM, ITGA6, CXCR4, and CD44 were significantly expressed in all cell lines (Figure 3b).