The CXCL12 expression in datasets from TCGA-glioblastoma and CGGA-mRNA-325 indicated elevated levels of CXCL12 in glioblastoma compared with normal tissues (Fig. 1C) and in recurrent gliomas compared with treatment-naïve gliomas (Fig. 1D). This evidence concerns the gene CXCL12 and central nervous system cancer.