To determine whether any universal GAM marker might be identified, we set up a comparative analysis of four publically available data sets: (a) MACS sorted CD14+ from human GBM versus postmortem tissue and low grade gliomas profiled with microarrays (2); (b) MACS sorted CD11b+ from human GBM versus postmortem and epilepsy tissue analyzed by RNA-seq (3); (c) MACS sorted CD11b+ from murine GL261 GBM profiled with microarrays (5); (d) FACS sorted CD11b+/CD45low from rat C6 gliomas profiled with microarrays (6). This evidence concerns the gene GLS and central nervous system cancer.