To validate these findings, a separate cohort of 8 GBM tumors were analyzed by flow cytometry using a human panel previously validated, where M-MDSCs were identified by the following gating strategy singlets/live/HLA-DR−/CD33+/CD11b+/CD14+/CD15− and G-MDSCs by singlets/live/HLA-DR −/CD33+/CD11b+/CD14−/CD15+. This evidence concerns the gene CD33 and glioblastoma.