CD33 and glioma: In many solid tumors, including gliomas, CD11b+CD14+CD33+HLA-DR−/lowCo-receptor−/low monocyte-MDSCs (M-MDSC), CD11b+CD15+CD33+Lin−HLA-DR−/low polymononuclear-MDSCs (PMN-MDSC), and a more immature subset of CD3−CD14−CD15−CD19 −CD56−CD33+CD11b+ early-MDSCs (e-MDSC) were described [45,62].