CD33 and chronic myelogenous leukemia, BCR-ABL1 positive: To date, G-MDSCs defined as CD11b+CD14−CD33+CD15+ [18], CD33+CD11b+HLA-DRlow/−CD15+ [19], and CD11b+CD14−HLA-DRlow/−CD33+CD15+ [20] cells have been identified in the mononuclear cell fraction of peripheral blood and bone-marrow samples from multiple myeloma patients, while CD11b+CD33+CD14− G-MDSCs have been isolated from the peripheral blood mononuclear cell fraction [21] and whole peripheral blood [22] of chronic myeloid leukemia patients.