CD33 and neoplasm: Although the unconjugated gemtuzumab antibody had minimal effect on survival (Supp Fig. 3D), Gemtuzumab ozogamcicin induced a dose-dependent decrease in viability (Fig. 4B, C, Sup Fig. 3D and 4A) of M-MDSCs from patients' PBMCs or tumour-polarised CD33+ myeloid cells (Fig. 4D), with no effect on CD33- cells.