MZB1 and acute leukemia: Myeloperoxidase (MPO)/lysozyme (LYZ) and marginal zone B and B1 cell-specific protein (MZB1)/brain and acute leukemia, cytoplasmic (BAALC) were respectively activated in the granulocyte-macrophage progenitor (GMP) and multilymphoid progenitor (MLP) clusters (Figure 1D and Supplemental Figure 2A).