Through a single cell transcriptomic profiling, the authors demonstrated in several breast cancer preclinical models and cancer patients that these clusters comprise neutrophils with a N2-like signature, resembling PMN-MDSCs expressing ARG1, chemokine (C-X-C motif) ligand 2 (CXCL2), CCL2, VEGFA and endowed with pro-tumoral activity. This evidence concerns the gene ARG1 and cancer.