CXCR2 and leukemia: Most neutrophil clusters, however, including clusters 2 (Retnlg + neutrophils), 3 (Cstdc4 + neutrophils) and 7 (Rsad2 + neutrophils) maintained similar levels during leukemia progression, and two other neutrophil clusters, 0 (Il1b + neutrophils) and 12 (Cxcr2 + neutrophils) showed a decrease in the percentage of cells (Fig. 2F).