S100A8 and neoplasm: Due to the increased Gr1+CD11b+Ly6G+ neutrophils and S100A8/A9 proteins, the lungs of BALB/c mice bearing 67NR, 4T07, or 4T1 tumor can actively recruit intracardially injected 4T1-Luc2-tdTomato metastatic breast cancer cells (Fig. 6b).