By analyzing the expression of macrophage marker (F4/80) and M2-type macrophage marker (CD206) in the IV2 xenograft tumors, we found that compared to the IgG1 control group, tumors with CXCL7 antibody injection displayed significantly reduced number of F4/80 or CD206 positively labeled cells (Fig. 4E, F), demonstrating that CXCL7 could act as an important modulator to promote breast cancer progression through promoting the recruitment of TAMs. Here, PPBP is linked to breast cancer.