So, we conclude that CAV1 in BC-derived sEVs promote neutrophil recruitment through the TLR4-NF-κB-IL-6/CCL2 axis and neutrophil N2-type polarization through the TLR4/NF-κB/NLRP3 pathway, thus promoting the lung metastasis of breast cancer. The gene discussed is CCL2; the disease is breast carcinoma.