Exosomal S100A8/A9, released upon CCL2 stimulation in the primary tumor, can be delivered systemically to the pre-metastatic lung endothelium, and potentially stimulate the paracrine production of mediators such as serum amyloid A3 (SAA3), attracting further CD11b+ cells to the lung 10. This evidence concerns the gene CCL2 and neoplasm.