BC-derived exosomal microRNA-200b-3p uptaken by alveolar epithelial type II cells (AEC II) induces the high expression of CCL2, S100A8/9, MMP9, and CSF-1 in the lung to recruit myeloid-derived suppressor cells (MDSCs) and promote inflammatory pre-metastatic niche formation [324]. This evidence concerns the gene CCL2 and breast cancer.