Chow et al. (2014) demonstrated that exosomes derived from MDA-MB-231 and MCF7 breast cancer cell lines have the ability to hijack lung macrophage activity by activating the NF-κB pathway, resulting in the expression of the pro-inflammatory markers IL-6, TNFα, G-CSF and CCL2 and promoting lung metastasis in vivo [63]. Here, CCL2 is linked to breast cancer.