CCL2 and neoplasm: For instance, hypoxic tumor cells produce exosomes that are highly enriched in immunoregulatory cargos, including proteins and chemokines, such as colony-stimulating factor 1 (CSF-1), chemokine (C-C motif) ligand 2 (CCL2), ferritin H, ferritin L, and transforming growth factor β (TGFβ) [24].