In contrast to the altered bio- and cell lineage-distribution in WT mice (Fig. 5b, e), CCL2-conjuged BC exosomes exerted no effect on organ distribution (Fig. 5g), lung accumulation (Fig. 5h) or lung CD45.2+ cell uptake (Fig. 5i) in CCR2−/− mice. This evidence concerns the gene CCR2 and breast cancer.