We observed increased CD63 expression in the cortex area of LNs of exosome-injected mice (6.75% ± 1.18%) compared with LNs of PBS-injected mice (0.53% ± 0.22%) (P = 0.0001) (Figure 5D), suggesting that cancer exosomes are involved in creating a microenvironment favorable to LN metastasis. This evidence concerns the gene CD63 and cancer.