In addition to the CCR7-mediated CNS infiltration, the exosomes isolated from a T-ALL cell line P12 but not the B-cell acute lymphoblastic leukemia (B-ALL) cell lines facilitate CNS invasion across the blood–cerebrospinal fluid (CSF) barrier without disrupting the barrier integrity [121] (Figure 2C), highlighting the contribution of T-ALL-derived exosomes to CNS infiltration, although further studies are needed to clarify the molecular mechanisms. Here, CCR7 is linked to acute lymphoblastic leukemia.