To answer this question, coronal brain sections of glioma-bearing mice treated with 3 × 108 or 3 × 109 sEVs derived from BV2 cells were analyzed for the expression of the proliferation marker Ki67 by immunofluorescence: the data reported in Figure 3C,D showed a significant reduction of Ki-67 staining upon treatment with both 3 × 108 and 3 × 109 sEVs (derived from 106 and 107 BV2), and the numbers of proliferating cells were significantly different between the two treatments. This evidence concerns the gene MKI67 and central nervous system cancer.