We found that a Cdc42/Rac1 GTPase Inhibitor, ML141, significantly decreased the uptake of both types of EVs by astrocytes, whereas a specific Rac1 inhibitor, CAS 1177865-17-6, had no effect on their uptake, suggesting that Cdc42, but not Rac1, is involved in the uptake of breast cancer-derived EVs (Figure 1B). This evidence concerns the gene RAC1 and breast cancer.