To address this, in vitro experiments were conducted using Luc2 cells (highly metastatic mouse mammary carcinoma cells) as donor cells of CD44-positive extracellular vesicles and UV2 cells (mouse hemangioendothelioma-like endothelial cells) as recipient cells, and optimal extracellular vesicle formulations were constructed. This evidence concerns the gene CD44 and breast carcinoma.