PTEN and gastric cancer: Zheng et al. (2017) demonstrated that the exosome-like vesicles that were isolated from M2 macrophages had the ability to confer cisplatin resistance to gastric cancer cells through the transfer of miR-21, which resulted in phosphatase and tensin homolog (PTEN) downregulation and the inhibition of PI3K/Akt signaling [189].