Fig. 2
Role of miRNAs in EVs in the cancer microenvironment. Through the transfer of miRNAs, EVs mainly promote tumorigenesis. Tumor-derived EVs can activate endothelial cells to promote angiogenesis or vascular permeability. Tumor-derived EVs can convert fibroblasts into CAFs. In return, CAF-derived EVs can confer proliferation or drug resistance to tumor cells. Tumor-derived EVs can contribute to creating an immunosuppressive microenvironment by impairing the function of immune cells. In another aspect of the immune system, tumor-derived EVs can mobilize TAMs to promote cancer progression. Moreover, tumor-derived EVs can provide drug resistance or proliferation to surrounding other tumor cells. In contrast, noncancerous cell-derived EVs also participate in the tumor microenvironment. EVs derived from MSCs contribute to long-term metastasis by inducing a dormant state in cancer cells. EVs derived from normal epithelial cells can suppress cancer proliferation