Tumor-induced vascular vessels commonly have abnormal structure with increased permeability and incomplete cellular junction . Zhou et al. showed that in endothelial monolayers, exosomal miR-105 derived from breast cancer cells efficiently destroyed tight junctions and the integrity of natural vascular endothelial barriers by targeting ZO-1 in ECs, thus promoting breast cancer metastasis . Similarly, lung cancer cells-secreted exosomal miR-23a also inhibited tight junction protein ZO-1, thereby increasing vascular permeability and cancer trans-endothelial migration . Collectively, these observations suggest that tumor-secreted EV miRNAs participate in intercellular communication and function as a novel pro-angiogenic mechanism.