TGFB1 and lung cancer: Exosomes carry proteins and genetic material and play important roles in signal transduction between cells.21 In the present study, we found that exosomes extracted from the cell culture supernatant TGF‐β‐pretreated A549 cells were capable of increasing the metastatic potential of lung cancer cells and enhancing vascular endothelial cell permeability, indicating that exosomes derived from lung cancer cells with high metastatic potential could affect other lung cancer cells and regulate vascular permeability.