Since SFTPC is a recognition protein for integrin α6β4 on BC sEVs in the lung, and integrin α6β4 on sEVs binds to SFTPC in lung epithelial cells, resulting in sEVs translocation to the lung26, we hypothesized that CAV1 may promote the internalization in BC sEVs by BEAS-2B cells by regulating the expression of integrin α6β4 on BC cells and sEVs. Here, SFTPC is linked to breast cancer.