Western blot results showed that the more CAV1 in BC sEVs, the higher the levels of p-Src and p-PI3K, under the condition of the unchanged expression level of CAV1 in lung epithelium; incubation of BEAS-2B cells with BC sEVs that overexpress CAV1, p-Src and p-PI3K were reduced in the knockdown CAV1 group in lung epithelial cells compared with BEAS-2B cells typically expressing CAV1 (Fig. 4f). Here, CAV1 is linked to breast cancer.