TGFB1 and neoplasm: Second, TGF-β and IL-10, which are closely related to tumor cell invasion, are increased in the exosomes of metastatic small cell lung cancer cells, and this activates SMAD, phosphatidylinositol 3-kinase (PI3K)/AKT, BRAF-MAPK, and other signaling pathways, thereby promoting tumor metastasis.76