Furthermore, exosomal TGF-β from SGC-7901 cells has been proven to lead to the activation of the Smad pathway, and the succedent differentiation of human umbilical cord mesenchymal stem cells (hucMSCs) into cancer-associated fibroblasts (CAFs) through interacting with TGF-βR1 in hucMSCs [103]. Here, TGFB1 is linked to cancer.