Furthermore, the secretion of transforming growth factor-β1 (TGF-β1) PAAD cells has been observed to induce the expression of FAP in hitherto quiescent PSCs, thereby promoting a further releasing CXCL1, promoting tyrosine kinase receptors phosphorylation, and forming a positive feed-forward loop promoting PAAD progression (47). This evidence concerns the gene FAP and pancreatic adenocarcinoma.