FAP and esophageal squamous cell carcinoma: ,44 These cells are then activated by factors under the TME conditions, such as transforming growth factor β (TGF-β), platelet-derived growth factor, sonic hedgehog, and other genes to differentiate into CAFs.44, 45, 46 Using co-culture experiments, we observed in this study that NFs exhibited activated phenotypes, including the increased expression of α-SMA and FAP and the ability to promote ESCC cell proliferation.