High levels of extracellular TGF-β1 are present in the fibrotic lesions in IPF, and the TGF-β1 activates receptors on fibroblasts to cause them to proliferate and increase the production of extracellular matrix, as well as the production of NEU3 (6, 11, 12). This evidence concerns the gene NEU3 and idiopathic pulmonary fibrosis.