MUC1 is activated by extracellular ligands such as intracellular adhesion molecule-1 (ICAM-1), which interacts with the protein component of the MUC1 VNTR or MUC1 N-terminal domain [60], and which was elevated in the serum of IPF patients [61]. This evidence concerns the gene MUC1 and idiopathic interstitial pneumonia.