The role of serum KL-6 as sensitive biomarker for various interstitial lung diseases has been demonstrated in idiopathic pulmonary fibrosis, radiation pneumonitis, drug-induced pneumonitis, hypersensitivity pneumonitis, CTD-associated ILD, pulmonary sarcoidosis, and cystic fibrosis [12-15]. This evidence concerns the gene MUC1 and idiopathic pulmonary fibrosis.