MUC1 and idiopathic pulmonary fibrosis: Serum concentrations of KL-6 were higher in IPF-LC than IPF patients at t0 (p = 0.0002) (Table 1) and ROC curve analysis distinguished these two groups (AUC 92%; 95% CI 78-100; p = 0.0005), indicating a best cut-off value of 1370 U/mL (83% sensitivity, 92% specificity) (Figure 2).