A Chinese cohort study reported KL-6 concentration was highly elevated in progressive ILD compared with the non-progressive period (1,985.2 ± 1,497.8 vs. 1,387.6 ± 1,313.1 μg/ml), and increased KL-6 level was the best independent predictor of mortality after adjustment for other covariates (HR 1.901; 95% CI, 1.294–2.793) (21). Here, MUC1 is linked to interstitial lung disease.