MUC1 and chronic obstructive pulmonary disease: Recent studies have established that MUC1 or its released fragment, KL6 are prominent membrane markers mediating the expression of anti-inflammatory genes in interstitial lung diseases, asthma, COPD and lung cancer (Ishikawa et al., 2011; Ishikawa et al., 2012; Milara et al., 2018; Milara et al., 2019).