Dilli et al. [21] demonstrated that KL-6/14d levels were significantly higher in infants with BPD (155.2 (15.3–545.6) U/mL) than in infants without BPD (7.9 (7.7–15.6) U/mL) (P=0.001). Here, MUC1 is linked to bronchopulmonary dysplasia.