MUC1 and bronchopulmonary dysplasia: Ogihara et al. [14] in their study of 42 infants at <28 weeks of gestational age reported that serum KL-6 levels ≥232 U/mL at postpartum 14 days had an AUC of 0.8995, a sensitivity of 84%, and a specificity of 82% for predicting BPD.