Fig. 11. FOXA2 staining of human lung tissue with goblet cell hyperplasia. (A) Photomicrograph (x40) of a small conducting airway of a 5-month-old infant who died with bronchopulmonary dysplasia. The nuclei of Alcian Blue-stained mucus cells are unstained by the FOXA2 antibody. A few cells with FOXA2-stained nuclei are observed in the basal layer of the conducting airways and a nearby terminal airway. (B) Photomicrograph (x10) of the lung from the patient in A, showing a cuboidal lined alveolar duct arising from the small columnar cell lined bronchus. The nuclei of the Alcian Blue-stained mucus cells in the bronchus lack FOXA2, but most of the nuclei of the cells lining the alveolar ducts are FOXA2 reactive. (C) Photomicrograph (x40) of the lung of a 27-year-old female who underwent lobectomy for bronchiectasis. This shows a small bronchus lined with Alcian Blue-stained mucus cells, the nuclei of which lack FOXA2 staining. Many nuclei of non-goblet cells lining terminal airways are FOXA2 reactive. (D). Photomicrograph (x10) of the lung of a 6.5-month-old infant dying with bronchopulmonary dysplasia showing terminal airway cell nuclei immunostained for FOXA2. Nuclei of epithelial cells lining a small conducting airway lack Alcian Blue staining and are immunostained by the FOXA2 antibody. Scale bar: 50 µm.