In a recent preprint paper from Haberman et al. [40], single-cell data from nonfibrotic controls and pulmonary fibrosis samples, including IPF, chronic hypersensitivity pneumonitis, nonspecific interstitial pneumonia, sarcoidosis and unclassifiable interstitial lung disease, were evaluated to identify four secretory cell phenotypes: SCGB1A1+MUC5B+MUC5AC+ cells; SCGB1A1+MUC5B+ cells; SCGB1A1+SCGB3A2+ cells and SCGB3A2+ only cells. The gene discussed is MUC5AC; the disease is pulmonary fibrosis.