KRT17 and idiopathic pulmonary fibrosis: Cells positive for the canonical basal cell marker KRT17, KRT5 and tumor protein 63 (p63), or secretory (secretoglobin family 1A member 1 (SCGB1A1)+, MUC5B+)- or ciliated (AcTub+) epithelial cells were detected within distal bronchioles of non-fibrotic controls tissue and within HC in IPF tissue (Fig. 1B).