Similar conclusions were reached using the Secretoglobin Family 1A Member 1 (Scgb1a1)-CreER driver, which labeled clara cells as well as a few scgb1a1 and sftpc dual positive cells and concluded that epithelial cells were not the source of myofibroblasts in bleomycin-induced pulmonary fibrosis. This evidence concerns the gene SCGB1A1 and pulmonary fibrosis.