These cells also express other basal cell markers such as p63, LAMB3, and LAMC2, as well as markers of epithelial-mesenchymal transition (eg, COL1A1, VIM, TNC, FN1, CDH2), and senescence (eg, CDKN1A, CDKN2A, and GDF15), in addition to MMP7, a well-established biomarker in IPF.7 The gene discussed is GDF15; the disease is idiopathic pulmonary fibrosis.