To determine whether SOX9 is upregulated during TGF-α–induced pulmonary fibrosis, we measured the Sox9 levels in the total lung transcripts of TGF-α–overexpressing (TGFαOE) mice that developed severe fibrotic lung disease by 28 days after doxycycline (Dox) treatment (10). This evidence concerns the gene SOX9 and pulmonary fibrosis.