SPRR3 and stricture: Gene expression indicated cellular processes typical of tracheal stenosis, such as hyperproliferation (due to downregulated CRNN and CAPN14 causing decreased cell-cycle regulation), hypergranulation (due to downregulated SPRR3, RPTN, TGM3, and SLURP1 causing dysregulated keratinization), and extracellular matrix remodeling (upregulated MMPs and HAS1).