HTRA1 and idiopathic pulmonary fibrosis: Since IPF is closely related to EMT-related processes, the intersection between the 110 DEGs and 200 EMT-related genes from the MSigDB was determined (Supplementary Table S4), and four related genes were obtained, namely, secreted phosphoprotein 1 (SPP1), integrin beta-3 (ITGB3), high temperature requirement 1 (HTRA1), and tissue inhibitor of metalloproteinase 3 (TIMP3), which were significantly altered in IPF; these were plotted using a Venn diagram (Figure 2B).