CTSK and idiopathic pulmonary fibrosis: In the present study, 11 hub genes (COL1A2, COL1A1, COL3A1, SPP1, MMP1, POSTN, ASPN, CDH2, COL14A1, CTSK, MMP7) were found to be associated with the occurrence of IPF using WGCNA, differential gene expression analysis in the training datasets, PPI network analysis, and cytoHubba plugin analyses.