PLD4 and idiopathic pulmonary fibrosis: From the genes in the brown module, we identified several hub genes associated with IPF, including SPP1, CCR3, FFAR3, CCL2, and STAB1. Using LASSO regression analysis, we further refined the selection and identified 18 genes suitable for constructing the prognostic model, such as CXCR6, BDKRB1, TPST1, PPBP, CLU, CCL2, BMP6, LIPA, CXCL5, CAMP, ELF3, IL1RL1, AOC3, PLD4, S1PR3, CMKLR1, PROK2, STAB1 (Figures 3C,D).