ENPP2 and idiopathic pulmonary fibrosis: The result showed that only five genes (aconitase 1 [ACO1], neuroblastoma RAS viral (v-ras) oncogene homolog [NRAS], ectonucleotide pyrophosphatase/phosphodiesterase 2 [ENPP2], mucin 1 [MUC1], and ZFP36 ring finger protein [ZFP36]) remained in LASSO regression from the 19 prognostic FRGs (Figures 4A–C), among which, NRAS, ENPP2, MUC1, and ZFP36 are the risk factors, and ACO1 is a protective factor for IPF prognosis (Figure 4C, Table 1).