HPCAL1 and pulmonary fibrosis: In addition, the selected biomarkers showed good differential expression in the training set and test set, the expression levels of FHL2 were elevated in the idiopathic pulmonary fibrosis group (Fig. 5A), while the expression level of SLAIN1, HPCAL1, and RNF182 were reduced in the idiopathic pulmonary fibrosis group (Fig. 5B–D).