CRABP2 and idiopathic pulmonary fibrosis: As a proof-of-concept to demonstrate the translational relevance of our study, we selected cellular retinoic acid-binding protein 2 (CRABP2), one of the novel intramodular hubs that is (a) upregulated in IPF lungs; (b) differentially expressed across different IPF severity levels; (c) part of the novel candidate genes that are capable of distinguishing fibrotic samples from healthy controls in the two training cohorts and two other independent validation studies (GSE150910 and GSE134692); (d) shows cell-specific expression; and (e) encodes a secretory protein (Figure 5).