TGFB1 and idiopathic pulmonary fibrosis: Differential gene expression analysis of untreated ILD biopsy versus control (nondiseased) donor and untreated ILD biopsy versus IPF explant fibroblasts demonstrated transcriptional upregulation of numerous individual genes involved in the TGF-β pathway (Figure 1, D–F, Supplemental Figure 2, B–D, and Supplemental Table 3).