PRRX1 and idiopathic pulmonary fibrosis: Our results demonstrate that (1) PRRX1 TFs are upregulated in mesenchymal cells accumulating in the fibrotic areas of IPF lungs, (2) the expression of PRRX1 TFs is positively regulated by cues associated with an undifferentiated phenotype in control and IPF primary lung fibroblasts, (3) PRRX1 TFs are required for proliferation as well as proper myofibroblastic differentiation in vitro (see Figure 9 for summary).