FOXO1 and idiopathic pulmonary fibrosis: Interestingly, when we analyzed FoxOs mRNA expression, FOXO3 was the most abundant form (Appendix Fig S1A) and was significantly downregulated in IPF‐HLF compared to N‐HLF (Fig 1C), whereas the level of FOXO1 and FOXO4 were unchanged (Appendix Fig S1B).