KLF9 and idiopathic pulmonary fibrosis: NFE2L2 (NF-E2–related transcription factor 2, also called NRF2) stimulation increases the expression of KLF9 (Kruppel-like factor 9), resulting in increases in ROS production and subsequent cell death, however they show diverse functions in bleomycin-induced pulmonary fibrosis in mice (Cho et al., 2004; Hecker et al., 2014; Zucker et al., 2014) and IPF (Artaud-Macari et al., 2013).