Our results differ from a recently presented report that KLF4 deletion from fibroblasts protected from early lung fibrosis (49); however, in that study, tamoxifen was administered prior to bleomycin, and thus, those data focus on potential roles of KLF4 during the early phases postinjury, rather than focusing on the fibrotic phase of the response as we did. The gene discussed is KLF4; the disease is pulmonary fibrosis.