To assess the presence and extent of EMT in bleomycin induced pulmonary fibrosis model, expression levels of E-cadherin and fibronectin were analyzed in sections of lung tissues from mice administrated with saline or bleomycin in wild-type group and KLF4-overexpressing transgenic group with double-label immunofluorescent staining method. The gene discussed is FN1; the disease is pulmonary fibrosis.