Immunofluorescence for FSP- and Ki67 in lung sections of control and bleomycin treatment groups also showed increased Ki67 expression in FSP-1+ cells in bleomycin-induced pulmonary fibrosis (Fig. 4C), suggesting that lung fibroblast proliferation is increased in bleomycin-induced pulmonary fibrosis. The gene discussed is MKI67; the disease is pulmonary fibrosis.