TGFB1 and pulmonary fibrosis: A similar theory can also explain the observation that integrin β6−/− mice have only minor lung fibrosis in response to bleomycin induction.105 Because the lungs are a highly contractile organ and its compliance is closely associated with the force-directed activation of TGF-β, β6 deletion directly disrupts intracellular anchorage, and thus may significantly retard the activation of TGF-β and lung fibrosis.