TGFB1 and pulmonary fibrosis: Association of TGF-β1 polymorphism with susceptibility to various diseases such as autoimmune disease, infectious disease, and cancer has been previously reported.[14,23] Given the fact that the levels of TGF-β1 in blood or in injured lung were higher in patients with pulmonary fibrosis than that in healthy controls,[24] multiple studies have reported conflicting results regarding the association of TGF-β1 polymorphism with pulmonary fibrosis.