IGF1 and pulmonary fibrosis: The upregulated expression of IGF1 was validated by immunohistochemistry staining results in our study, and previous findings showed that IGF1 level increased in the bronchoalveolar lavage fluid of patients with IPF and the murine pulmonary fibrosis model, suggesting that IGF1 is involved in the pathogenesis of disease where fibrosis is the predominant feature.