SPP1 and pulmonary fibrosis: Recent years, it has been found out that SPP1 expression has been upregulated in bleomycin-mediated models of pulmonary interstitial fibrosis (24, 25), mouse models of asbestos lungs (19), and irradiation-induced models of interstitial fibrosis (26), suggesting that SPP1 may have played a certain regulatory role in the progression of pulmonary fibrosis.