S100A4 and idiopathic pulmonary fibrosis: As an important member, S100A4 was reported to have an abnormal expression in several lung diseases, such as lung cancer, pulmonary hypertension, idiopathic pulmonary fibrosis (IPF), etc. For example, in lung cancer, S100A4 was demonstrated to be associated to metastatic tumor progression and epithelial to mesenchymal transition (EMT).