The human alveolar epithelial cell line A549, and two different cell lines of human fibroblast, one derived from an IPF patient (LL-29) and the other from healthy fibroblast (MRC5), were treated with TGF-β1, and the correlation between expression of AQP1 and other proteins were analyzed to determine their role in the induced EMT or fibroblast-myofibroblast transition process. Here, AQP1 is linked to idiopathic pulmonary fibrosis.