However, as we found that the concentration of bFGF required to drive fibroblast migration was much higher compared to that needed to induce proliferation, it is possible that at physiological levels increased bFGF in IPF co-cultures could induce proliferation of sub-epithelial IPF fibroblasts without necessarily inducing their transmigration into epithelial wounds. Here, FGF2 is linked to idiopathic pulmonary fibrosis.