[Comment] Hedgehog signalling: on the way to curing idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible lung disease associated with poor quality of life, reduced survival, and substantial health-care use.1 Although the exact cause or causes of IPF remain unknown, our understanding of disease pathogenesis has improved substantially in the past 20 years. The current disease paradigm involves recurrent alveolar epithelial injury triggered by various factors, including genetic predisposition, environmental exposures, and ageing-related changes, followed by abnormal activation of fibroblasts and their differentiation to myofibroblasts, leading to excessive extracellular matrix production and lung remodelling.