MUC5B and idiopathic pulmonary fibrosis: The role of this gene in the pathogenesis of IPF has not been fully elucidated, although mechanistic studies suggest that overexpression of MUC5B, driven by the promoter polymorphism, increases chronic mucus hypersecretion, impairs mucociliary clearance in the broncho-alveolar region, and potentiates chronic inflammation and injury [51].