We further examined associations between miR-503 expression and fibroblast production of IL-6, -8, prostaglandin (PG)E2, hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), vascular endothelial growth factor (VEGF) and fibronectin, all of which have been suggested to contribute to COPD pathophysiology [8, 11, 18–21]. Here, IL6 is linked to chronic obstructive pulmonary disease.