Plasminogen activator inhibitor-1 (PAI-1, also known as serpine E1) is an inhibitor of fibrinolytic system exerting several physiological and pathophysiologial effects related to tumorigenesis, inflammation, thrombosis and metabolic disturbances such as obesity and insulin resistance [36]. Here, SERPINE1 is linked to obesity due to melanocortin 4 receptor deficiency.