PAI-1, an endogenous inhibitor of urokinase-type plasminogen activator (uPA), is known to play a major role in benign disorders such as deep vein thrombosis, myocardial infarction, atherosclerosis, and stroke, and more recently has been linked to some cancers [17], including colorectal cancer. This evidence concerns the gene SERPINE1 and deep vein thrombosis.