The mechanism by which thrombolytic tPA might lead to hemorrhagic transformation of ischemic stroke is not completely understood, but it appears to be due in part to unique activities that tPA has in the brain beyond its well established role in fibrinolysis (Nicole et al., 2001; Wang et al., 2003; Yepes et al., 2003; Su et al., 2009). The gene discussed is PLAT; the disease is ischemic stroke.