In our previous studies of ischemic stroke we have found that the protease tissue-type plasminogen activator (tPA) induces opening of the BBB through proteolysis of latent platelet derived growth factor-CC (PDGF-CC), generating an active form of PDGF-CC that binds to the PDGFRα and induces cell signaling (Su et al., 2008). The gene discussed is CXCR1; the disease is ischemic stroke.