In the acute stage of stroke (within 24 hours), infiltrating immune cells release proinflammatory cytokines (IL-1β, IL-6, TNF-α), chemokines (MCP-1, MIP-1α, IL-8), reactive oxygen species (ROS), and matrix metalloproteinase (MMP) (mainly MMP-9), which amplify neuroinflammatory responses and lead to brain edema, neuronal death, and disruption of blood-brain barrier (BBB).8,9,11 However, some of these molecules have a different role in the later stage of stroke (after 24 hours). The gene discussed is MMP9; the disease is Stroke.