Fibronectin CS-1 peptide binds α4β1 integrin; it exhibits pro-metastatic and immunomodulatory activities. Fibronectin CS-1 peptide is involved in oral squamous cell carcinoma pathogenesis, regulating migration and invasion. This peptide may increase expression of matrix metalloproteinases (MMPs). In vitro, fibronectin CS-1 peptide stimulates proliferation of T cells. In animal models of cerebral ischemia/reperfusion, fibronectin CS-1 peptide decreases leukocyte infiltration in lesioned areas, decreasing infarct size.