Recent findings that the CD9/CD81 tetraspanin complex regulates α3β1 integrin-dependent tumor cell behavior [45] and that integrin α3β1 promotes breast carcinoma metastases [46] suggests that the anti-metastatic effect observed upon CD9 knockdown could depend on the CD9 regulation of α3β1-integrin. The gene discussed is CD9; the disease is neoplasm.