CXCR4 and metastatic neoplasm: The mean weight of metastatic tumors (in g) was dramatically lower in the Lenti-CXCR4-siRNA group than in the SW480 group (1.45±2.07 vs 2.25±2.51, P=0.000) and NC group (1.45±2.07 vs 2.11±2.38, P=0.000).