This study investigated the effects of small interfering RNA(siRNA)-mediated silencing of chemokine receptor 4(CXCR4)on the invasion capacity of human neuroblastoma cell line SHSY5 Y in vitro.Three siRNAs targeting CXCR4 were chemically synthesized and individually transfected into SH-SY5Y cells.Expression of CXCR4 mRNA and protein was significantly suppressed in transfected cells by all three sequence-specific siRNAs compared with control groups.Furthermore,the invasion capacity of SH-SY5Y cells was significantly decreased following transfection with CXCR4-specific siRNA compared with the control groups.These data demonstrate that down-regulation of CXCR4 can inhibit in vitro invasion of neuroblastoma. This study investigated the effects of small interfering RNA (siRNA) -mediated silencing of chemokine receptor 4 (CXCR4) on the invasion capacity of human neuroblastoma cell line SHSY5 Y in vitro. Thh siRNAs targeting CXCR4 were synthesized and individually transfected into SH-SY5Y cells. Expression of CXCR4 mRNA and protein was significantly suppressed in transfected cells by all three sequence-specific siRNAs compared with control groups. Further, the invasion capacity of SH-SY5Y cells was significantly decreased following transfection with CXCR4-specific siRNA compared with the control groups. these data demonstrates that down-regulation of CXCR4 can inhibit in vitro invasion of neuroblastoma.