OBJECTIVE To discuss the application of the slow virus-induced short-hairpin RNA （vshRNA） to silence the expression of CXCR4 in EsCa cell lines Eca109, and observe the effect of silencing CXCR4 on the proliferation and apoptosis of Eca109 cells in vitro. METHODS The expression plasmid of vshRNA targeting CXCR4 was constructed, with a concurrent construction of negative vshRNA expression plasmid, and without targeting any known mRNA. Real-time quantitative PCR and Western blot assay were used to determine the change of CXCR4 expression in the post-transfected EsCa cell Eca109, and MTT assay was conducted to detect the change of proliferation in EsCa Eca109 cell after silencing the CXCR4. The .ow cytometry was used to detect the change of the cell cycle and apoptosis in the post-silenced EsCa Eca109 cell in di. erent groups. RESULTS The transfection rate was respectively （87.3 ± 1.2）% and （90.1 ± 1.4）% in the CXCR4- RNAi-LV （silent group） and NC-GFP-RNAi-LV （negative control group） cellular plasmids. The vshRNA interference resulted in a down-regulation of the CXCR4 gene mRNA and protein expressions in Eca109 cells. CXCL12 promoted the proliferation of EsCa cell lines Eca109. The speed of EsCa cell proliferation became slower in the silencing group than in the normal control （also the control） and the negative control groups （P 〈 0.05）. However, there was no significant difference in comparison of the proliferation speeds between the negative control and the normal control groups （P 〉 0.05）. In the silencing group, the proportion of the cells in phase G0/G1, phase S and phase G2/M was respectively （69.9 ± 5.0）%, （17.1 ± 2.5）% and （13.0 ± 7.4）%, and the apoptotic rate achieved （7.27 ± 0.50）%. In the normal control group, the proportion of the cells in phase G0/G1, S and G2/M was respectively （55.9 ± 4.6）%, （30.2 ± 3.9）% and （13.8 ± 1.4）%, and the apoptotic rate was （3.30 ± 0.70）%. In the negative control group, the proportion of cells in p
