Knockdown of CXCR4 inhibits the metastasis of PVTT cells in vitro. (A) Western blot results indicate the significant knockdown efficiency of CXCR4 expression. (B) In the transwell culture plate, a cell invasion assay was performed. In the negative control, in which cells were infected with the non-silencing lentivirus, the ratio of invasion was quite high, as shown by Giemsa staining. In the knockdown group, as determined by RNAi methods, the ratio of invasion is decreased by CXCR4 silencing (P < 0.05).