To investigate the effects of CXCR4 silencing on tumor metastasis, both migration and invasion assays showed that migratory and invasive abilities were significantly decreased in PC9/CXCR4-shRNA1 and PC14/CXCR4-shRNA1 cells compared to the control cells (P < 0.001) (Fig. 1B and C; Fig. S3B and C). Here, CXCR4 is linked to neoplasm.