PDCD4 and hepatocellular carcinoma: To testify this hypothesis, we first examined the expressions of PDCD4 in three human HCC cell lines with different metastasis potentials, then we transfected a plasmid encoding the PDCD4 gene into HCC cells with lowest PDCD4 expression level and further investigated the effects of PDCD4 on the gene expression of MTA1 and migration and invasion of HCC cells.