We therefore conducted this study to explore the expression of AEG-1 mRNA and AEG-1 protein in three RB cell lines and in human RB samples, and then to construct a lentivirus-mediated knockdown of AEG-1 to downregulate its expression in the human retinoblastoma Y79 and SO-RB50 cell lines in vitro. This evidence concerns the gene MTDH and retinoblastoma.