MMP9 and retinoblastoma: In the present study, the expression of the MMP-2/MMP-9 gene was downregulated by small hairpin RNA (shRNA) to study its effect on RB cell proliferation, apoptosis, cell cycle, migration, and invasion, and furthermore to explore the potential clinical significance of blocking MMP-2 and MMP-9 gene expression as an antitumor therapeutic target.