Transfection of si-CCND1 and si-Ets1 resulted in decreased expression of cyclin D1, pRB, Ets1 and MMP-9 in gastric cancer cells, respectively, when compared to those transfected with scramble siRNA (si-Scb) (Fig. 7A, Fig. 7D and Fig. S5). This evidence concerns the gene MMP9 and gastric cancer.