CCND1 and gastric cancer: In the current study, our findings showed that miR-9-mediated inhibition on cell cycle progression and cell proliferation was rescued by restoration of cyclin D1 expression in gastric cancer cells, suggesting that the identification of cyclin D1 as a miR-9 target gene, may explain, at least in part, why over-expression of miR-9 suppressed the proliferation of gastric cancer cells.