In the current report, MnSOD WT treatment significantly inhibited cell viability, colony formation, wound healing, and Matrigel transwell invasiveness; blocked cell cycle at G2-phase; induced cell apoptosis in gastric cancer cells; and inhibited SGC7901 xenograft growth (Figure 2, 3, and 4) which was associated with induction of p53 and p21 expression, down-regulation of cyclin D1, and inhibition of EMT (upregulation of E-cadherin and downregulation of N-cadherin) (Figure 5). This evidence concerns the gene CCND1 and gastric cancer.