Simvastatin, a cholesterol-lowering drug, can sensitize the gastric cancer to the antitumor effects of capecitabine through suppressing the constitutive activation of NF-κB and expression of COX-2, cyclin D1, Bcl-2, survivin, CXC motif receptor 4, and MMP-9 proteins in gastric cancer cells. The gene discussed is MMP9; the disease is gastric cancer.