Gastric cancer is a common malignant tumor that originates from the gastric mucosal epithelium. Being insidious and non-specific, the early-stage symptoms of the cancer are similar to that of chronic diseases such as gastritis and gastric ulcer, and are therefore ignored easily. As a result, 80 to 90% of gastric cancer patients have been in the advanced stage when they are first diagnosed. Surgery, with poor prognosis and a 5-year survival rate of only 30%, is still the main treatment for advanced gastric cancer (AGC) at present.