Despite the fact that the incidence and mortality of gastric cancer have fallen dramatically over the past several decades it remains a major public health issue as the fifth most common cancer (excluding skin cancer) and the second leading cause of cancer death worldwide. Despite its decreasing trend gastric cancer's incidence, however, continues to be the highest among all cancers in some countries. The epidemiology of gastric cancer has substantial geographical heterogeneity, and its incidence can vary 10-fold between high-risk and low-risk countries. .