Abstract
The incidence of gastric cancer is very high in Japan, Korea, and China. Reducing the morbidity and mortality associated with gastric cancer requires early diagnosis, which can be facilitated by applying gastroscopy more frequently in high-risk groups. A strategy of population screening for gastric cancer is currently being adopted in Korea, Japan, and the Matsu region of Taiwan, but using different screening methods. In addition, the history of pepsinogen (PG) in research as a gastric cancer biomarker has varied, in that the use of serum levels of PGI and PGII and the PGI/PGII ratio as gastric cancer screening tools was introduced in Japan before 1990, but in Korea the first research results were only reported in 2008. This review first evaluates the physiology of PG, followed by the usefulness or limitations of serum PG testing with regard to the detection of gastric cancer. Finally, the factors affecting the efficacy of PG tests as a gastric cancer biomarker (i.e., Helicobacter pylori infection status, gender, histopathologic features, and cancer location and depth) are evaluated. It was found that the strategies used to increase the efficacy of PG tests should be individualized in each country according to the seroprevalence of H. pylori.