Pepsinogen (PG) is a precursor for pepsin, a digestive enzyme specifically produced in the gastric mucosa. Human PG can be classified into two different biochemical and immunological properties, PGI and PGII. Serum PG levels seem to be related to the morphologic and functional changes in the stomach, and used as "serological biopsy." In most Western countries, serum PG testing has been focused on the identification of individuals for intervention studies, whereas in Japan it is used as a part of gastric cancer screening. However, the limited knowledge about serum PG characteristics in Chinese may prejudice the assessment of consistency.
A research article to be published on December 28, 2007 in the World Journal of Gastroenterology (volume 13, issue 48) addresses this question. The research team, led by Prof. Yuan Yuan from China Medical University, spent more than 6 years working with a total of 6990 subjects who underwent large-scale surveys of gastric cancer. The large sample size allowed them to obtain results with high statistical significance and draw very reliable conclusions.
One conclusion reported by the investigators is the essential characteristics of serum PG levels in Chinese are significantly skewed from the normal distribution, and influenced by age, sex, gastric mucosa lesions and H pylori infection. However, thorough investigation is needed for researchers to identify the normal distribution in different age and gender groups by stratification. The investigators suggested these factors, such as being of the male sex, age > 60 years, atrophic lesion and H pylori infection, should be taken into account in the screening of gastric cancer by PG test.
Another conclusion is that PG I/II ratio is better than either PG I or PG II alone in reflecting the development of atrophic lesions on gastric mucosa. Thus, it is can be used for further investigation as a screening tool in the first period.
In this study, the essential characteristics of serum PG in Chinese are described. The results suggest a practical future of serum PG I/II ratio as an effective serological indicator for identifying subgroups with different influence factors. The population-based study reported by Prof. Yuan Yuan is surely of interest to the public and medical professional involved in gastric cancer screening in China.
|Contact: Jing Zhu|
World Journal of Gastroenterology