Measuring serum pepsinogen level for screening early stage of gastric cancer / Монголын Анагаах Ухаан

ABSTRACT

@#Gastric cancer is the second leading cause of death worldwide. About half of the incidence of stomach cancer has been reported in East Asian countries. In Mongolia, gastric cancer is the second most common cancer in males and the third most common in females. The age-standardized mortality rate for gastric cancer was 29.3 per 100,000 in 2016, ranking second after liver cancer. Pepsinogen (PG) is a proenzyme of pepsin, by chief and mucous neck cells in the gastric mucosa. On the basis of the source of secretion, PGs are subdivided into 2 types PG I and II. PG I is only secreted from the fundic glands in the corpus of the stomach, whereas PG II is secreted from the corpus, as well as the pyloric glands in the antrum and proximal duodenum. PG is excreted mainly into the stomach lumen, but approximately 1% diffuses into the blood stream. Atrophic gastritis and intestinal metaplasia are well-known risk factors for gastric neoplasms including dysplasia. To identify these premalignant gastric conditions, histological biopsy or image-enhanced endoscopy is performed. Gastric cancer is usually preceded by a decades-long precancerous process driven by Helicobacter pylori infection and environmental conditions with well-defined successive lesions. In the advanced stages, they are characterized by glandular atrophy and intestinal metaplasia. These changes involve loss of the original glands and result in decrease of the mass of chief cells of the gastric corpus, where PGI is produced. Loss of chief cells leads to lower PGI levels and PGI/PGII ratio in the peripheral blood. Serum PG levels are therefore a key tool to be used in screening programs. Serum PG measurements could provide a simple and noninvasive method for screening gastric neoplasms.