Gastrin is a gastrointestinal hormone secreted by gastric antrum G cells, and its level is mainly affected by the number and function of G cells, as well as by the negative feedback regulation of gastric acid . As a gastrointestinal hormone, G17 can not only maintain the integrity of digestive tract structure, but also regulate the function of digestive tract. Gastrin 17 level can be used as a biomarker to reflect the function and structure of gastric mucosa. Combined with serum PG and G17 levels, it can provide diagnostic information of gastric mucosa, reflect the degree of gastric aging too, and distinguish pathological state from healthy state . G17 also has multiple biological functions of promoting proliferation and inhibiting apoptosis. The changes of serum G17 level can reflect the state of gastric mucosal lesions, so it can be used as a screening index for gastric cancer and precancerous diseases.
PG is the precursor of pepsin, which is mainly secreted by the main cells. PGI, PGII and their ratio are considered as predictors of various gastric diseases, including atrophic gastritis (AG) and intestinal metaplasia (IM), which are defined as precancerous lesions of gastric cancer . One meta-analysis showed that the sensitivity and specificity of PG in the diagnosis of AG were 69% and 88% , while another meta-analysis for joint detection showed that the sensitivity and specificity were 74.7% and 95.6%, which were also higher than that of G17 alone in the diagnosis of AG. In this study, G17 and PG showed a weak to moderate correlation, consistent with Wang Rui`s result , which side confirmed that the combined screening effect of G17 and PG was better.
HP positive is considered as a primary carcinogen. HP infection can induce cell division, increase the probability of cell gene mutation, and play an important role in the occurrence and development of gastric cancer . Studies on Helicobacter pylori infection were carried out in China and South Korea respectively. It was found that in Hp positive patients the serum levels of G-17, PGI and PG II increased, especially PG Ⅱ, while the ratio of PGI/PGII decreased [8, 15]. This study also found that the level of G17 in Hp positive group was significantly higher than that in negative group, which was showing no difference with other studies [16, 17]. Patients with Helicobacter pylori infection and low PGI / PGII ratio should be considered as higher risk of GC and secondary diagnosis (endoscopy and histology) should be performed.
Because G17 is easily affected by many factors, such as lesion location, atrophic degree, HP infection, and even inflammatory indicators, for example, this study found that the risk of abnormal G17 in patients with elevated serum amyloid A increased by 2.692 times, so it is not a major diagnostic indicator, but can be combined with PG and Hp detection as a reference to further improve the diagnosis rate of atrophic gastritis and early gastric cancer, also can directly screen high-risk groups. Arrange endoscopy and histological examination according to the results, enhance the compliance of screening and treatment of gastric diseases, avoid unnecessary radiation and discomfort caused by endoscopic examination.
In recent years, Chinese scholars have been drawing on the overseas screening mode of gastric cancer, combined with the situation of China and the current epidemiological investigation, have successively promoted the "four items gastric function" test combined with gastrin-17, pepsinogen, and Helicobacter pylori. With expectation to find and optimize the screening path of early gastric cancer suitable for China's national conditions, timely provide evaluation and intervention suggestions for high-risk groups, early screening, early diagnosis, early treatment, reduce mortality, prolong life, and protect people's health.