East-Asian-type Of Helicobacter Pylori Infection And The Development Of Gastric Cancer

On a global scale, gastric cancer remains a major killer despite the recentdecline in the incidence of this malignancy. Most of the estimates for gastriccancer incidence treat the cancer as a single entity and it is only recently thatattention has focused on subsite distribution. Proximal gastric cancer causedthe intensive concerns of oncologists because of a significant upwardtendency. What is clear is the fact that Helicobacter pylori (H.pylori) infectionis the most recognized etiological risk factor for gastric cancer and itsprecursors.H.pylori infection induced gastritis called H.pylori correlation gastritis.H.pylori infection causes inflammation and immune response, then induceshyperemia, congestion, edema and neutrophil infiltration in gastric mucous,leading to acute gastric mucosal inflammation, and then develop to chronicgastritis, lymphocytes and plasma cells infiltrated. If the infection lasts for along time, atrophy, intestinal metaplasia and epithelial hyperplasia(intraepithelial neoplasia) appears, resulting in gastric cancer at last.Epidemiological studies show that different strains of H.pylori genepolymorphism has obvious regional distribution difference, and H.pyloriinfection caused by various clinical symptoms, it is mainly because there aresignificant differences between H.pylori genetic features and pathogenic. Thecarcinogenic effects of H.pylori infection have been linked to its virulencefactors, mainly the cag pathogenicity island (cag PAI). Thecytotoxin-associated gene A (cagA) is the main recognized virulence factor ofthe cag PAI. CagA-positive H.pylori strains is associated with high risk ofpeptic ulcers and gastric carcinoma. In East Asian countries, virtually all ofthe H.pylori isolates are cagA-positive, whereas in Western countriesapproximately60%to70%of isolates are cagA-positive. Therefore, H.pylori strains is divided into East-Asian-type (cagA positive) and Western-type(cagA negative) according to the cagA genotype differences,.In recent years, there is an significant upward tendency of proximalgastric cancer incidence in the high risk area of esophageal cancer of Hebeiprovince, while distal gastric cancer incidence is reduced, and the reason forthe variation of the the gastric cancer is not very clear. Up to now, studies onrelationship between H.pylori and gastric cancer were mainly focused ondistal gastric cancer, few study involved in the sub-site of gastric cancer or inthe sub-type of H.pylori. In this study, the infection of H.pylori, especiallyEast-Asian-type H.pylori was detected in three parts and five points of biopsyof stomach (cardia, corpus and antrum). The correlation between H.pyloriinfection and patients who has chronic gastritis, gastric ulcer, gastricintraepithelial neoplasia and gastric cancer were also analyzed to explore therelationship between H.pylori infection, especially East-Asian-type H.pylori,and the development of gastric ulcer and gastric cancer in high risk area ofHebei province.Objective: To explore the relationship between Helicobacter pyloriinfection, especially East-Asian-type H.pylori, and the development of gastriccancer by detecting the expression of both common H.pylori andEast-Asian-type H.pylori in chronic gastritis, gastric ulcer, gastricintraepithelial neoplasia and gastric cancer in high risk area of digestiveneoplasms of Hebei province.Methods:1.351patients were selected, including206cases of chronic gastritis,12cases of gastric ulcer,73cases of intraepithelial neoplasia (low intraepithelialneoplasia24cases, high intraepithelial neoplasia49cases), and60cases ofgastric cancer.2. Different stages of chronic gastritis were classified according to bothupdated Sydney system and visual analog scale, and analyzed by statistics.3. Both common H.pylori antibody called HP and East-Asian-typeantibody called EAS were used in immunohistochemistry, and the expressions of H.pylori in gastric mucosa were detected using HP as a comparison.Results:1. In cardia, corpus and antrum, the positive rate of HP and EAS was62.14%,62.62%,59.71%(P>0.05) and54.37%,53.40%,54.37%(P>0.05)respectively in chronic gastritis; all100.00%in gastric ulcer;100.00%,100.00%,78.57%(P>0.05) and50.00%,50.00%,57.14%(P>0.05) in lowintraepithelial neoplasia (LIN);90.00%,71.43%,83.33%(P>0.05) and36.67%,42.86%,41.67%(P>0.05) respectively in high intraepithelialneoplasia (HIN);80.00%,45.00%,60.00%(P>0.05) and35.00%,25.00%,10.00%(P>0.05) respectively in gastric cancer. No significant differenceswere found in each groups. In the research, East-Asian-type H.pylori infectionshow no relationship with age and gender in adult patients.2. The positive rate of HP and EAS demonstrated statistic significance inchronic gastritis, gastric ulcer, low intraepithelial neoplasia, highintraepithelial neoplasia and gastric cancer. The positive rates were HP:74.76%,100.0%,87.50%,85.71%,61.67%(P<0.05); EAS:66.99%,100.0%,54.17%,38.78%,21.67%(P<0.05); HP(+)EAS(+):89.61%,100.00%,61.90%,45.24%,34.21%(P<0.05).3. The severity of gastritis in this study was analyzed. In cardia, corpusand antrum, statistic significance were found in neutrophils infiltration,mononuclear cells infiltration, atrophy and intestinal metaplasia after usingNonparametric test, and the mean rank was333.41,301.38,293.70(P<0.05);356.25,286.13,286.12(P<0.05);365.69,278.68,284.13(P<0.05);337.14,301.14,290.22(P<0.05) respectively. No significant differences were foundin Hp density, and the mean rank was297.10,324.64,306.76(P>0.05). Themost serious areas of neutrophils infiltration, mononuclear cells infiltration,degree of atrophy, intestinal metaplasia were located in cardia, but Hp densitywas not.4. In cardia, corpus and antrum, positive correlation were demonstratedbetween Hp density and neutrophil infiltration, mononuclear cells infiltration,atrophy degree or intestinal metaplasia by Spearman rank correlation analysis (r>0, P<0.05).Conclusions:1. In high risk area of digestive neoplasms of Hebei province, there wereno differences of East-Asian-type H.pylori infection in cardia, corpus andantrum.2. In cardia, corpus and antrum, positive correlation were found amongHp density and neutrophil infiltration, mononuclear cells infiltration, atrophyor intestinal metaplasia.3. East-Asian-type H.pylori infection may be one of the important riskfactors in the process of cardia cancer.