The role of the HLA-DQA1 gene in resistance to atrophic gastritis and gastric adenocarcinoma induced by Helicobacter pylori infection

Association of HLA gene polymorphisms with Helicobacter pylori related gastric cancer-a systematic review

The appropriate host cell immune responses for the progression of several diseases, including gastric or stomach cancer (GC), are significantly influenced by HLA polymorphisms. Our objective was to systematically review the evidence linking HLA polymorphisms with the risk of Helicobacter. pylori related GC. We conducted a comprehensive literature search to identify studies published between 2000 and April 2023 on the association of HLA polymorphisms with H. pylori related GC using databases such as Medline through PubMed, Embase, Web of Science (core collection), The Cochrane Library, and Scopus. Two authors independently screened articles, extracted data, and assessed the risk of bias using the Risk of Bias Assessment tool for Non-randomized Studies. From 7872 retrieved studies, 19 met inclusion criteria, encompassing 1656 cases and 16,787 controls across four World Health Organization regions, with Japan contributing the most studies. We explored HLA-A/B/C, HLA-DRB1/DQA1/DQB1, HLA-G, and MICA alleles. Of 29 significant HLA polymorphisms identified, 18 showed a positive association with GC, whereas 11 were negatively associated. HLA-DQB1*06 allele was most frequently associated to susceptibility, as reported in four studies, followed by HLA-DRB1*04 and HLA-DQA1*01, each reported in two studies. Conversely, HLA-G*01, HLA-DQA1*01, HLA-DQA1*05, and HLA-DQB1*03 were identified as protective in two studies each. Additionally, five genotypes and six haplotypes were reported as positive, whereas three genotypes and two haplotypes were negative factors for the disease incidence or mortality. Despite heterogeneity in the study population and types of HLA polymorphisms examined, our analysis indicates certain polymorphisms are associated with H. pylori related GC progression and mortality in specific populations.

Occurrence of Helicobacter Pylori in Specimens of Chronic Gastritis and Gastric Adenocarcinoma Patients: A Retrospective Study at University Teaching Hospital, Kigali, Rwanda

Introduction:

Helicobacter pylori (H. pylori) infection is the major cause of gastroduodenal diseases in populations of different ages. We conducted aretrospective studyusing archived tissue samples to determine the prevalence of H. pylori infection among patients diagnosed with gastritis and gastric adenocarcinoma by histopathology cases in one hospital in Rwanda.

Materials and methods:

Cases of chronic gastritis and gastric adenocarcinoma histologically diagnosed in a tertiary hospital in Rwanda over the period of 2016-2018 were studied for the presence of H. pylori using immunohistochemistry. Diagnosis of positive cases considered immunoreactivity as well as bacterial morphology, including spiral, rod-shaped, angulated and coccoid forms.

Results:

Three hundred and seven cases were included in this study; chronic gastritis and gastric adenocarcinoma representing 39% and 61%, respectively. The overall frequency of H. pylori infection was 77.5% (80% among chronic gastritis cases versus 76% among gastric adenocarcinoma cases). Prevalence of H. pylori infection in chronic gastritis and adenocarcinoma did not significantly associate with age and sex.

Conclusion:

The prevalence of H. pylori was high among chronic gastritis and gastric adenocarcinoma cases in Rwanda. Pathologists should investigate the presence of H. pylori in gastric biopsies. Our data shows immunohistochemistry method is feasible and adequate to facilitate detection of H. pylori, which may guide timely treatment.

Chronic atrophic gastritis and intestinal metaplasia surrounding diffuse-type gastric cancer: Are they just bystanders in the process of carcinogenesis?

BACKGROUND

Gastric cancer (GC) is categorized as diffuse- and intestinal-type adenocarcinoma. Intestinal-type GC is associated with chronic gastritis, atrophic gastritis (AG), and intestinal metaplasia (IM), precursors of dysplastic changes. Diffuse-type GC is generally known to undergo de novo carcinogenesis and is not associated with chronic mucosal changes. However, clinically, AG and IM are frequently observed surrounding diffuse-type GC. This study aimed to evaluate the role of AG and IM in diffuse-type GC.

METHODS

We retrospectively reviewed the data of patients undergoing surgery for early GC. We divided patients with diffuse-type GC into two groups according to the presence of AG and IM based on Kyoto classification of gastritis. The clinicopathological characteristics were compared between the groups.

RESULTS

Among patients with diffuse-type GC, 52.5% patients had AG and 18.4% had severe AG. With regard to IM, 42.1% patients had IM and 17.1% had severe IM. Diffuse-type GC combined with severe AG or IM showed larger tumor size and higher submucosal invasion rate than that without severe AG or IM. However, the lymph node metastasis (LNM) rate was not significantly different between the two groups. In multivariate analysis, severe AG or IM was not an independent risk factor for LNM.

CONCLUSIONS

Severe AG or IM surrounding diffuse-type gastric cancer suggests a collapse of normal mucosal barriers and leads to the spread of cancer cells. Although the association between chronic mucosal changes and LNM is unclear, more caution is needed during endoscopy especially for complete resection of diffuse-type GC with these features.

Polymorphisms in HLA-DQ genes, together with age, sex, and Helicobacter pylori infection, as potential biomarkers for the early diagnosis of gastric cancer

BACKGROUND

Polymorphisms in inflammation-related genes are factors associated with the development of gastroduodenal diseases in Helicobacter pylori-infected individuals.

MATERIALS AND METHODS

We aimed to analyze polymorphisms in HLA-DQ, together with other host and H. pylori variables as risk factors for precancerous and cancerous gastric lesions. 1052 individuals were studied, including nonatrophic gastritis (NAG), intestinal metaplasia (IM), gastric cancer (GC) or duodenal ulcer (DU) patients, and healthy volunteers.

RESULTS

Patients with alleles DQA*01:01 (OR 0.78), *01:02 (OR 0.29), *01:03 (OR 0.31), and DQB*02:01/02 (OR 0.40) showed a reduced risk for GC. A multivariate logistic regression analyses showed that patients with homozygote genotypes DQA1*03:01 (OR 7.27) and DQA1*04:01 (OR 8.99) and DQB1*05:01:01 (OR 12.04) were at significantly increased risk for GC. Multivariate analyses also demonstrated that age (OR>10.0) and gender (OR>2.0) were variables that influenced significantly the risk for GC, while H. pylori infection (OR>2.5) increased the risk for IM.

CONCLUSIONS

We identified HLA-DQ alleles associated with IM and GC, and confirm that age, sex, and H. pylori infection are variables that also influence the risk for disease. The use of multiple markers, HLA-DQ alleles, age, sex, and H. pylori infection may be useful biomarkers for the early diagnosis of patients with IM and GC.

Association between HLA-Ⅱgene polymorphism and Helicobacter pylori infection in Asian and European population: A meta-analysis

BACKGROUND

It is generally considered that HLA-Ⅱ genes contribute to the Helicobacter pylori (Hp) infection and disease development process.

AIMS

To perform a meta-analysis to explore the relationship between HLA-Ⅱgene polymorphism and host susceptibility to Hp infection.

METHODS

Relevant cohort studies, case-control studies and cross-sectional studies were identified by searching Cochrane Library, PubMed, EMBASE, Web of Science and CBM up to July 2014. The data were extracted and methodological quality of the studies were evaluated. RevMan5.0 software was used to perform statistical analysis.

RESULTS

In Asian population, HLA-DQB1*0303 acted as the protective gene in Hp infection (statistically significant pooled OR = 0.54) and the susceptible genes in Hp infection involved HLA-DQB1*0401, HLA-DQA1*0103 and HLA-DQA1*0301 (statistically significant pooled OR and 95%CI were 3.34(1.93,5.77), 1.64(1.16,2.33) and 2.03(1.20,3.44) respectively). No statistically significant difference between DQB1*0303, HLA-DQA1*0103 and DQA1*0301 and Hp infection in European population (P>0.05). And no statistically significant difference (P>0.05) in the overall effect of the association between the rest of HLA-Ⅱalleles and Hp infection.

CONCLUSIONS

In Asian population, the protective gene HLA-DQB1*0303 and the susceptible genes HLA-DQB1*0401, HLA-DQA1*0103 and HLA-DQA1*0301 in Hp infection were established by meta-analysis. And there was no HLA-Ⅱallele was found to associate with Hp infection among European population.

Distribution of HLA Tissue Groups in Patients with Gastric Cancer

OBJECTIVE

Gastric cancer is an important disease that is seen all over the world and that threats public health. At the same time, gastric cancer is a heterogeneous disorder with multifactorial etiologies. Recent studies have shown a significant association between HLA antigens and gastric adenocarcinoma. The aim of the present study was to determine the distribution of HLA class I (HLA-A, B and C) and class II (HLA-DR, DQ and DP) antigens in Turkish patients with gastric adenocarcinoma.

MATERIALS AND METHODS

HLA alleles or HLA haplotypes associated with gastric cancer were established in the Turkish population using PSR-SSP analysis in 71 unrelated patients with gastric cancer and in 82 unrelated healthy controls. The statistical significance of differences in allele frequencies between patients and controls was measured by the Chi-square test with Yates's correction.

RESULTS

The study revealed that the HLA-Cw5 antigen is more prevalent in patients with gastric cancer (p=0.042) and that the HLA-DRB1*15 antigen is more prevelent in the control group (p=0.021).

CONCLUSION

It is probable that HLA-Cw5 is a risk factor for gastric cancer whereas HLA-DRB1*15 plays a protective role for this disease. The results show that different loci on HLA may control resistance to or tendency for any disease in different societies; each society should determine its own tissue group.

Host genetic factors respond to pathogenic step-specific virulence factors of Helicobacter pylori in gastric carcinogenesis

The interindividual differences in risk of Helicobacter pylori (H. pylori)-associated gastric cancer involve significant heterogeneities of both host genetics and H. pylori strains. Several recent studies proposed a distinct sequence for H. pylori exerting its virulence in the host stomach: (i) adhering to and colonizing the surface of gastric epithelial cells, (ii) evading and attenuating the host defense, and (iii) invading and damaging the gastric mucosa. This review focuses on several key issues that still need to be clarified, such as which virulence factors of H. pylori are involved in the three pathogenic steps, which host genes respond to the step-specific virulence factors, and whether and/or how the corresponding host genetic variations influence the risk of gastric carcinogenesis. Urease, BabA and SabA in the adhesion-step, PGN and LPS in the immune evasion-step, and CagA, VacA and Tipα in the mucosal damage-step were documented to play an important role in step-specific pathogenicity of H. pylori infection. There is evidence further supporting a role of potentially functional polymorphisms of host genes directly responding to these pathogenic step-specific virulence factors in the susceptibility of gastric carcinogenesis, especially for urease-interacting HLA class II genes, BabA-interacting MUC1, PGN-interacting NOD1, LPS-interacting TLR4, and CagA-interacting PTPN11 and CDH1. With the continuous improvement of understanding the genetic profile of H. pylori-associated gastric carcinogenesis, a person at increased risk for gastric cancer may benefit from several aspects of efforts: (i) prevent H. pylori infection with a vaccine targeting certain step-specific virulence factor; (ii) eradicate H. pylori infection by blocking step-specific psychopathological characteristics of virulence factors; and (iii) adjust host physiological function to resist the carcinogenic role of step-specific virulence factors or interrupt the cellular signal transduction of the interplay between H. pylori and host in each pathogenic step, especially for the subjects with precancerous lesions in the stomach.

Polymorphism in the Helicobacter pylori CagA and VacA toxins and disease

Half of the world's population is infected with Helicobacter pylori and approximately 20% of infected individuals develop overt clinical disease such as ulcers and stomach cancer. Paradoxically, despite its classification as a class I carcinogen, H. pylori has been shown to be protective against development of asthma, allergy, and esophageal disease. Given these conflicting roles for H. pylori, researchers are attempting to define the environmental, host, and pathogen interactions that ultimately result in severe disease in some individuals. From the bacterial perspective, the toxins, CagA and VacA, have each been shown to be polymorphic and to contribute to disease in an allele-dependent manner. Based on the notable advances that have recently been made in the CagA field, herein we review recent studies that have begun to shed light on the role of CagA polymorphism in H. pylori disease. Moreover, we discuss the potential interaction of CagA and VacA as a mediator of gastric disease.

HLA-DP genetic variation, proxies for early life immune modulation and childhood acute lymphoblastic leukemia risk

The human leukocyte antigen (HLA) genes are candidate genetic susceptibility loci for childhood acute lymphoblastic leukemia (ALL). We examined the effect of HLA-DP genetic variation on risk and evaluated its potential interaction with 4 proxies for early immune modulation, including measures of infectious exposures in infancy (presence of older siblings, daycare attendance, ear infections) and breastfeeding. A total of 585 ALL cases and 848 controls were genotyped at the HLA-DPA1 and DPB1 loci. Because of potential heterogeneity in effect by race/ethnicity, we included only non-Hispanic white (47%) and Hispanic (53%) children and considered these 2 groups separately in the analysis. Logistic regression analyses showed an increased risk of ALL associated with HLA-DPB1*01:01 (odds ratio [OR] = 1.43, 95% CI, 1.01-2.04) with no heterogeneity by Hispanic ethnicity (P = .969). Analyses of DPB1 supertypes showed a marked childhood ALL association with DP1, particularly for high-hyperdiploid ALL (OR = 1.83; 95% CI, 1.20-2.78). Evidence of interaction was found between DP1 and older sibling (P = .036), and between DP1 and breastfeeding (P = .094), with both showing statistically significant DP1 associations within the lower exposure categories only. These findings support an immune mechanism in the etiology of childhood ALL involving the HLA-DPB1 gene in the context of an insufficiently modulated immune system.

Helicobacter pylori genotypes can predict gastric tissue histopathology: a longitudinal study of Iranian patients

INTRODUCTION

Several factors have been suggested to account for differences in the virulence of Helicobacter pylori infections in various populations. Evidence suggests the existence of different strains of H. pylori with different degrees of virulence. The present study aimed to investigate the gastric histopathology in Iranian patients infected with H. pylori and to investigate the relationship between the severity of gastritis and four different bacterial virulence-associated genotypes.

METHODS AND MATERIALS

All of the patients with positive results from a pathological examination, a rapid urease test, and PCR analysis for H. pylori infection were consecutively included into the study. The classification and grading of gastritis were performed according to the Sydney System. Esophagitis was classified endoscopically according to the Savary-Miller grading system. The primers used in this study targeted 16S rRNa (521 bp), Urease A (411 bp), Cag A (400 bp), and 26 kDa (303 bp).

RESULTS

Twenty-eight patients were included in the study. The presence of Cag A showed a significant relationship with higher gastritis grades (3.0±0.7 vs. 2.3±0.9, p=0.024) and higher scores for H. pylori infection (3.0±0.7 vs. 2.3±0.7, p=0.027). The patients infected with 26 kDa-positive H. pylori had significantly higher infection scores (3.5±0.6 vs. 2.5±0.6, p=0.020).

CONCLUSION

This study showed that CagA-positive H. pylori infection is associated with more severe gastritis and with increased bacterial density and inflammation in the biopsy specimens. The 303-bp positive genotype was also significantly associated with higher grades of esophagitis. Additional in-depth trials will be helpful in extending our findings.

Association between HLA-DQA1, HLA-DQB1 and oral cancer

Cancer is one of the most common causes of morbidity and mortality. Genes whose products play a critical role in regulation of the immune response include the HLA antigen and cytokine families of genes. Oral cancer is common in men in developing countries, and its frequency is increased by using betel-quid, tobacco, and alcohol. The association between certain HLA Class I and Class II haplotypes and cancer has been documented in a variety of tumors. There was no previous data concerning the association of specific HLA Class II DQA1, DQB1 alleles, or haplotypes with oral cancer patients. In this study, we enrolled 134 Taiwanese patients with histologically confirmed oral cancer and 268 age- and gender-matched healthy Taiwanese adults as control group to investigate the association between HLA-DQA1, HLA-DQB1 allele frequencies and oral cancer patients by using polymerase chain reaction with sequence-specific primers. We found that both HLA-DQA1* and HLA-DQB1* allele frequencies in oral cancer patients revealed no significant difference from those of control groups. Haplotype frequencies of HLA*DQA1-0103-DQB1*0601 in oral cancer patients were significantly lower than those of the control group (odds ratio: 0.18, 95% confidence interval: 0.054-0.583, p(c)=0.02). Our data suggest that HLA DQA1*0103-DQB1*0601 haplotype may be protective with regard to the development of oral cancer.

[Advances in relationship between gastric disease and polymorphisms in both Helicobacter pylori virulence factors and host genetics]

Helicobacter pylori infection may cause many gastric disease, such as peptic ulcers, chronic atrophic gastritis, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. The different clinical outcomes of Helicobacter pylori infection are related to H. pylori virulence factors and host gene polymorphism. H.pylori had been confirmed to be the class I carcinogen by the World Health Organization and International Agency for Research on Cancer Consensus Group (IARC) in1994. Most severe diseases always occur in the background that certain microbial virulence markers (e.g. cagA, vacA) and susceptible host genetic polymorphisms harboured together. Herein, we reviewed the association with H. pylori-related gastric diseases in relation to diffirent H. pylori types and the host polymorphisms.

Factors contributing to the underestimation of Helicobacter pylori-associated gastric cancer risk in a high-prevalence population

OBJECTIVE

This study aimed to identify sources of underestimation of the association between Helicobacter pylori infection and non-cardia gastric cancer, in a high-risk European population.

METHODS

Non-cardia gastric cancer patients (n = 420) recruited in two major hospitals in North of Portugal and population controls (n = 1,389) were evaluated. Whole-cell IgG antibodies against H. pylori were quantified by ELISA and Western Blot testing was conducted in a subsample (272 cases and 186 controls) allowing for the detection of current infection marker and CagA. Sex- and age-adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were computed.

RESULTS

When assessing infection by ELISA, the OR for its association with gastric cancer decreases and reverts as IgG titers increased, from 1.96 (95% CI: 1.09-3.54) for borderline positive results (16.0-21.9 RU/ml) to 0.52 (95% CI: 0.36-0.74) for the highest IgG levels (> or = 102.0 RU/ml). The same pattern was observed across strata of age and blood collection timing with stronger associations among younger subjects and those providing blood samples earlier after diagnosis. The presence of CagA (Western Blot) was associated with an increased risk of gastric cancer (OR = 11.32; 95% CI: 5.64-22.73).

CONCLUSION

The use of methods with low sensitivity to detect past infection leads to a substantial underestimation of gastric cancer risk in high-prevalence settings.

Polymorphisms in TNF and HSP-70 show a significant association with gastric cancer and duodenal ulcer

Tumour Necrosis Factor (TNF) and Heat Shock Protein 70 (HSP70) are important molecules in inflammatory, infectious and tumoral processes. The genes codifying these molecules are polymorphic and certain alleles have been associated with susceptibility to disease. Gastric cancer is associated with an Helicobacter pylori-induced chronic inflammatory response. The aim of this work was to analyze whether polymorphisms in inflammation-related genes are associated with the development of gastric cancer. We studied 447 Mexican adult patients including 228 with non-atrophic gastritis, 98 with intestinal metaplasia, 63 with gastric cancer and 58 with duodenal ulcer, and 132 asymptomatic individuals as well. DNA from peripheral white blood cells was typed for the Single Nucleotide Polymorphisms (SNPs) -308 of TNF-alpha, +252 of TNF-beta, +190 of HSP70-1, +1267 of HSP70-2 and +2437 of HSP70-HOM. Compared with the asymptomatic group, we found a significant association of TNF-beta*A and HSP70-1*C alleles with gastric cancer (OR 5.69 and 3.76, respectively) and HSP70-1*C with duodenal ulcer (OR 3.08). Genotype TNF-beta G/G showed a significant gene-dose effect with gastric cancer (OR 0.09); whereas HSP70-1 C/G showed significant association with both, gastric cancer (OR 13.31) and duodenal ulcer (OR 16.19). Polymorphisms in TNF and HSP70 showed a significant severity-dose-response as risk markers from preneoplastic lesions to gastric cancer in Mexican population, probably because of their association with an intense and sustained inflammatory response.

Synergistic effect of HLA class II loci and cytokine gene polymorphisms on the risk of gastric cancer in Japanese patients with Helicobacter pylori infection

It has been reported that polymorphisms of human leukocyte antigen (HLA) genes and several cytokine genes are associated with an increased risk of developing gastric cancer (GC). However, the results of studies from different geographic regions, ethnic groups and study groups are inconsistent. The aim of this study was to evaluate the influence of H. pylori infection and host genetic factors on GC susceptibility in Japanese patients with GC. We analyzed genotypes for HLA class I and II, tumor necrosis factor alpha, interleukin (IL)-1beta, IL-1 receptor, IL-4, IL-4Ralpha and IL-10 in 330 H. pylori-infected noncardia patients with GC and 190 H. pylori-infected nonulcer dyspeptic controls. Haplotype analyses indicated that the frequencies of the HLA DRB1*0405 and DQB1*0401 alleles were increased in the patients with intestinal-type GC when compared with controls (both DRB1*0405 and DQB1*0401: p = 0.015, OR = 1.57, 95% CI = 1.09-2.26), but the changes were not statistically significant after correction for multiple comparisons. None of the cytokine gene polymorphisms were associated with GC susceptibility, whether patients with GC were analyzed as a group according to the histological subtype. Of interest was the comparison of controls and patients with intestinal-type GC. The frequency of an IL-10-592AA homozygote showing concomitant carriage of the HLA DRB1*0405-DQB1*0401 haplotype was significantly higher in patients with intestinal-type GC (chi(2) = 6.369, p = 0.0116, p(c) = 0.0464, OR = 2.43, 95% CI = 1.21-4.48). Our results suggest that the HLA class II and IL-10-592A/C polymorphisms synergistically affect the susceptibility to GC development of H. pylori-infected individuals in the Japanese population.

Association of the human leukocyte antigen class II alleles with chronic atrophic gastritis and gastric carcinoma in Koreans

OBJECTIVE

Gastric carcinogenesis is a multi-step process and is influenced by several etiological agents, including the host's genetic factors. Since whether a patient remains with chronic superficial gastritis (CSG) or progresses to either chronic atrophic gastritis (CAG) or gastric carcinoma (GC) could be a genetic predisposition unique in each population, we hypothesized that host human leukocyte antigen (HLA) alleles could be discriminative in predicting the risk of CSG progression to precancerous CAG and GC in Koreans.

METHODS

A total of 165 patients with gastric disorders (CSG, 62; CAG, 69 and GC, 34), were selected to investigate the association of HLA class II alleles with the progression of CSG to CAG or GC. HLA genotypes were obtained by the polymerase chain reaction-sequence based typing method.

RESULTS

The phenotypic frequencies of DRB1*1101 and DQA1*0505 were significantly higher in the CAG group compared to those in the CSG group. In the subjects with Helicobacter pylori (H. pypori) (+), the frequencies of DRB1*1501 and DQB1*0602 were significantly lower in the CAG compared to those in the CSG. Further analysis showed that sex (P < 0.05, OR = 0.41-0.42) and age (P < 0.05, OR = 1.05) also affected the risk of progression from CSG to CAG in H. pylori (+) patients carrying the DRB1*1501 or DQB1*0602 allele. Additionally, the frequency of DRB1*0404 in the GC group was significantly higher than that in the gastritis group.

CONCLUSION

Our findings strongly imply an association between HLA class II alleles and the risk of CAG development and GC progression in Koreans.

Gardenia jasminoides Ellis ethanol extract and its constituents reduce the risks of gastritis and reverse gastric lesions in rats

In this study we investigated the effects of Gardenia jasminoides Ellis (GJE) extract and its constituents, such as ursolic acid and genipin, on gastritis in rats and the growth of human gastric cancer cells. The GJE extract, ursolic acid and genipin showed the acid-neutralizing capacities, the antioxidant activities, and the inhibitory effects on the growth of Helicobacter pylori (H. pylori), which are almost equivalent to positive control compounds. In addition, the GJE extract and ursolic acid had cytotoxic activity against AGS and SUN638 gastric cancer cells. The genipin and ursolic acid inhibited significant HCl/ethanol-induced gastric lesions. Taken together, GJE extract and its constituents might have antigastritic activities, associated with the antioxidant activities, acid-neutralizing capacities, and anti-H. pylori action. Also, we could suggest that genipin and ursolic acid may be useful for the treatment and/or protection of gastritis.

Interferon gamma-signature transcript profiling and IL-23 upregulation in response to Helicobacter pylori infection

Helicobacter pylori infection is the major cause of gastroduodenal pathologies including gastric cancer. The long persistence of bacteria and the type of immune and inflammatory response determine the clinical issue. In this study, the global gene expression profile after 6 and 12 months of H. pylori infection was investigated in the mouse stomach, using the Affymetrix GeneChip Mouse Expression Array A430. Genes related to the inflammatory and immune responses were focused. Levels of selected transcripts were confirmed by reverse transcription polymerase chain reaction. Twenty- five and nineteen percent of the differentially expressed genes observed at 6 and 12 months post-infection respectively, were related to immune response. They are characterized by an interferon (IFN)gamma-dependent expression associated to a T helper 1 (Th1) polarised response. In-depth analysis revealed that an up-regulation of IL-23p19, took place in the stomach of H. pylori infected-mice. Strong IL-23p19 levels were also confirmed in gastric biopsies from H. pylori-infected patients with chronic gastritis, as compared to healthy subjects. Our microarray analysis revealed also, a high decrease of H+K+-ATPase transcripts in the presence of the H. pylori infection. Association of gastric Th1 immune response with hypochlorhydria through the down-regulation of H+K+-ATPase contributes to the genesis of lesions upon the H. pylori infection. Our data highlight that the up-regulation of IL-23 and of many IFNgamma signature transcripts occur early on during the host response to H. pylori, and suggest that this type of immune response may promote the severity of the induced gastric lesions.

Association of Helicobacter pylori infection with chronic atrophic gastritis: Meta-analyses according to type of disease definition

Helicobacter pylori is a major risk factor for chronic atrophic gastritis (CAG). A large variety of definitions of CAG have been used in epidemiologic studies in the past. The aim of this work was to systematically review and summarize estimates of the association between H. pylori infection and CAG according to the various definitions of CAG. Articles on the association between H. pylori infection and CAG published until July 2007 were identified. Separate meta-analyses were carried out for studies defining CAG based on gastroscopy with biopsy, serum pepsinogen I (PG I) only, the pepsinogen I/pepsinogen II ratio (PG I/PG II ratio) only, or a combination of PG I and the PG I/PG II ratio. Numbers of identified studies and summary odds ratios (OR) (95% confidence intervals) were as follows: gastroscopy with biopsy: n = 34, OR = 6.4 (4.0-10.1); PG I only: n = 13, OR = 0.9 (0.7-1.2); PG I/PG II ratio: n = 8, OR = 7.2 (3.1-16.8); combination of PG I and the PG I/PG II ratio: n = 20, OR = 5.7 (4.4-7.5). Studies with CAG definitions based on gastroscopy with biopsy or the PG I/PG II ratio (alone or in combination with PG I) yield similarly strong associations of H. pylori with CAG. The association is missed entirely in studies where CAG is defined by PG I only.

Host-bacterial interactions in Helicobacter pylori infection

Helicobacter pylori are spiral-shaped gram-negative bacteria with polar flagella that live near the surface of the human gastric mucosa. They have evolved intricate mechanisms to avoid the bactericidal acid in the gastric lumen and to survive near, to attach to, and to communicate with the human gastric epithelium and host immune system. This interaction sometimes results in severe gastric pathology. H pylori infection is the strongest known risk factor for the development of gastroduodenal ulcers, with infection being present in 60%-80% of gastric and 95% of duodenal ulcers.(1)H pylori is also the first bacterium to be classified as a definite carcinogen by the World Health Organization's International Agency for Research on Cancer because of its epidemiologic relationship to gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue lymphoma.(2) In the last 25 years, since H pylori was first described and cultured, a complete paradigm shift has occurred in our clinical approach to these gastric diseases, and more than 20,000 scientific publications have appeared on the subject. From the medical point of view, H pylori is a formidable pathogen responsible for much morbidity and mortality worldwide. However, H pylori infection occurs in approximately half of the world population, with disease being an exception rather than the rule. Understanding how this organism interacts with its host is essential for formulating an intelligent strategy for dealing with its most important clinical consequences. This review offers an insight into H pylori host-bacterial interactions.

Diet, H pylori infection and gastric cancer: evidence and controversies

Despite decreasing incidence and mortality rates, gastric cancer (GC) still remains the fourth most common cancer and the second most common cause of cancer-related deaths worldwide. Due to the limited treatment options, at present, prevention is likely to be the only effective means of controlling this disease. The success of a prevention strategy depends upon the understanding of etiological and pathogenic mechanisms underlying gastric carcinogenesis. The etiology of GC is multi-factorial, however, in the recent years, mounting evidence suggests that environmental factors play a key role. The most important environmental factors implicated in the pathogenesis of GC are diet and H pylori infection. Thus, modifications in lifestyle and dietary habit associated with eradication of H pylori infection could hypothetically represent the most promising potential targets for GC prevention. In this review we will address the evidence and the controversies on the role of these agents in non-cardia GC by focusing on retrospective and prospective observational studies and interventional trials.

Role of the HLA-DQ locus in the development of chronic gastritis and gastric carcinoma in Mexican patients

AIM: To determine the HLA-DQ locus in Mexican patients with Chronic gastritis and gastric adenocarcinoma.

METHODS: Oligotyping for HLA-DQ locus was performed in 45 Mexican patients with chronic gastritis and 13 Mexican patients with diffuse-type gastric adenocarcinoma, and was then compared with 99 clinically healthy unrelated individuals. H pylori infection and CagA status were assessed in patients by enzyme-linked immunosorbent assay (ELISA) method.

RESULTS: We found a significant increased frequency of HLA-DQB1*0401 allele in H pylori-positive patients with chronic gastritis when compared with healthy subjects [19 vs 0%, P = 1 × 10^-7, odds ratio (OR) = 4.96; 95% confidence interval (95% CI), 3.87-6.35]. We also found a significant increased frequency of HLA-DQB1*0501 in patients with diffuse-type gastric carcinoma in comparison with healthy individuals (P = 1 × 10^-6, OR = 13.07; 95% CI, 2.82-85.14).

CONCLUSION: HLA-DQ locus may play a different role in the development of H pylori-related chronic gastritis and diffuse-type gastric adenocarcinoma in the Mexican Mestizo population.

Helicobacter pylori genotypes in children from a population at high gastric cancer risk: no association with gastroduodenal histopathology

OBJECTIVES

Both bacterial and host determinants underlying differences in histopathology and clinical outcome in H. pylori pediatric infection, as compared to adults, are still poorly documented. Pediatric studies may provide important insights on H. pylori infection immunopathogenesis, particularly in high gastric cancer risk populations. The present study concerns H. pylori genotypic diversity of isolates in children from a population with high gastric cancer risk, and its association with demographic and clinical variables, including gastroduodenal endoscopic and histopathological features.

METHODS

A total of 119 subjects (mean age 10.3 yr, 1.5-18.0 yr) with H. pylori infection were studied. H. pylori vacA, cagA, and iceA genotypes were determined (PCR) in antral-obtained primary cultures; histopathological evaluation was performed in corpus, antrum, and duodenum biopsy specimens.

RESULTS

cagA-, vacA s2m2, and iceA2 were the most prevalent genotypes. No association was observed between H. pylori genotypes and subject demographic and clinical variables, with the exception of a significant association between vacA s2 genotype and lower corpus inflammation score (p< 0.03).

CONCLUSIONS

In this pediatric cohort, H. pylori genotype profiles were distinct from those reported in adult subjects in the same area, with a lower prevalence of the putative more virulent genotypes. Moreover, they were not associated with clinical expression of gastroduodenal disease, suggesting the potential role of host and/or environmental factors for the development of clinical disease at a later age.

Identification of Helicobacter pylori and the cagA genotype in gastric biopsies using highly sensitive real-time PCR as a new diagnostic tool

The CagA protein is one of the virulence factors of Helicobacter pylori, and two major subtypes of CagA have been observed, the Western and East Asian type. CagA is injected from the bacteria into gastric epithelial cells, undergoes tyrosine phosphorylation, and binds to Src homology 2 domain-containing protein-tyrosine phosphatase SHP-2. The East Asian type CagA binds to SHP-2 more strongly than the Western type CagA. Here, we tried to distinguish the CagA type by highly sensitive real-time PCR with the objective of establishing a system to detect H. pylori and CagA subtypes from gastric biopsies. We designed primers and probe sets for Western or East Asian-cagA at Western-specific or East Asian-specific sequence regions, respectively, and H. pylori 16S rRNA. We could detect the H. pylori 16S rRNA gene, Western and East Asian-cagA gene from DNA of gastric biopsies. The sensitivity and specificity for H. pylori infection was 100% in this system. In Thai patients, 87.8% (36/41) were cagA-positive; 26.8% (11/41) were Western-cagA positive and 53.7% (22/41) were East Asian-cagA positive, while 7.3% (3/41) reacted with both types of cagA. These results suggest that this real-time PCR system provides a highly sensitive assessment of CagA type as a new diagnostic tool for the pathogenicity of H. pylori infection.

HLA-DQB1 locus and gastric cancer in Helicobacter pylori infection

BACKGROUND AND AIMS

It has been suggested that the incidence of digestive diseases associated with Helicobacter pylori is influenced by the strain diversity of H. pylori, factors involving the host or environment, and the duration of infection. The authors have previously reported that human leukocyte antigen (HLA)-DQB1*0401 plays an important role in the development of atrophic gastritis in H. pylori infected patients. The aim of the present study was to investigate the relationship between HLA-DQB1 genotype and cancer development.

METHODS

HLA-DQB1 genotyping was performed by the PCR-RFLP method on 122 H. pylori-infected non-ulcer dyspepsia (NUD) patients, 53 gastric cancer patients and 28 uninfected controls. To reliably estimate the grade of atrophic gastritis, histological evaluation was performed.

RESULTS

The allele frequency of DQB1*0401 was significantly higher in intestinal type cancer patients compared with age- and sex-matched H. pylori-infected NUD patients. There was no significant difference in the mean atrophic scores of the biopsy samples from the lesser curvature of the mid-corpus between these groups.

CONCLUSIONS

HLA-DQB1*0401 is a useful marker for determining susceptibility to intestinal type gastric cancer.

Familial gastric cancer - aetiology and pathogenesis

Gastric cancer is the second most common cause of cancer death worldwide. It is estimated that 5-10% of gastric cancer cases have a familial association; however, knowledge concerning the genetic predisposition to familial gastric cancer is currently limited. In this chapter we discuss what is known about the aetiology and pathogenesis of both the diffuse and intestinal forms of familial gastric cancer. We focus particularly on hereditary diffuse gastric cancer because the discovery of germ-line E-cadherin mutations in a number of affected families has opened the prospect of identifying gene carriers, with implications for clinical management. The interplay of other conventional risk factors, such as Helicobacter pylori infection, with genetic factors is also discussed. It is hoped that understanding the genetic basis for familial gastric cancer will facilitate the development of clinically useful screening and preventative procedures.

Role of host genes in sporadic gastric cancer

Gastric cancer remains a major health problem particularly in the developing world. Helicobacter pylori (H. pylori) infection is the most recognised aetiological risk factor for this malignancy. The infection causes a chronic gastritis that is the precursor to all the pathophysiological abnormalities characteristic of gastric carcinogenesis. Genetic polymorphisms have emerged in recent years as important determinants of disease susceptibility and severity. In the case of H. pylori-induced gastric cancer, host genetic polymorphisms play an important role both in the precancerous stages and in the transition to cancer. In particular, polymorphic genes of the adaptive and innate immune response are involved in all stages of the neoplastic process. This field is rapidly expanding and many other genetic determinants are currently being defined. The ultimate value of host genetics should be in understanding the pathogenesis of the disease, which would offer a true opportunity to defeat this global killer.

Gastroduodenal disease, Helicobacter pylori, and genetic polymorphisms

Over the past 20 years, there has been marked progress in our understanding of the role of genetic and environmental factors in the etiology of gastroduodenal disease. Helicobacter pylori infection now is recognized to be the most important environmental factor for both noncardia gastric cancer and peptic ulcer disease. The likelihood of the infection resulting in significant disease depends on genetic polymorphisms influencing the virulence of the organism. However, the specific pattern of disease induced by the infection is determined to a great extent by genetic polymorphisms in the host that govern the local gastric immune response elicited. Genetic factors also are important in the treatment of gastroduodenal diseases. Polymorphisms of host CYP2C19 influence the pharmacokinetics and clinical efficacy of proton pump inhibitor therapy.

Major histocompatibility complex class II inhibits fas antigen-mediated gastric mucosal cell apoptosis through actin-dependent inhibition of receptor aggregation

Escape from normal apoptotic controls is thought to be essential for the development of cancer. During Helicobacter pylori infection, the leading cause of gastric cancer, activation of the Fas antigen (Fas Ag) apoptotic pathway is responsible for early atrophy and tissue loss. As disease progresses, metaplastic and dysplastic glands arise which express Fas Ag but are resistant to apoptosis and are believed to be the precursor cells for adenocarcinoma. In this report, we show that one mechanism of acquired Fas resistance is inhibition of receptor aggregation via a major histocompatibility complex class II (MHCII)-mediated, actin-dependent mechanism. For these studies we used the well-described C57BL/6 mouse model of Helicobacter pylori and Helicobacter felis infection. Under normal conditions, Fas Ag is expressed at low levels, and MHCII expression on gastric mucosal cells is negligible. With infection and inflammation, both receptors are upregulated, and 6.1% of gastric mucosal cells express MHCII in combination with Fas Ag. Using the rat gastric mucosal cell line RGM-1 transfected with murine Fas Ag and MHCIIalphabeta chains, we demonstrate that MHCII prevents Fas receptor aggregation and inhibits Fas-mediated signaling through its effects on the actin cytoskeleton. Depolymerization of actin with cytochalasin D allows receptors to aggregate and restores Fas sensitivity. These findings offer one mechanism by which gastric mucosal cells acquire Fas resistance.

Interleukin-1B (IL-1B) polymorphisms and gastric mucosal levels of IL-1beta cytokine in Korean patients with gastric cancer

Interleukin-1B and IL-1 receptor antagonist gene polymorphisms are associated with an increased risk of gastric cancer (GC) in Caucasian populations. However, recent studies could not find any association between IL-1B-511T polymorphism and the risk of GC in Asians. We tested for an association between IL-1 loci polymorphisms with increased gastric mucosal levels of IL-1beta and an increased risk of developing GC in a Korean population. Polymorphisms of IL-1A-889, IL-1B-31, IL-1B-511 and IL-1RN were genotyped in 434 controls and 234 patients with GC. Mucosal IL-1beta cytokine was measured using an ELISA. The frequencies of IL-1A, IL-1B-511, IL-1B-31 and IL-1RN were not statistically different between controls and all patients with GC. After subclassification of GC, only patients with intestinal-type GC showed a higher frequency of IL-1B-31T homozygotes (OR = 2.2; 95% CI = 1.1-4.3) compared with controls. Risk was also significantly increased in these patients for IL-1B-31T homozygotes compared with patients with diffuse-type GC (OR = 3.4; 95% CI = 1.5-7.7). As in Caucasian populations, linkage disequilibrium between IL-1B-31 and IL-1B-511 was nearly complete, but the pattern of haplotype related to the risk of GC (IL-1B-31T/IL-1B-511C) was opposite (IL-1B-511T/IL-1B-31C). Mucosal IL-1beta levels in H. pylori-infected GC patients were higher in patients homozygous for IL-1B-31T compared with IL-1B-31C/T and IL-1B-31C/C. Thus, the combined effects of H. pylori infection and IL-1B-31T/IL-1B-511C polymorphisms with enhanced mucosal IL-1beta production contributed to the development of intestinal-type GC in this Korean population.

Association of Helicobacter pylori-related distal gastric cancer with the HLA class II gene DQB10602 and cagA strains in a southern European population

BACKGROUND

Distinct human leukocyte antigen (HLA)-DQ genes have been associated with an increased or reduced risk for gastric cancer, but its association with Helicobacter pylori status is controversial. In the present study we evaluated the influence of host HLA DQA1 and DQB1 loci, H. pylori genotype, and socio-economic factors on predicting H. pylori-associated distal gastric cancer in a southern European population.

MATERIAL AND METHODS

In a prospective case-control (1 : 2) study, 42 patients with H. pylori-associated distal gastric cancer were matched by age (+/-5 years) and gender to 84 patients with H. pylori-associated benign gastroduodenal disease (controls). The level of education received, smoking status, alcohol consumption, origin and familial history of gastric cancer were registered at inclusion. HLA DQA1 and DQB1 typing and H. pylori genotyping were determined from endoscopic gastric mucosal biopsies.

RESULTS

Compared with control patients, a positive association with cagA(+) strains (p < .002) and a negative association with vacA-s2 strains (p < .02) was found in patients with distal gastric cancer. At the DQB1 locus, the (*)0602 allele was more frequent in distal gastric cancer than in controls (26.2% vs. 4.8%; p < .005). After correction for multiple comparisons (exact multiple regression analysis) the cagA(+) status and the DQB1(*)0602 allele were associated with an increased distal gastric cancer risk (OR 3.7; 95% CI = 1.33-12.26 and OR 4.82; 95% CI = 1.24-19.83, respectively) whereas the vacA-s2 status was associated with a decreased risk (OR 0.33; 95% CI = 0.10-0.94).

CONCLUSION

Our findings suggest that in the H. pylori-infected southern European population, the cagA genotype and the HLA-DQB1(*)0602 gene confer an increased risk for distal gastric cancer.

HLA polymorphisms are associated with Helicobacter pylori infected gastric cancer in a high risk population, China

Helicobacter pylori is one of the most common bacterial infections associated with an increased risk of gastric cancer, but its association with host factors, particularly polymorphisms of the immune response genes, such as human leukocyte antigen (HLA) genes, is still unclear. To investigate the role of HLA polymorphisms in the risk of gastric cancer among subjects with H. pylori infection, a case-control study involving 52 gastric cancer patients and 139 non-cancer controls was conducted in Linqu County, China, an area with a high incidence of gastric cancer. Polymorphisms of HLA class I and class II alleles were determined by PCR with sequence-specific primers (PCR-SSP). The information about H. pylori infection was obtained from previous records. Among 48 class I and 19 class II HLA alleles detected in this study, two alleles, CW*03 and DRB1*01, were found to be distributed significantly differently between patients and controls [odds ratio(OR)=1.95, 95% confidence interval (CI)=1.13-3.35, P=0.017 and OR=4.39, 95% CI=1.39-13.84, P=0.012, respectively). The OR of gastric cancer risk in individuals carrying CW*03/CW*03 or CW*03/CW*N was 2.06, 95% CI=1.05-4.02, P=0.035, while the OR was 3.49, 95% CI=1.0-12.4, P=0.04 for DRB1*01/DRB1*01 or DRB1*01/DRB1*N carriers. The analysis of the interaction between H. pylori infection and HLA risk genotypes of CW*03 or DRB1*01 revealed that the effect of CW*03 and DRB1*01 genotypes on gastric cancer risk was manifested stronger in H. pylori-positive individuals (OR=5.30, 95% CI=1.73-16.29, P=0.004 and OR=13.38, 95% CI=2.52-70.98, P=0.002, respectively) than in H. pylori-negative ones (OR=1.25, 95% CI=0.25-6.12, P=0.785 and OR=2.26, 95% CI=0.18-28.88, P=0.531, respectively). The combined effect of the two risk HLA genotypes on gastric cancer risk was also analysed. The result showed that the individuals carrying both the CW*03 and DRB1*01 alleles could only be found in cancer patients (5/52), and not in controls (0/139), further suggesting that CW*03 and DRB1*01 are risk alleles advancing the progression of tumorigenesis. These observations demonstrate that host HLA genotypes may play an important role in the risk of gastric cancer, especially among persons with H. pylori infection.

Molecular biology of gastric cancer: Helicobacter infection and gastric adenocarcinoma: bacterial and host factors responsible for altered growth signaling

Gastric cancer remains the second most common cause of cancer-related mortality worldwide. The single most common cause of gastric cancer is chronic infection with the gram-negative microaerophilic spiral bacterium: Helicobacter pylori. Recent advances in this field have identified host factors which predispose to gastric cancer formation via modulation of the host immune response. In addition, recent work has explored bacterial virulence factors which may directly cause tissue damage, and lead to gastric carcinogenesis, as well as factors responsible for enhanced immune response. Environmental factors, long associated with a predilection for gastric cancer, are recognized as modifiers of key growth signalling pathways within the gastric mucosa and as such lead to growth alterations. This review focuses on exploring new advances in our understanding of bacterial factors, host genetic polymorphisms and the interaction between the bacterium and host at the level of the immune response and the regulation of proliferative and apoptotic signal transduction cascades. Modulation of the pivotal balance between cell growth and cell death leads to the formation of gastric adenocarcinoma.

'Serological biopsy' in first-degree relatives of patients with gastric cancer affected by Helicobacter pylori infection

BACKGROUND

Relatives of patients with gastric cancer are at increased risk of developing this disease, especially if they are infected by Helicobacter pylori. Moreover, H. pylori-related atrophic gastritis and hypochlorhydria are well-documented risk factors for noncardia gastric cancer. Serum pepsinogen I (sPGI) and II (sPGII) levels are low in this condition. The aim of our study was to assess by means of a 'Gastropanel' blood test, including sPGI, sPGII, gastrin-17 (G-17) and antibodies anti-H. pylori (IgG-Hp). both functional and morphological features of gastric mucosa in Hp + ve subjects with a family history of gastric cancer.

MATERIALS AND METHODS

Twenty-five Hp + ve subjects consecutively referred to our department for gastrointestinal complaints, selected as first-degree relatives of patients suffering from gastric cancer, were enrolled in the study and then matched for sex and age with 25 dyspeptic and Hp + ve subjects with no family history of gastric neoplasia. Blood samples were taken for determination of gastropanel in all patients; in addition, antibodies against CagA were analysed.

RESULTS

No statistically significant differences were detected between the two groups as regards alcohol consumption, coffee intake and smoking habits. Mean sPGI levels in Group A (83.4 +/- 58.4 microg/L) were significantly lower than those in Group B (sPGI 159.5 +/- 80.6 microg/L; P < 0.0001) as well as sPGII (12.5 microg/L = 6.24 versus 20.6 +/- 58 microg/L; P < 0.006). No statistical difference was found between the two groups in relation to G-17 levels, IgG-Hp titres and antibodies against CagA.

CONCLUSION

First-degree relatives of patients with noncardia gastric cancer affected by H. pylori infection present lower sPGI and sPGII levels, possibly due to the increased frequency of atrophic lesions in these patients.

Human leukocyte antigen class II genes and Helicobacter pylori infection: does genotype overwhelm environmental exposure?

OBJECTIVE

We investigated associations between human leukocyte antigen class II genes, environmental exposures, and Helicobacter pylori infection.

METHODS

Sixty-eight subjects with histologically confirmed H. pylori and intestinal metaplasia (cases) and 70 healthy subjects without H. pylori (controls) matched for age, sex, and year of birth were included in this study. All patients answered a detailed questionnaire designed to collect sociodemographic characteristics, smoking, alcohol drinking, and dietary habits. Human leukocyte antigen class II genes were typed with genomic DNA. The cytotoxins CagA and VacA were investigated with serology. Odds ratios and corresponding 95% confidence intervals were estimated from multivariate conditional logistic regression. Multiple correspondence analysis was used to represent the interrelationships of a multiple contingency table.

RESULTS

Human leukocyte antigen DRB1, DQA1, and DQB1 genotypes were not significantly associated with H. pylori infection and intestinal metaplasia. No significant association with blood group or Lewis antigen system was found. However, multiple correspondence analysis clearly associated H. pylori with environmental exposure: the control group largely consumed olive oil, fresh fruits, and vegetables and histories of never or formerly smoking and the case group (those positive for H. pylori and metaplasia) largely consumed eggs, meat and butter and had histories of smoking cigarettes.

CONCLUSIONS

These findings suggested that H. pylori infection is not influenced by a genetic compound and confirmed the relevance of environmental exposure.

A coordinated cytotoxic effect of IFN-gamma and cross-reactive antibodies in the pathogenesis of Helicobacter pylori gastritis

BACKGROUND

Helicobacter pylori (H. pylori) infection is associated with chronic infiltration into the stomach by T cells and plasma cells producing IFN-gamma and antibodies of various specificities, respectively. It is unknown whether these lymphocyte-products may play coordinated roles in the gastric pathology of this infection.

AIMS

To know how IFN-gamma may relate to anti-H. pylori antibodies in their roles in pathogenesis, we determined the isotype subclass of those antibodies as well as their cross-reactivity and cytotoxicity to gastric epithelium.

METHODS AND RESULTS

We infected BALB/c mice with H. pylori (SS1, Sydney Strain 1) and generated monoclonal antibodies, which were comprised of 240 independent clones secreting immunoglobulin and included 80 clones reactive to SS1. Ninety percent of the SS1-reactive clones had IgG2a isotype. Two clones, 2B10 and 1A9, were cross reactive to cell surface antigens in H. pylori and to antigens of 28 KDa and 42 KDa, respectively, which were present on the cell surface of and shared by both mouse and human gastric epithelial cells. The antigens recognized by these monoclonal antibodies localized a distinctive area in the gastric glands. In the presence of complement, 2B10 showed cytotoxicity to gastric epithelial cells. The effect was dose dependant and augmented by IFN-gamma. Finally, administration of 2B10 to mice with SS1 infection aggravated gastritis by increasing cellular infiltration.

CONCLUSION

IFN-gamma by gastric T cells may participate in pathogenesis of the H. pylori infected stomach by directing an isotype-switch of anti-H. pylori antibodies to complement-binding subclass and by augmenting cytotoxic activity of a certain autoantibody. This may explain a host-dependent diversity in gastric pathology of the patients with H. pylori infection.

Is there a link between environmental factors and a genetic predisposition to cancer? A lesson from a familial cluster of gastric cancers

To determine the prevalence of gastric precancerous lesions and mucosal genetic alterations in relatives of a cluster of familial gastric cancer (FGC), we studied a kindred spanning two generations. The founder, daughter and niece underwent surgery for gastric cancer (GC); a son and other two daughters of the founder, presented with chronic dyspepsia. In all subjects, gastric mucosa samples were analysed for pathological features, Helicobacter pylori infection, microsatellite (MIN) and chromosomal (CIN) instability. The overexpression of mp53 and c-myc, and cytoplasmic beta-catenin delocalisation were found in the 2 younger cancer patients. All GC and gastritis patients had normal E-cadherin expression and were MIN-negative. Aneuploidy characterised all GC cases, and mixed euploid and aneuploid cell populations were present in the gastric biopsies from two of three 'at-risk' relatives. These two subjects, one of whom had severe active gastritis, and gastric mp53 and c-myc expression, were CagA-positive H. pylori-infected. DNA aneuploidy, p53 and c-myc expression disappeared after H. pylori eradication. In this FGC cluster, genetic abnormalities were found in first-degree relatives (3 patients) only in presence of H. pylori infection (2 cases H. pylori-positive versus 1 case H. pylori-negative) supporting the hypothesis that, besides the influence of a genetic profile, FGC may be, at least partly, mediated by intrafamilial clustering of H. pylori infection.

Review article: test and treat or test and scope for Helicobacter pylori infection. Any change in gastric cancer prevention?

A 'test and treat' strategy is advocated for patients with dyspepsia under the age of 45 years, with endoscopy reserved for those with alarm symptoms or aged over 45 years. One of the consequences of this strategy will be a reduction in population infection rates of Helicobacter pylori. It is now clear that H. pylori is one of the prime initiators of gastric cancer with up to 70% of gastric cancers attributable to H. pylori. What remains unclear is if H. pylori reduction will lead to a reduction in gastric cancer.

Review article: molecular basis of gastric carcinogenesis

Gastric cancer is constituted by two histomorphological entities 'intestinal' and 'diffuse', however lesions with similar morphologies may differ in biological aggressiveness and response to therapy. Two distinct molecular pathways have been identified in gastric carcinogenesis: the microsatellite mutator phenotype and a phenotype associated with chromosomal and intrachromosomal instability. Mounting evidence suggests that microsatellite mutator phenotype alterations and expression of the products of cancer-related genes are early markers of cell transformation, and may serve to identify the gastric carcinoma histotypes. The lack of a clear genetic basis, lends weight to the notion that gastric cancer is not a monomorphic entity but may be affected by environmental factors. Helicobacter pylori is the most important environmental risk factor associated with sporadic gastric cancer. Exposure of gastric epithelial cells to bacterium results in the generation of reactive oxygen species and inducible nitric oxide synthase that in turn may cause genetic alterations leading to cancer in a subset of subjects. Thus, gastric cancer may be considered the result of an interplay between host genetic profile and environmental toxic agents. The new technologies of molecular analysis will help to establish an individual's risk of developing gastric cancer and will lead to novel biological therapeutic strategies.

HLA-DRB1 allele polymorphisms in genetic susceptibility to esophageal carcinoma

AIM: To probe into the genetic susceptibility of HLA-DRB1 alleles to esophageal carcinoma in Han Chinese in Hubei Province.

METHODS: HLA-DRB1 allele polymorphisms were typed by polymerase chain reaction with sequence-specific primers (PCR-SSP) in 42 unrelated patients with esophageal cancer and 136 unrelated normal control subjects and the associated HLA-DRB1 allele was measured by nucleotide sequence analysis with PCR.SAS software was used in statistics.

RESULTS: Allele frequency (AF) of HLA-DRB1*0901 was significantly higher in esophageal carcinoma patients than that in the normal controls (0.2500 vs 0.1397, P = 0.028, the odds ratio 2.053, etiologic fraction 0.1282). After analyzed the allele nucleotide sequence of HLA-DRB1*0901 which approachs to the corresponded exon 2 sequence of the allele in genebank. There was no association between patients and controls in the rested HLA-DRB1 alleles.

CONCLUSION: HLA-DRB1*0901 allele is more common in the patients with esophageal carcinoma than in the healthy controls, which is positively associated with the patients of Hubei Han Chinese. Individuals carrying HLA-DRB1*0901 may be susceptible to esophageal carcinoma.

Family history of gastric cancer: should we test and treat for Helicobacter pylori?

A close link has been established between infection and gastric cancer. In this article, we suggest that using a risk stratification technique (like that for colorectal cancer), the high-risk group of first-degree relatives of patients with gastric cancer can be separated out for testing and treatment. This would be more manageable and more cost-effective than screening the whole population, in which the mortality from distal gastric cancer has declined concomitant with the eradication of infection. Support for the feasibility of this approach is derived from studies showing that the family is the core unit of transmission and that childhood colonization, especially with a virulent strain, is apparently a major risk factor for disease progression to the neoplastic stage. When there is a case of gastric cancer in the family, first-degree relatives, who might be infected by a bacterium with an identical genetic fingerprint, are at higher risk than normal for developing gastric cancer. Furthermore, genetic and epidemiologic studies based on the Correa model have shown that both primary and secondary prevention of gastric cancer is possible. Calculations done in high-risk populations, such as Japanese-Americans, confirm the savings in cost and the safety of the test-and-treat strategy. Considering that eradication should be done as early as possible, at a point in the cascade when the changes are still reversible, and that gastric cancer is associated with a high mortality rate, we suggest that this strategy be applied to this high-risk population.

Helicobacter pylori: resurrection of the cancer link

Helicobacter pylori is one of the most common pathogenic bacterial infections, colonizing an estimated half of all humans. In a subset of individuals, the infection leads to serious gastroduodenal disease such as peptic ulcers and gastric adenocarcinoma. The factors contributing to skewing this, in most cases benign, relationship into disease development are largely unknown. However, factors emanating from the bacterium, host and the environment have been shown to affect the risk for disease, although no factor can be singled out to be most important. The known factors are associated with affecting the risk of disease, and are not absolute. Virulence of H. pylori is affected by the existence and regulation of certain genes present in the bacterial population in a stomach. The effects of H. pylori on gastric cancer development have been challenged and the risk associated with infection with virulent (i.e. Cag PAI positive) H. pylori has likely been underestimated.

Helicobacter pylori infection and gastric cancer: evidence from a retrospective cohort study and nested case-control study in China

AIM: To explore the association between Helicobacter pylori (Hp) infection and risk of gastric cancer in China.

METHODS: Utilizing gastroendoscopic biospsy tissue banks accumulated from1980 to1988 in Shandong, Zhejiang, and Jiangsu, where stomach cancer incidence was high, during stomach cancer screening conducted by Health Science Center of Peking University, School of Medicine of Zhejiang University, and Zhongshan Hospital of Fudan University. Warthin Starry silver staining method was applied to determine H. pylori infection status of biopsies collected during gastroendoscopic examination. In the retrospective study, the subjects were divided into two cohorts, the exposure cohort was positive H. pylori infection, and the non-exposure cohort was negative. Death from stomach cancer was determined as the outcome of the study. Logistic regression and Cox regression were applied to analyze the association between Helicobacter pylori infection and gastric cancer risk. In the nested case-control study, there were 28 deaths from gastric cancer in the fields of Muping, Shandong province, and Zhoushan, Zhejiang provinces. 4 controls were matched to each case on the basis of age ( ± 5 years old), sex, residential place at the same time entered into the study. Conditional logistic regression analysis was used to analyze the data.

RESULTS: There were a total of 2719 subjects (male 1399, female 1320) with gastroendoscopic biopsies stored available treated as a cohort. H. pylori positive cohort included 1671 subjects (61.5%) and H. pylori negative cohort 1048 subjects(38.5%). These subjects were followed up for 1-19 years, averaged 10.88 years. The outcome of death from stomach cancer in the exposure cohort was 33, and in the non-exposure cohort 11. After adjustment for age and sex, RR = 1.9850 (P = 0.0491), 95%CI was 1.0026, and 3.9301. The results of conditional logistic regression showed an OR of 4.467 and 95%CI of 1.161, and 17.190 for the nested case control study.

CONCLUSION: The results from the retrospective cohort study and the nested-case control study on the association of H. pylori infection and gastric cancer in China suggested that Helicobacter pylori infection might increase the risk of stomach cancer.

Role of Helicobacter pylori infection among offspring or siblings of gastric cancer patients

A positive family history is an increased risk factor for gastric cancer within family members, and one of the possible causes of this is the intrafamilial clustering of Helicobacter pylori infection. Our study examined the prevalence of H. pylori infection, serum antibodies to CagA and VacA and atrophic gastritis and/or intestinal metaplasia in the offspring or siblings of gastric cancer patients. A total of 726 subjects included 300 relatives of 300 separate gastric cancer patients and 426 controls. All subjects underwent upper gastrointestinal endoscopic examination with a rapid urease test. Blood samples were obtained to test for the presence of serum antibodies to the CagA and VacA proteins of H. pylori. The prevalence of H. pylori infection was higher in relatives of cancer patients (75.3%) than in controls (60.1%), and the adjusted odds ratio was 2.1 (95% CI 1.5-2.9). When either siblings or 2 or more family members were gastric cancer patients, the prevalence of H. pylori infection was much higher compared to the prevalence in controls. There was no specific relationship between CagA and VacA, and H. pylori infection. Atrophic gastritis and/or intestinal metaplasia were more frequently found in H. pylori-infected relatives of cancer patients (26.1%) than in H. pylori-infected controls (12.9%). These results strongly support a role for H. pylori infection in familial aggregation of gastric cancer. The prophylactic eradication of H. pylori infection in the offspring or siblings of gastric cancer patients may be clinically beneficial.

Synergistic promoting effects of Helicobacter pylori infection and high-salt diet on gastric carcinogenesis in Mongolian gerbils

Helicobacter pylori (Hp) infection and high-salt diet administration are both considered to be important factors in gastric carcinogenesis in man. To investigate the interaction of these two factors on gastric carcinogenesis, an experimental study of the carcinogenesis model was performed. Mongolian gerbils were treated with 20 ppm of N-methyl-N-nitrosourea (MNU) in their drinking water for alternate weeks for a total of 5 weeks' exposure (groups 1, 2, 3 and 4) or were maintained as controls (groups 5, 6, 7 and 8). At week 11, the animals were inoculated with Hp (groups 1, 2, 5 and 6) or the vehicle alone (groups 3, 4, 7 and 8), and after week 12, animals were fed a 10% high salt diet (groups 1, 3, 5 and 7) or the control diet (groups 2, 4, 6 and 8). At week 50, the incidence of adenocarcinomas in group 1 (32.1%, 6 well-differentiated, 2 poorly-differentiated adenocarcinomas, and one signet-ring cell carcinoma) was significantly higher than in groups 3 (0%) (P < 0.005) and 4 (0%) (P < 0.01). The incidence of adenocarcinomas in group 2 (11.8%, one well-differentiated adenocarcinoma, and one signet-ring cell carcinoma) was also higher than in groups 3 and 4. A high-salt diet enhanced the effects of Hp infection on gastric carcinogenesis, and these two factors acted synergistically to promote the development of stomach cancers. Moreover, Hp infection promoted gastric carcinomas more than the high-salt diet.