Correlation of Epstein-Barr virus and its encoded proteins with Helicobacter pylori and expression of c-met and c-myc in gastric carcinoma

AIM： To investigate the interrelationship of Epstein-Barr virus （EBV） and EBV- encoded proteins with Helicobacter pylori （H pylor/~ infection and the expression of c-met and c-myc oncogene proteins in gastric carcinoma, and to explore their role in gastric carcinogenesis. METHODS： One hundred and eighty-five gastric carcinoma tissues were detected by polymerase chain reaction （PCR）-Southern blot for EBV genome and in situ hybridization （ISH） for EBV-encoded small RNA 1 （EBER1）. Gastric carcinoma with positive EBER1 signals was confirmed EBV-associated gastric carcinoma （EBVaGC）. The status of Hpylori infection in 185 gastric carcinomas was assessed by rapid urease test and PCR. The samples with positive PCR and urease test were defined as H pylorl infection. The expression of c-met and c-myc oncogene proteins in tissues of EBVaGC and matched EBV-negative gastric carcinoma （EBVnGC） were examined by immunohistochemistry. RT-PCR and Southern hybridization were used to detect the expression of nuclear antigens （EBNAs） 1 and 2, latent membrane protein （LMP） 1, early genes BARF1 and BHRF1 in EBVaGC cases. RESULTS： The positive rate of H pylori and EBV in 185 gastric carcinomas was 59.45% （110/185） and 7.03% （13/185） respectively. No difference was found in sex, age, pathological differentiation, clinical stages and lymph node metastasis between H pylori-positive and H pylori-negative gastric carcinomas. However, the positive rate of H pylori infection in the antrum gastric carcinomas was higher than that of cardia and body gastric carcinomas. In our series, age, pathological differentiation, clinical stages, lymph node metastasis and location of cancer were not different between EBVnGC and EBVaGC, while the positive rate of EBV in male patients was significantly higher than that of female patients. The positivity of Hpylori in EBV-associated and EBV-negative gastric carcinomas was 46.15% （6/13） and 81.40%（104/172） respectively. There was no significant correlation between EBV and H pylori infection. The c-met overexpression was significantly higher in the EBVaGC group than in the EBVnGC group. However, c-met and c-myc expression did not show significant difference between the two groups. Transcripts of EBNA1 were detected in all 13 EBVaGCs, while both EBNA2 and LMP1 mRNA were not detected. Six of the 13 cases exhibited BARF1 transcripts and 2 exhibited BHRF1 transcripts. CONCLUSION： The positivity of H pylori in EBVnGCs is higher than that of EBVaGCs, but no significant correlation is found between EBV infection and H pylori infection. H pylori-positive gastric carcinoma is predominant in antrum location, while EBVaGC has a tendency of predominance in cardia/body location. EBV infection is associated with c-met abnormal expression but not with c-myc protein in EBVaGC. c-met overexpression is not induced by LMP1. BARF1 and BHRF1 may play important roles in the tumorigenesis of EBVaGC through different pathways.

Helicobacter pylori Infection Facilitates the Expression of Resistin-like Molecule Beta in Gastric Carcinoma and Precursor Lesions

Helicobacter pylori(H.pylori)was reported to be associated with gastric carcinogenesis.Resistin-like molecule beta(RELMβ),a recently described goblet cell-specific protein,was demonstrated to aberrantly express in gastric cancer and correlated with its clinicopathological features.This study aimed to examine the association between H.pylori and RELMp expression in gastric carcinoma and precursor lesions.H.pylori infection and RELMβexpression were immunohistochemically evaluated in gastric biopsies from 230 patients.The biopsies consisted of normal gastric mucosa(w=20),mucosa with chronic gastritis(n=41),intestinal metaplasia(n=42),dysplasia(w=31),intestinal-type adenocarcinoma(n=56),and diffuse-type adenocarcinoma(n=40).RELMβ expression was measured in gastric biopsies after H.pylori eradication therapy in a subgroup of 32 patients.Cultured gastric cancer cell line SGC-7901 was infected with H.pylori strains,and RELMp expression was detected by reverse transcription PCR,real-time PCR and Western blotting.Higher RELMP immunoreactivity was observed in H.pyloripositive intestinal metaplasia(P=0.003),dysplasia(P=0.032),intestinal-type(P=0.037)and diffuse-type adenocarcinomas(P=0.001)than in H.pylori-negative specimens.Expression rates of RELMβ in dysplasia(CO.005),intestinal-type adenocarcinoma(P<0.001),and diffuse-type adenocarcinoma(P=0.001)were significantly correlated with the grade of H.pylori density.In addition,H.pylori eradication reduced the RELMβintensity in intestinal metaplasia(P=0.001).Infection of gastric cancer SGC-7901 cells with cag pathogenicity island(PAI)-positive H.pylori TN2,but not with its PAI totally deleted mutant(TN2-APAI)for 4-8 h,resulted in enhanced protein and transcript levels of RELMβ(P<0.05).In summary,our study suggested that H.pylori infection facilitated the expression of RELMβ in gastric garcinoma and precursor lesions.

Helicobacter pylori infection and gastric carcinoma:Not all the strains and patients are alike

Gastric carcinoma(GC) develops in only 1%-3% of Helicobacter pylori(H. pylori) infected people. The role in GC formation of the bacterial genotypes, gene polymorphisms and host's factors may therefore be important. The risk of GC is enhanced when individuals are infected by strains expressing the oncoprotein CagA, in particular if CagA has a high number of repeats containing the EPIYA sequence in its C'-terminal variable region or particular amino acid sequences flank the EPIYA motifs. H. pylori infection triggers an inflammatory response characterised by an increased secretion of some chemokines by immunocytes and colonised gastric epithelial cells; these molecules are especially constituted by proteins composing the interleukin-1beta(IL-1β) group and tumour necrosis factor-alpha(TNF-α). Polymorphisms in the promoter regions of genes encoding these molecules, could account for high concentrations of IL-1β and TNF-α in the gastric mucosa, which may cause hypochlorhydria and eventually GC. Inconsistent results have been attained with other haplotypes of inflammatory and anti-inflammatory cytokines. Genomic mechanisms of GC development are mainly based on chromosomal or microsatellite instability(MSI) and deregulation of signalling transduction pathways. H. pylori infection may induce DNA instability and breaks of double-strand DNA in gastric mucocytes. Different H. pylori strains seem to differently increase the risk of cancer development run by the host. Certain H. pylori genotypes(such as the cagA positive) induce high degrees of chronic inflammation and determine an increase of mutagenesis rate, oxidative-stress, mismatch repair mechanisms, down-regulation of base excision and genetic instability, as well as generation of reactive oxygen species that modulate apoptosis; these phenomena may end to trigger or concur to GC development.

Trisomy 3 may predict a poor response of gastric MALT lymphoma to Helicobacter pylori eradication therapy

AIM: To investigate the relation of the response to Helicobacter pylori eradication therapy to the depth of tumor invasion and chromosome abnormalities in patients with mucosaassociated lymphoid tissue (MALT) lymphoma and to determine the clinical value of aneuploidy.METHODS: We studied 13 patients with localized gastric MALT lymphoma of stage E1. Before eradication therapy,the depth of tumor invasion was assessed by endoscopic ultrasonography in 8 patients and by endoscopic examination and gastrointestinal series in the remaining patients. To detect chromosomal abnormalities, paraffin-embedded tissue sections of diagnostic biopsy specimens underwent tissuefluorescence in situ hybridization (FISH), using chromosomespecific α-satellite DNA probes for chromosomes 3,7,12,and 18 and YAC clones for t(11;18)(q21;q21).RESULTS: Seven of the 13 patients had complete regression(CR) in response to H pylori eradication therapy. No patient with CR had submucosal tumor invasion. Trisomy 18 was seen in 1 patient with CR, and both trisomies 12 and 18 were present in another patient with CR. All patients with no response or progressive disease had deep submucosal tumor invasion and showed t(11;18)(q21;q21) or trisomy 3. Trisomy 7 was not detected in this series of patients.CONCLUSION: The depth of tumor invasion is an accurate predictor of the response of stage E1 MALT lymphoma to H pylori eradication therapy and is closely associated with the presence of chromosomal abnormalities. Trisomy 3 may predict the aggressive development of MALT lymphoma.

Dickkopf-related protein 1/cytoskeleton-associated protein 4 signaling activation by Helicobacter pylori-induced activator protein-1 promotes gastric tumorigenesis via the PI3K/AKT/mTOR pathway

BACKGROUND Gastric cancer(GC)is a common malignant tumor with high incidence and mortality rates globally,especially in East Asian countries.Helicobacter pylori(H.pylori)infection is a significant and independent risk factor for GC.However,its underlying mechanism of action is not fully understood.Dickkopf-related protein(DKK)1 is a Wnt signaling antagonist,and cytoskeleton-associated protein(CKAP)4 is a newly identified DKK1 receptor.Recent studies found that the binding of DKK1 to CAKP4 mediated the procancer signaling of DKK1 independent of Wnt signaling.We hypothesize that H.pylori-induced activation of DKK1/CKAP4 signaling contributes to the initiation and progression of GC.AIM To investigate the interaction of H.pylori infection,DKK1 and CAKP4 in GC,as well as the underlying molecular mechanisms.METHODS RNA sequencing was used to identify differentially expressed genes(DEGs)between H.pylori-infected and uninfected primary GC cells.Gain-and loss-offunction experiments were performed to verify the H.pylori-induced upregulation of activator protein-1(AP-1)in GC cells.A dual-luciferase reporter assay and co-immunoprecipitation were used to determine the binding of AP-1 to the DKK1 promoter and DKK1 to CKAP4.Western blotting and immunohistochemistry detected the expression of DKK1,CKAP4,and phosphatidylinositol 3-kinase(PI3K)pathway-related proteins in GC cells and tissues.Functional experiments and tumorigenicity in nude mice detected malignant behavior of GC cells in vitro and in vivo.RESULTS We identified 32 DEGs between primary GC cells with and without H.pylori infection,including JUN,fos-like antigen-1(FOSL1),and DKK1,and confirmed that the three proteins and CKAP4 were highly expressed in H.pylori-infected GC cells,H.pylori-infected gerbil gastric tissues,and human GC tissues.JUN and FOSL1 form AP-1 to transcriptionally activate DKK1 expression by binding to the DKK1 promoter.Activated DKK1 bound to CKAP4,but not the most common Wnt coreceptor low-density lipoprotein receptor-related protein 5/6,to promote GC cell growth,colony formation,migration,invasion,and xenograft tumor growth in nude mice.All these effects were driven by activation of the PI3K/AKT/mammalian target of rapamycin(mTOR)pathway.Targeting the PI3K signaling pathway by LY294002 inhibited DKK1-mediated CKAP4/PI3K signaling activity and the malignant behavior of GC cells.CONCLUSION H.pylori induces JUN and FOSL1 expression to form AP-1,which transcriptionally activates DKK1.Binding of DKK1 to KAKP4 contributes to gastric tumorigenesis via the PI3K/AKT/mTOR pathway.

Effect of Jianpi Jiedu Recipe on angiogenesis and the PTEN/PI3K/AKT signaling pathway in the course of Helicobacter pylori-induced gastric cancer in C57BL/6 mice

Objective： To reveal the effect of Jianpi Jiedu recipe （JPJDR） on angiogenesis and the PTEN （Phosphatase and tensinhomolog deleted on chromosome ten）/PI3K/AKT signaling pathway in the course of H. pylori infection-inducedcarcinogenesis of gastric mucosa in C57BL/6 mice. Methods： Two-hundred C57BL/6 mice were randomly divided intofive groups （control group, model group, JPJDR low-dose group, JPJDR medium-dose group, and JPJDR high-dosegroup）, 40 in each group. A mouse model of gastric cancer, induced by H. pylori standard strain infection, wasestablished. The mice of JPJDR low-dose, middle-dose, and high-dose groups were intragastrically administered 250,500, and 1000 mg/kg JPJDR per day, respectively. After 72 weeks, the H. pylori infection in gastric mucosa of the micewas analyzed by rapid urease test; the pathological changes in the gastric mucosa of mice were assessed byhistopathological examination, and micro-vessel density （MVD）, vascular endothelial growth factor （VEGF）, andPTEN/PI3K/AKT levels were determined. Results： The incidence of gastric cancer in each group （control group, modelgroup, JPJDR low-dose, medium-dose, high-dose group） was 0%, 26.3%, 13.2%, 10%, and 7.5% respectively. Theincidence of gastric cancer in the Chinese medicine group was significantly lower than that of the model group （P =0.020, P = 0.023, P = 0.007）. The expression of MVD and VEGF in the model group was significantly higher than thatin the control group （P = 0.002, P 〈 0.001）, while the expression of MVD and VEGF decreased in the Chinese medicinegroup. The expression of p-PTEN and p-AKT in the model group was significantly higher than that in the control group（All P 〈 0.001）, while Chinese medicine could reduce the expression of p-PTEN and p-AKT to varying extents.Conclusion： Long-term infection of C57BL/6 mice with H. pylori induces gastric carcinogenesis, by increasing gastricmucosal MVD, promoting the expression of VEGF, inhibiting the activity of PTEN, and activating the PI3K/AKTsignaling pathway. JPJDR can reduce the infection rate of H. pylori in mouse gastric mucosa, inhibit the expression ofMVD and VEGF, and reduce the inactivation of PTEN.

Comparative genomic study of gastric epithelial cells co-cultured with Helicobacter pylori

AIM:To identify genes potentially involved in Helicobacter pylori(H.pylori)-induced gastric carcinogenesis.METHODS:GES-1 cells were co-cultured with H.pylori strains isolated from patients with gastric carcinoma(GC,n = 10) or chronic gastritis(CG,n = 10) for in vitro proliferation and apoptosis assays to identify the most and least virulent strains.These two strains were cagA-genotyped and used for further in vivo carcinogenic virulence assays by infecting Mongolian gerbils for 52 wk,respectively;a broth free of H.pylori was lavaged as control.Genomic profiles of GES-1 cells cocultured with the most and least virulent strains were determined by microarray analysis.The most differentially expressed genes were further verified using quantitative real-time polymerase chain reaction in GES-1cells infected with the most and least virulent strains,and by immunohistochemistry in H.pylori positive CG,precancerous diseases,and GC biopsy specimens in an independent experiment.RESULTS:GC-derived H.pylori strains induced a potent proliferative effect in GES-1 cells in co-culture,whereas CG-derived strains did not.The most(from a GC patient) and least(from a CG patient) virulent strains were cagA-positive and negative,respectively.At week 52,CG,atrophy,metaplasia,dysplasia,and GC were observed in 90.0%,80.0%,80.0%,90%,and 60.0%,respectively,of the animals lavaged with the most virulent strain.However,only mild CG was observed in 90% of the animals lavaged with the least virulent strain.On microarray analysis,800 differentially expressed genes(49 up-and 751 down-regulated),involving those associated with cell cycle regulation,cell apoptosis,cytoskeleton,immune response,and substance and energy metabolisms,were identified in cells co-cultured with the most virulent strain as compared with those co-cultured with the least virulent strain.The six most differentially expressed genes(with a betweenness centrality of 0.1-0.2) were identified among the significant differential gene profile network,including JUN,KRAS,BRCA1,SMAD2,TRAF1,and HDAC6.Quantitative real-time polymerase chain reaction analyses verified that HDAC6 and TRFA1 mRNA expressions were significantly more up-regulated in GES-1 cells cocultured with the most virulent strain than in those cocultured with the least virulent strain.Immunohistochemistry of gastric mucosal specimens from H.pyloripositive patients with CG,intestinal metaplasia(IM),dysplasia,and GC showed that moderately positive and strongly positive HDAC6 expression was detected in 21.7% of CG patients,30.0% of IM patients,54.5% of dysplasia patients,and 77.8% of GC patients(P < 0.001).The up-regulation of TRAF1 expressions was detected in 34.8%,53.3%,72.7%,and 88.9% specimens of CG,IM,dysplasia,and GC,respectively(P < 0.001).CONCLUSION:The overexpression of HDAC6 and TRAF1 in GES-1 cells co-cultured with the GC-derived strain and in H.pylori-positive dysplasia and GC suggests that HDAC6 and TRAF1 may be involved in H.pyloriinduced gastric carcinogenesis.

Evaluation of the relationship between dietary factors,CagA-positive Helicobacter pylori infection,and RUNX3 promoter hypermethylation in gastric cancer tissue

AIM:To evaluate the relationship among Helicobacter pylori(H.pylori) infection,CagA status,and dietary factors with RUNX3 promoter hypermethylation.METHODS:Gastric cancer tissue samples were collected from 184 South Korean patients.All patients were interviewed following a semi-quantitative food frequency questionnaire.The average frequencies of intake and portion sizes of 89 common food items were documented,and total intakes of calories,nutrients,vitamins,and minerals were calculated for each subject.DNA was extracted from gastric cancer tissue samples,and amplification of the HSP60 gene was performed to detect H.pylori infection.Nested polymerase chain reaction(PCR) was used to detect the presence of the CagA gene.RUNX3 gene expression was measured by reverse transcription-PCR,and RUNX3 methylation status was evaluated by methylation-specific PCR.The odds ratios(ORs) and 95%CI associated with RUNX3 promoter hypermethylation status were estimated for each of the food groups,lifestyle factors,and the interaction between dietary and lifestyle factors with CagA status of H.pylori infection.RESULTS:Overall,164 patients(89.1%) were positive for H.pylori DNA,with the CagA gene detected in 59(36%) of these H.pylori-positive samples.In all,106(57.6%) patients with gastric cancer demonstrated CpG island hypermethylation at the RUNX3 promoter.RUNX3 expression was undetectable in 52(43.7%) of the 119 gastric cancer tissues sampled.A high consumption of eggs may increase the risk of RUNX3 methylation in gastric cancer patients,having a mean OR of 2.15(range,1.14-4.08).A significantly increased OR of 4.28(range,1.19-15.49) was observed with a high consumption of nuts in patients with CagA-positive H.pylori infection.High intakes of carbohydrate,vitamin B1,and vitamin E may decrease the risk of RUNX3 methylation in gastric cancer tissue,particularly in CagA-or H.pylori-negative infection,with OR of 0.41(0.19-0.90),0.42(0.20-0.89),and 0.29(0.13-0.62),respectively.A high consumption of fruits may protect against RUNX3 methylation.CONCLUSION:These results suggest that the CagA status of H.pylori infection may be a modifier of dietary effects on RUNX3 methylation in gastric cancer tissue.

Helicobacter pylori-infected animal models are extremely suitable for the investigation of gastric carcinogenesis

Although various animal models have been developed to clarify gastric carcinogenesis, apparent mechanism of gastric cancer was not clarified in recent years. Since the recognition of the pathogenicity of Helocobacter pylori（H pylori）, several animal models with H pylori infection have been developed to confirm the association between Hpylori and gastric cancer. Nonhuman primate and rodent models were suitable for this study. Japanese monkey model revealed atrophic gastritis and p53 mutation after long-term infection of Hpylori. Mongolian gerbil model showed the development of gastric carcinoma with H pylori infection alone, as well as with combination of chemical carcinogens, such as N-methyl- N-nitrosourea and N-methyl-N-nitro-N＇-nitrosoguanidine. The histopathological changes of these animal models after H pylori inoculation are closely similar to those in human beings with Hpylori infection. Eradication therapy attenuated the development of gastric cancer in Hpylori- infected Mongolian gerbil. Although several features of animal models differ from those seen in human beings, these experimental models provide a starting point for further studies to clarify the mechanism of gastric carcinogenesis as a result of Hpylon infection and assist the planning of eradication therapy to prevent gastric carcinoma.

H pylori (CagA) and Epstein-Barr virus infection in gastric carcinomas:Correlation with p53 mutation and c-Myc,Bcl-2 and Bax expression

AIM: To investigate the interrelationship between H pylori and Epstein-Barr virus (EBV) infection in the gastric carcinogenesis having in focus the p53 mutation and the c-Myc, Bcl-2 and Bax expression. METHODS: seventy-one gastric carcinoma tissues were assessed by polymerase chain reaction (PCR) for H pylori and in situ hybridization for EBV. c-Myc, Bcl-2 and Bax expression were detected by immunohistochemistry and single-stranded conformational polymorphism (SSCP) for p53 mutation. RESULTS: The positivity rates for H pylori and EBV were 94.4% and 8.45%, respectively. The majority of the cases displayed only the H pylori presence. All EBV positive cases were also H pylori positive. None infectious agent was observed in 5.55% of the cases. The intestinal type tumor was more frequent in the co-infected and non-infected groups. The female predominated in the non-infected group showing statistical significance (70.4% vs 29.6%, P=0.039). The Bcl-2 was only detected in the group exclusively infected by H pylori. However, c-Myc and Bax were detected in the three groups but with a low frequency in the co-infected group. Mutation of p53 was present in all groups, with the highest frequencies in the H pylori positive groups. CONCLUSION: The frequency of H pylori infection in gastric carcinomas was high. The presented data indicated that gastric carcinogenesis has different pathways depending of the presence of the two investigated infectious agents, suggesting a possible involvement of H pylori with apoptotic process. The low expression of c-Myc and Bax in the EBV-positive groups suggests that EBV may inhibit the expression of these proteins. Nevertheless, p53 mutation shows to be a relevant alteration, independent of both infectious agents.

Analysis of the 3' Variable Region of Cytotoxin-Associated Gene A (<i>cagA</i>) in <i>Helicobacter pylori</i>Isolates in China

Infection by the bacterium Helicobacter pylori is a putative cause of various gastric disorders, including gastric adenocarcinoma. Incident rates are associated with variants of the H. pylori virulence factor cytotoxin-associated gene A protein (CagA), encoded by the gene cagA. However, these variants have not been characterized in China, where gastric cancer is common. We investigated the diversity of CagA variants in H. pylori strains isolated from a Chinese population. The 3' variable region of cagA genes from 66 clinical isolates in China were amplified by polymerase chain reaction, sequenced, aligned, and analyzed. All 66 H. pylori strains were CagA-positive, of which 93.9% were East Asian type and the tyrosine phosphorylation motifs (TPMs) were EPIYA-ABD. The remainder was Western type, in which TPMs were EPIYA-ABC. Interestingly, two of sixty-two strains (3.2%) of the East Asian type were mutated into ESIYA-B, whereas all four Western type (100%) strains were mutated into EPIYT-B. Both of the two strains with Western-type CagA obtained from gastric cancer patients contained a distinguished mutation on the first residue following the EPIYA site in the EPIYA-A motif. The predominant CagA type in these H. pylori strains isolated from Chinese patients in China was East Asian, with TPMs EPIYA-ABD, and there existed mutations in both the East Asian and Western type CagA.

Transcriptomic analysis reveals the promotion of lymph node metastasis by Helicobacter pylori infection via upregulating chemokine (C-X-C motif) receptor 2 expression in gastric carcinoma

Gastric carcinoma (GC) progression is mainly caused by local aggression and lymph node metastasis. However, some patients with early T-stage disease have lymph node metastasis, whereas some patients with late T-stage disease do not have lymph node metastasis, which indicates that invasion and metastasis are not always sequential in some GC patients. In the present study, the data of 101 GC cases were acquired from TCGA and divided into T-late-N-negative and T-early-N-positive groups according to pathological stages. A total of 338 genes were identified as differential genes between the T-late-N-negative and T-early-N-positive groups. GSEA showed that epithelial cell signaling in the Helicobacter pylori (HP ) infection pathway was enriched in the T-early-N-positive group. MB staining indicated that the HP infection rate was 63% (39/62) in N-positive patients compared to 42% (16/38) in N-negative patients. To investigate the potential mechanism, we focused on the gene chemokine (C-X-C motif) receptor 2 (CXCR2), which was not only clustered in the gene set of epithelial cells signaling in the HP infection pathway but also significantly upregulated in T-early-N-positive GC by the analysis of the different genes based on the TCGA dataset. A meta-analysis showed that CXCR2 expression was positively correlated with N-stage but not with T-stage in GC. This study indicated that invasion and metastasis could be independent processes driven by different molecular mechanisms in some GC patients. HP infection was a potential factor that promoted lymph node metastasis by upregulating CXCR2 expression.

Association between Helicobacter pylori seropositivity and digestive tract cancers

AIM： To explore the role of Helicobacter pylori （Hpylori） infection on the risk of digestive tract cancers. METHODS： In total, 199 oral squamous-cell carcinoma （SCC）, 317 esophagea! SCC, 196 gastric cardia and non-cardia adenocarcinoma and 240 colon adenocarcinoma patients were recruited for serum tests of Hpylori infection. Two hospital- and one community-based control groups were used for the comparisons. Hpylori seropositivity was determined by an enzyme linked immunosorbent assay method against Hpylori IgG. RESULTS： Presence of H pylori infection was significantly inversely associated with esophageal SCC [adjusted odds ratio （AOR）： 0.315-0.472, all P-value 〈 0.05] but positively associated with gastric adenocarcinoma （both cardia and non-cardia） （AOR： 1.636-3.060, all P-value 〈 0.05） in comparison to the three control groups. Similar results were not found in cancers of the oral cavity and colon. CONCLUSION： Our findings support the finding that H pylori seropositivity is inversely associated with esophageal SCC risk, but increases the risk of gastric cardia adenocarcinoma.

Revaluation of Helicobacter pylori's role in esophageal carcinoma: A call for comprehensive research

The study by López-Gómez et al,reports a significantly low prevalence(4.5%)of Helicobacter pylori(H.pylori)infection in esophageal cancer patients,contrasting sharply with the general population's infection rate.This finding challenges the established negative association between H.pylori and gastric malignancies,suggesting a potential protective role of H.pylori against esophageal carcinoma,particularly in the context of widespread proton pump inhibitor use.However,the study’s retrospective nature,single-center design,and small sample size limit the generalizability of the findings and raise concerns about selection bias and statistical power.Diagnostic methods primarily based on histology may not detect all cases,especially those with prior antibiotic or proton pump inhibitor use.Additionally,the study does not account for various confounding factors such as dietary habits,socio-economic status,and genetic predispositions that could affect the association between H.pylori and esophageal carcinoma.Further research with larger,more diverse cohorts and comprehensive data collection is necessary to clarify the complex relationship between H.pylori and esophageal carcinoma and substantiate these preliminary findings.

Role of the tumor microenvironment in the pathogenesis of gastric carcinoma

Gastric carcinoma (GC) is the 4th most prevalent cancer and has the 2nd highest cancer-related mortality rate worldwide. Despite the incidence of GC has decreased over the past few decades, it is still a serious health problem. Chronic inflammatory status of the stomach, caused by the infection of Helicobacter pylori (H. pylori) and through the production of inflammatory mediators within the parenchyma is suspected to play an important role in the initiation and progression of GC. In this review, the correlation between chronic inflammation and H. pylori infection as an important factor for the development of GC will be discussed. Major components, including tumor-associated macrophages, lymphocytes, cancer-associated fibroblasts, angiogenic factors, cytokines, and chemokines of GC microenvironment and their mechanism of action on signaling pathways will also be discussed. Increasing our understanding of how the components of the tumor microenviroment interact with GC cells and the signaling pathways involved could help identify new therapeutic and chemopreventive targets.

Methylation of GATA-4 and GATA-5 and development of sporadic gastric carcinomas

AIM:To understand the implication of GATA-4 and GATA-5 methylation in gastric carcinogenesis.METHODS: Methylation status of GATA-4 and GATA-5 CpG islands in human gastric mucosa samples, including normal gastric biopsies from 45 outpatients, gastric dysplasia [low-grade gastric intraepithelial neoplasia (GIN), n = 30; indefinite, n = 77], and 80 paired spo- radic gastric carcinomas (SGC) as well as the adjacent non-neoplastic gastric tissues was analyzed by methylation specific polymerase chain reaction (MSP) and confirmed by denatured high performance liquid chromatography (DHPLC). Immunohistochemical staining was used to detect protein expression. The correlation between GATA-4 and GATA-5 methylation and clinicopathological characteristics of patients including Helicobacter pylori (H. pylori) infection was analyzed.RESULTS:GATA-4 and GATA-5 methylation was frequently observed in SGCs (53.8% and 61.3%, respectively) and their corresponding normal tissues (41.3% and 46.3%) by MSP. The result of MSP was consistent with that of DHPLC. Loss of both GATA-4 and GATA-5 proteins was associated with their methylation in SGCs (P = 0.01). Moreover, a high frequency of GATA-4 and GATA-5 methylation was found in both gastric low-grade GIN (57.1% and 69.0%) and indefinite for dysplasia (42.9% and 46.7%), respectively. However, GATA-4 and GATA-5 methylation was detected only in 4/32 (12.5%) and 3/39 (7.7%) of normal gastric biopsies. GATA-4 methylation in both normal gastric mucosa and low-grade GIN was also significantly associated with H. pylori infection (P=0.023 and 0.027, two-sides).CONCLUSION: Epigenetic inactivation of GATA-4 (and GATA-5) by methylation of CpG islands is an early freuent event during gastric carcinogenesis and is significantly correlated with H. pylori infection.

Abnormal DNA-PKcs and Ku 70/80 expression may promote malignant pathological processes in gastric carcinoma

AIM:To determine the expression of the catalytic subunit of DNA-dependent protein kinase(DNA-PKcs)and the Ku70/Ku80 heterodimer(Ku 70/80)in gastric carcinoma.METHODS:Gastric biopsies were obtained from 146gastric carcinoma patients[Helicobacter pylori(H.pylori)-negative:89 and H.pylori-positive:57]and 34from normal subjects(H.pylori-negative:16 and H.pylori-positive:18)via surgery and endoscopic detection from April 2011 to August 2012 at the First Affiliated Hospital of Nanchang University.Pathological diagnosis and classification were made according to the criteria of the World Health Organization and the updated Sydney system.An‘‘in-house’’rapid urease test and modified Giemsa staining were employed to detect H.pylori infection.The expression of DNA-PKcs and the Ku 70/80protein was detected by immunohistochemistry.RESULTS:Overall,the positive rates of both DNA-PKcs and Ku 70/80 were significantly increased in gastric cancer(χ2=133.04,P<0.001 for DNA-PKcs andχ2=13.06,P<0.01 for Ku)compared with normal gastric mucosa.There was hardly any detectable expression of DNA-PKcs in normal gastric mucosa,and the positive rate of DNA-PKcs protein expression in patients with a normal gastric mucosa was 0%(0/34),whereas the rate in gastric cancer(GC)was 93.8%(137/146).The difference between the two groups was statistically significant.Additionally,the positive rate of Ku 70/80 was79.4%(27/34)in normal gastric mucosa and 96.6%(141/146)in gastric cancer.The DNA-PKcs protein level was significantly increased in gastric cancer(MannWhitney U=39.00,P<0.001),compared with normal gastric mucosa.In addition,there was a significant difference in the expression of Ku 70/80(Mann-Whitney U=1117.00,P<0.001)between gastric cancer and normal gastric mucosa.There was also a significant difference in Ku70/80 protein expression between GC patients with and without H.pylori infection(P<0.05).Spearman analysis showed a negative correlation between tumor differentiation and DNA-PKcs expression(r=-0.447,P<0.05).Moreover,Ku70/80 expression was negatively correlated with both clinical stage(r=-0.189,P<0.05)and H.pylori colonization(r=-0.168,P<0.05).CONCLUSION:Overall,this research demonstrated that enhanced DNA-PKcs and Ku 70/80 expression may be closely associated with gastric carcinoma.

Hp感染与胃癌组织p-STAT3、Bcl-xL、Mcl-1表达的关系及意义

探讨胃癌中Hp感染与p-STAT3、Bcl-xL、Mcl-1蛋白表达的关系及临床意义。结果胃癌组Hp阳性率显著高于正常胃黏膜组(P<0.01);p-STAT3、Bcl-xL、Mcl-1蛋白在胃癌组织中阳性表达率显著高于正常胃黏膜组织(P<0.01),且与胃癌浸润深度、淋巴结转移及临床分期显著相关(P<0.05);Hp感染与p-STAT3蛋白表达呈显著正相关(r=0.401,P<0.01)。Hp感染和STAT3信号通路激活可能共同参与了胃癌的发生发展。

Alteration of sister chromatid exchange frequencies in gastric cancer and chronic atrophic gastritis patients with and without H pylori infection

AIM: To determine, by counting sister chromatid exchange (SCE) frequencies, whether genetic impairment and DNA damage have an effect on the pathogenesis of gastric cancer (GC). METHODS: Analysis of SCE is a cytogenetic technique used to show DNA damage as a result of an exchange of DNA fragments between sister chromatids. We analyzed SCE frequency in 24 patients with GC, 26 patients with chronic atrophic gastritis (CAG), and 15 normal controls. The presence of H pylori was confirmed by urease test, toluidine-blue stain and hematoxylin-eosin stain. RESULTS: SCE was significantly increased in H pylori- negative GC patients, and in H pylori-negative CAG patients compared with controls (7.41 ± 1.36 and 6.92 ± 1.20, respectively, vs 5.54 ± 0.8, P < 0.001). There was no difference in the SCE frequency between H pylori- negative GC patients and H pylori-negative CAG patients (P > 0.05). On other hand, the SCE frequencies in H pylori-positive GC patients were higher than those in H pylori-positive CAG patients (9.20 ± 0.94 vs 7.93 ± 0.81, P < 0.01). Furthermore, H pylori-positive GC patients had a higher SCE frequency than H pylori- negative GC patients (9.20 ± 0.94 vs 7.41 ± 1.36, P < 0.001). Similarly, a significant difference was detected between H pylori-positive CAG patients and H pylori-negative CAG patients (7.93 ± 0.81 vs 6.92 ± 1.20, P < 0.05). CONCLUSION: We suggest the increased SCE in patients reflects a genomic instability that may be operative in gastric carcinogenesis.

Gastric adenocarcinoma of fundic gland type with signet-ring cell carcinoma component: A case report and review of the literature

A depressed lesion was found at a gastric angle of 76-yearold Japanese woman by esophagogastroduodenoscopy. Four years prior, she was diagnosed with a Helicobacter pylori infection but no eradication was performed. The pathological diagnosis of biopsy specimens was signet-ring cell carcinoma. Endoscopic submucosal dissection(ESD) was performed. Histopathological examination of the ESD specimen revealed proliferation of well-differentiated tubular adenocarcinoma mimicking fundic gland cells at the deep layer of the lamina propria mucosae. These tumor cells expressed focally pepsinogen-Ⅰ, diffusely MUC6, and scattered H^+/K^+ ATPase according to immunohistochemistry. Therefore, we diagnosed this tumor as gastric adenocarcinoma of fundic gland type(GA-FG). Adjacent to the GA-FG, proliferation of signet-ring cell carcinoma which diffusely expressed MUC 2 and MUC 5AC was observed. Intestinal metaplasia was focally observed in the surrounding mucosa of the signet-ring cell carcinoma. To the best of our knowledge, this is the first case report of GA-FG with a signet-ring cell carcinoma component. The origin of signet-ring cell carcinoma, i.e., whether it accidentally arose from a non-neoplastic mucosa and coexisted with the GA-FG or dedifferentiated from the GA-FG is unclear at present. We expect the accumulation of similar cases and further analysis to clarify this issue.