Preventing Metachronous Gastric Cancer after the Endoscopic Resection of Gastric Epithelial Neoplasia: Roles of Helicobacter pylori Eradication and Aspirin.

Whether Helicobacter pylori eradication actually reduces the risk of metachronous gastric cancer (MGC) development remains a controversial question. In this review, we addressed this topic by reviewing the results of clinical investigations and molecular pathological analyses of the roles of H. pylori eradication and aspirin administration in the prevention of MGC. In regard to the clinical studies, the results of meta-analyses and randomized control trials differ from those of retrospective studies: the former trials show that H. pylori eradication has a preventive effect on MGC, while the latter studies do not. This discrepancy may be at least partly attributable to differences in the follow-up periods: H. pylori eradication is more likely to prevent MGC over a long-term follow-up period (≥5 years) than over a short-term follow-up period. In addition, many studies have shown that aspirin may have an additive effect on MGC-risk reduction after H. pylori eradication has been achieved. Both H. pylori eradication and aspirin use induce molecular alterations in the atrophic gastritis mucosa but not in the intestinal metaplasia. Unfortunately, the molecular pathological analyses of these interventions have been limited by short follow-up periods. Therefore, a long-term prospective cohort is needed to clarify the changes in molecular events caused by these interventions.

Distinguishing potential bacteria-tumor associations from contamination in a secondary data analysis of public cancer genome sequence data.

BACKGROUND: A variety of bacteria are known to influence carcinogenesis. Therefore, we sought to investigate if publicly available whole genome and whole transcriptome sequencing data generated by large public cancer genome efforts, like The Cancer Genome Atlas (TCGA), could be used to identify bacteria associated with cancer. The Burrows-Wheeler aligner (BWA) was used to align a subset of Illumina paired-end sequencing data from TCGA to the human reference genome and all complete bacterial genomes in the RefSeq database in an effort to identify bacterial read pairs from the microbiome. RESULTS: Through careful consideration of all of the bacterial taxa present in the cancer types investigated, their relative abundance, and batch effects, we were able to identify some read pairs from certain taxa as likely resulting from contamination. In particular, the presence of Mycobacterium tuberculosis complex in the ovarian serous cystadenocarcinoma (OV) and glioblastoma multiforme (GBM) samples was correlated with the sequencing center of the samples. Additionally, there was a correlation between the presence of Ralstonia spp. and two specific plates of acute myeloid leukemia (AML) samples. At the end, associations remained between Pseudomonas-like and Acinetobacter-like read pairs in AML, and Pseudomonas-like read pairs in stomach adenocarcinoma (STAD) that could not be explained through batch effects or systematic contamination as seen in other samples. CONCLUSIONS: This approach suggests that it is possible to identify bacteria that may be present in human tumor samples from public genome sequencing data that can be examined further experimentally. More weight should be given to this approach in the future when bacterial associations with diseases are suspected.

Pretreatment antimicrobial susceptibility-guided vs. clarithromycin-based triple therapy for Helicobacter pylori eradication in a region with high rates of multiple drug resistance.

OBJECTIVES: Helicobacter pylori eradication rates with clarithromycin-based triple therapy are declining, and an alternative strategy is needed urgently. We sought to compare the efficacy of pretreatment antimicrobial susceptibility-guided vs. clarithromycin-based triple therapy for H. pylori eradication in a region with high rates of multiple drug resistance. METHODS: Consecutive H. pylori-infected patients with gastric epithelial neoplasms were randomized to receive antimicrobial susceptibility-guided therapy or clarithromycin-based triple therapy for 7 days. In patients in whom the infection was not eradicated, antibiotics were given according to an initial antimicrobial susceptibility test as a second-line therapy in both groups. Eradication rates, antibiotics resistance rates, and drug compliance owing to adverse effects were compared between the groups. RESULTS: In total, 114 patients were enrolled, and 112 completed the protocols. Drug compliance and side effects were similar between the groups. The intention-to-treat eradication rates were 94.7% (95% confidence interval (CI)=88.8-100%, 54/57) in the antimicrobial susceptibility-guided group and 71.9% (95% CI=60.2-83.5%, 41/57) in the clarithromycin-based triple therapy group after the initial treatment (P=0.002), whereas the per-protocol (PP) eradication rates were 96.4% (95% CI=91.5-100%, 54/56) in the antimicrobial susceptibility-guided group and 73.2% (95% CI=61.5-84.8%, 41/56) in the clarithromycin-based triple therapy group (P=0.001). In H. pylori with clarithromycin resistance, the eradication failure rate with first-line treatment was lower in the susceptibility-guided therapy group (0%, 0/12) compared with the clarithromycin-based triple therapy group (80.0%, 95% CI=59.7-100%, 12/15) by PP analysis (P<0.001). CONCLUSIONS: Pretreatment antimicrobial susceptibility-guided therapy is more effective than clarithromycin-based triple therapy for H. pylori eradication in a region with high rates of multiple drug resistance.

[Correlation between bacterial L-form infection, expression of HIF-1α/MMP-9 and vasculogenic mimicry in epithelial ovarian cancer].

The aim of the present study is to explore whether vasculogenic mimicry (VM) and bacterial L-form infection exist in human epithelial ovarian cancer (EOC) or not and to elucidate the correlation of L-form infection, expression of hypoxia inducible factor 1α (HIF-1α)/MMP-9 and VM. In 87 specimens of EOC and 20 specimens of ovarian benign epithelial tumor tissues, L-form infection was detected by Gram's staining, expression of HIF-1α/MMP-9 and VM were detected by immunohistochemical and histochemical staining. The results showed that the positive rates of HIF-1α and MMP-9 protein in EOC were 52.9% and 66.7%, while in benign epithelial tumor tissues, the positive rates were 10.0% and 10.0% respectively, and there were significant differences between them (P < 0.05). In EOC and benign epithelial tumor tissues, L-form infections ratios were 24.1% and 0, respectively, and the difference was also significant (P < 0.01). Expression of VM, HIF-1α and MMP-9 in EOC was significantly related to differentiation, abdominal implantation and lymph node metastasis and FIGO stage (P < 0.01). L-form infection had relationship with abdominal implantation, lymph node metastasis and FIGO stage (P < 0.01 or 0.05). The expression of HIF-1α had positive relationship with expression of MMP-9 and VM (r = 0.505, 0.585, respectively, P < 0.01); there was also a positive relationship between MMP-9 expression and VM (r = 0.625, P < 0.01). Overexpression of VM, HIF-1α and MMP-9 were related to poor prognosis: the survival rates were significantly lower in positive patients than those in negative patients (P < 0.05). And the group with L-form infection also had poor prognosis: the survival rates were lower than those in group without infection (P < 0.05). FIGO stage, expression of VM, HIF-1α and MMP-9 were independent prognosis factors of EOC (P < 0.05). The results suggest that L-form infection, the expression of HIF-1α, MMP-9 and VM in EOC are related to differentiation, lymph node metastasis, clinical stage and prognosis. Combined detection of these indexes has an important role in predicting the progression and prognosis of EOC.

Viral and bacterial aetiologies of epithelial ovarian cancer.

We sought to analyse the presence of human papillomavirus (HPV), Chlamydia trachomatis and cytomegalovirus (CMV) infection in women with epithelial ovarian carcinomas. Polymerase chain reaction (PCR)-based detection of microbial infections was carried out. A total of 39 tissue samples were analysed with consensus and type-specific primers for HPV, primers specific for the cryptic plasmid of Chlamydia and primers for glycoprotein B of CMV. The samples analysed showed 40%, 80% and 50% positivity for HPV, Chlamydia and CMV infection, respectively, in cancerous ovarian tissues. The HPV type detected was HPV 6, with its genome integrated to the host genome in case of both invasive and borderline tumours and existed episomally in healthy controls. The patients with Chlamydia (odds ratio [OR] 32; 95% confidence interval [CI] 3.33, 307.65) and CMV infection (OR 8; 95% CI 0.888, 72.10) are at significantly higher risk of development of ovarian tumours. The present study validates the theory of chronic infections and inflammation in the pathogenesis of epithelial ovarian cancer. Further seroepidemiological studies and large fresh tissue sampling may represent the real prevalence of infections among ovarian carcinoma patients. This study is the first of its kind in detecting the bacterial and viral aetiologies in the development of ovarian carcinoma among Indian women.

Chlamydia trachomatis and Mycoplasma genitalium plasma antibodies in relation to epithelial ovarian tumors.

OBJECTIVE: To assess associations of Chlamydia trachomatis and Mycoplasma genitalium antibodies with epithelial ovarian tumors. METHODS: Plasma samples from 291 women, undergoing surgery due to suspected ovarian pathology, were analyzed with respect to C. trachomatis IgG and IgA, chlamydial Heat Shock Protein 60-1 (cHSP60-1) IgG and M. genitalium IgG antibodies. Women with borderline tumors (n=12), ovarian carcinoma (n=45), or other pelvic malignancies (n=11) were matched to four healthy controls each. RESULTS: Overall, there were no associations of antibodies with EOC. However, chlamydial HSP60-1 IgG antibodies were associated with type II ovarian cancer (P=.002) in women with plasma samples obtained >1 year prior to diagnosis (n=7). M. genitalium IgG antibodies were associated with borderline ovarian tumors (P=.01). CONCLUSION: Chlamydial HSP60-1 IgG and M. genitalium IgG antibodies are in this study associated with epithelial ovarian tumors in some subsets, which support the hypothesis linking upper-genital tract infections and ovarian tumor development.

Involvement of VDAC1 and Bcl-2 family of proteins in VacA-induced cytochrome c release and apoptosis of gastric epithelial carcinoma cells.

OBJECTIVE: It is known that the vacuolating cytotoxin (VacA) could induce apoptosis. However, the mechanism remained to be elucidated. The aim of this study is to investigate the role of Bcl family of proteins (Bcl-2 and Bax) and the mitochondrial voltage-dependent anion channel (VDAC) in VacA-induced apoptosis of AGS cells. METHODS: Plasmid pGBKT7-VacA p58 was constructed and transfected into the AGS cells. RT-PCR and Western blotting were used to determine the expressions of cytochrome c, caspase-3, Bax, Bcl-2 and VDAC1 mRNA and proteins. RESULTS: VacA p58 can induce cytochrome c release and activate caspase-3 in AGS cells. It up-regulated the expressions of Bax and VDAC1 mRNA and proteins, and decreased the expression of Bcl-2 in AGS cells. CONCLUSION: VacA p58 induces apoptosis in AGS cells. This apoptotic process is associated with the up-regulation of Bax/VDAC1 and downregulation of Bcl-2. These findings suggest that the release of cytochrome c by VacA p58 is mainly through VDAC-dependent and Bcl-2 family-dependent pathways.

Effects of Helicobacter pylori Infection on gastric mucin expression.

AIMS: This study was performed to determine the gastric distributions of MUC5AC and MUC6 depending on Helicobacter pylori (H. pylori) infection, and to evaluate whether the expressions of MUC5 and MUC6 change in H. pylori-associated gastroduodenal diseases. In addition, MUC5AC and MUC6 expressional changes were investigated before and after H. pylori eradication. METHODS: In the 224 individuals (136 H. pylori-positive and 88 H. pylori-negative) who came from control (N=48), duodenal ulcer (N=35), benign gastric ulcer (N=61), dysplasia plus stomach cancer (N=80) groups, MUC5AC and MUC6 expressions were determined by immunohistochemical staining in the antrum and body, respectively. This staining for MUC5AC and MUC6 were reperformed in 113 of the 136 H. pylori-positive patients after successful H. pylori eradication by proton pump inhibitor-based triple therapy. RESULTS: (1) No difference was found between the H. pylori-positive and negative groups in terms of MUC5AC expression. In contrast, MUC6 expression was significantly lower in the H. pylori-positive group than in the H. pylori-negative group in the gastric body. Moreover, reduced MUC6 expression increased to the H. pylori-negative level after eradication. (2) Expressions of MUC5AC and MUC6 were significantly lower in the dysplasia plus cancer group than those of control in case of H. pylori positive. Similarly, MUC5AC and MUC6 expressions were significantly lower in the presence of atrophic gastritis with intestinal metaplasia in case of H. pylori positive. (3) Aberrant expressions of MUC6 in foveolar cells were observed in both antrum (11.3%) and body (5.3%) only in the H. pylori-positive group, but this reverted to normal after H. pylori eradication. CONCLUSION: These results suggest that H. pylori infection causes alterations of mucin expression, closely related with the development of gastric atrophy with intestinal metaplasia, probably contributing to carcinogenesis.

Gastric and intestinal phenotypes and histogenesis of advanced glandular stomach cancers in carcinogen-treated, Helicobacter pylori-infected Mongolian gerbils.

The Helicobacter pylori-infected Mongolian gerbil (MG) has been established as an appropriate animal model for studies of stomach cancer development. However, there have hitherto been no data on the phenotypic classification of glandular stomach cancers in H. pylori-infected and non-infected MG. We therefore examined the phenotypes of 50 and six advanced glandular stomach cancers in H. pylori-infected and non-infected MG, respectively, as well as adjacent non-neoplastic mucosa, using several gastrointestinal epithelial phenotypic markers. The lesions were divided phenotypically into 21 gastric, 24 gastric-and-intestinal mixed, four intestinal and one null types, with 90.0% of the lesions harboring gastric elements and 56.0% demonstrating intestinal phenotypic expression in H. pylori-infected MG. All six lesions were classified as gastric type in non-infected MG. There was no clear correlation with the presence of intestinal metaplasia in surrounding mucosa. In conclusion, our data suggest that most advanced adenocarcinomas retain a gastric cellular phenotype in the glandular MG stomach. Thus, it might be proposed that intestinal metaplasia is a paracancerous phenomenon rather than a premalignant condition. H. pylori infection may trigger intestinalization of both stomach cancers and non-neoplastic mucosa.

Effect of duodenogastric reflux on N-methyl-N'-nitro-N-nitrosoguanidine-induced glandular stomach tumorigenesis in Helicobacter pylori-infected Mongolian gerbils.

Both Helicobacter pylori (Hp) and bile acids are gastric carcinogens. An experimental model of duodenogastric reflux in Mongolian gerbils was developed and was used to study the effects of Hp infection and duodenogastric reflux on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced glandular stomach tumorigenesis independently and synergistically. Male Mongolian gerbils underwent both inoculation with Hp, and had duodenogastric reflux (DR) induced, or neither, followed by MNNG administration. Animals were sacrificed at week 40, and histopathological examination of their excised stomachs and serological investigation were performed. Glandular stomach adenocarcinomas were observed in animals that underwent Hp inoculation and/or induction of DR after MNNG administration, and glandular stomach adenomas were found in animals inoculated with Hp after MNNG administration. The incidence of glandular stomach tumors was significantly higher in animals inoculated with Hp after MNNG administration and in animals undergoing combined Hp inoculation, DR induction and MNNG administration than in animals only administered MNNG. These findings indicate that Hp infection has a stronger tumorigenic effect than the exposure to duodenal contents, and duodenal contents may attenuate the effect of Hp on glandular stomach tumorigenesis.