Molecular epidemiology, pathogenesis and prevention of gastric cancer

A review on the effect of COX-2-mediated mechanisms on development and progression of gastric cancer induced by nicotine

Smoking is a documented risk factor for cancer, e.g., gastric cancer. Nicotine, the principal tobacco alkaloid, would exert its role of contribution to gastric cancer development and progression through nicotinic acetylcholine receptors (nAChRs) and β-adrenergic receptors (β-ARs), which then promote cancer cell proliferation, migration and invasion. As a key isoenzyme in conversion of arachidonic acid to prostaglandins, cyclooxygenase-2 (COX-2) has been demonstrated to have a wide range of effects in carcinogenesis and tumor development. At present, many studies have reported the effect of nicotine on gastric cancer by binding to nAChR, as well as indirectly stimulating β-AR to mediate COX-2-related pathways. This review summarizes these studies, and also proposes more potential COX-2-mediated mechanisms. These events might contribute to the growth and progression of gastric cancer exposed to nicotine through tobacco smoke or cigarette substitutes. Also, this review article has therefore the potential not only to make a significant contribution to the treatment and prognosis of gastric cancer for smokers but also to the clinical application of COX-2 antagonists. In addition, this work also discusses the considerable challenges of this field with special reference to the future perspective of COX-2-mediated mechanisms in development and progression of gastric cancer induced by nicotine.

Use of folic acid supplementation to halt and even reverse the progression of gastric precancerous conditions: a meta-analysis

Background

Current data indicate that supplements such as folic acid and vitamin B may be beneficial in halting and even reversing atrophic gastritis, intestinal metaplasia and intraepithelial neoplasia, generally referred to as gastric precancerous conditions(GPC). However, there is no Meta-analysis article to evaluate the prevention and treatment of folic acid in the gastric precancerous conditions. We therefore conducted a meta-analysis to confirm the efficacy of folic acid in treating GPC.

Methods

Using a systematic review method, consider randomized controlled trials (RCT), including clinical trial reports, unpublished clinical trial data, and conference papers. The search time was been set from the database’s establishment to June 2, 2021. The language was not limited, using PubMed, SinoMed, Lancet, Web of Science, CNKI, Cochrane, Ovid, Science Direct, Embase, and EBSCO databases. Data were extracted using a pre-designed extraction tool and analysis was undertaken using RevMan5.2.Besides,we use Origin software to construct the Time-dose interval analysis.

Results

Of the 225 records identified, 13 studies involving 1252 patients (including 11 clinical controlled trials, 1 conference paper report and 1 unpublished research report) met the inclusion conditions. Folic acid dose maintained at 20–30 mg / d for 3–6 months may be beneficial to pathological changes of GPC. Moreover, in the 3 month treatment of 5 trials, the effect was more obvious when the folic acid dose was maintained at 30 mg / d. In the 7 trials, the symptom ineffective rate of GPC treated with folic acid was 32% (RR:0.32, 95% confidence interval CI:0.21–0.48), which was combined using a fixed analysis model; The effect of folic acid on gastric mucosal atrophy in 5 trials (RR: 1.61, 95%CI 1.07–2.41). The changes of folic acid on intestinal metaplasia in the 2 experiments (RR: 1.77, 95% CI: 1.32–2.37).The 2 results are combined using a fixed analytical model. However, the subgroup analysis of 9 trials revealed no significant effectiveness of symptom.

Conclusions

Our research showed that folic acid supplementation brings benefits in preventing and even reversing the progression of GPC in the stomach, and provided evidence for its potential clinical use in management of GPC.

Registration: The logn number of our Meta-anlysis on PROSPERO is CRD420223062.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02390-y.

Eradication of Helicobacter Pylori Infections and GERD: A systematic review and meta-analysis

BACKGROUND/AIMS

This study evaluates the association between the eradication of Helicobacter pylori (H. pylori) and gastroesophageal reflux disease (GERD).

MATERIALS AND METHODS

Relevant studies were identified by conducting literature search in PubMed, Cochrane, Embase, CNKI, VANFUN, and VIP databases. The prevalence rates of gastroesophageal reflux, heartburn, epigastric pain, and nausea were extracted from the identified research articles and were used in meta-analysis of relative risks (RR) to achieve an overall effect size of the relationship between H. pylori eradication and GERD.

RESULTS

A total of 19 randomized controlled trials were included in this meta-analysis. The prevalence of gastroesophageal reflux was significantly higher in patients with H. pylori eradication compared with patients without it (RR: 1.54, 95% CI: 1.06-2.24; p=0.02). A subgroup analysis did not identify any significant difference in GERD prevalence in studies conducted outside China (RR: 1.62, 95% CI: 0.98-2.68) or in China (RR: 1.30, 95% CI: 0.76-2.22). There were no significant differences in heartburn (RR: 1.03, 95% CI: 0.88-1.20), epigastric pain (RR: 0.98, 95% CI: 0.13-7.56), or nausea (RR: 0.44, 95% CI: 0.07-2.72) risk between patients with and without H. pylori eradication.

CONCLUSION

Eradication of H. pylori infection is found to be associated with GERD, although regional differences may exist in the prevalence. Well-designed studies especially those with stratification of patients' basic conditions are needed to seek refined evidence of the association between H. pylori eradication and the GERD.

Family History and Gastric Cancer Risk: A Pooled Investigation in the Stomach Cancer Pooling (STOP) Project Consortium

Simple Summary

Research is still required to establish the relationship between family history (FH) and gastric cancer (GC) in relation to different histological types and anatomical sites. The present work aimed to examine the influence of first-degree FH on the risk of GC, also according to the GC location and histological type, including 5946 cases and 12,776 controls from 17 studies of 11 countries in three continents participating in the Stomach Cancer Pooling (StoP) Project consortium. This analysis confirms the effect of FH on the risk of GC, reporting an approximately doubled risk, and provides further quantification of the risk of GC according to the subsite and histotype.

Abstract

Although there is a clear relationship between family history (FH) and the risk of gastric cancer (GC), quantification is still needed in relation to different histological types and anatomical sites, and in strata of covariates. The objective was to analyze the risk of GC according to first-degree FH in a uniquely large epidemiological consortium of GC. This investigation includes 5946 cases and 12,776 controls from 17 studies of the Stomach Cancer Pooling (StoP) Project consortium. Summary odds ratios (OR) and the corresponding 95% confidence intervals (CIs) were calculated by pooling study-specific ORs using fixed-effect model meta-analysis techniques. Stratified analyses were carried out by sex, age, tumor location and histological type, smoking habit, socioeconomic status, alcohol intake and fruit consumption. The pooled OR for GC was 1.84 (95% CI: 1.64–2.04; I2 = 6.1%, P heterogeneity = 0.383) in subjects with vs. those without first-degree relatives with GC. No significant differences were observed among subgroups of sex, age, geographic area or study period. Associations tended to be stronger for non-cardia (OR = 1.82; 95% CI: 1.59–2.05 for subjects with FH) than for cardia GC (OR = 1.38; 95% CI: 0.98–1.77), and for the intestinal (OR = 1.92; 95% CI: 1.62–2.23) than for the diffuse histotype (OR = 1.62; 95% CI: 1.28–1.96). This analysis confirms the effect of FH on the risk of GC, reporting an approximately doubled risk, and provides further quantification of the risk of GC according to the subsite and histotype. Considering these findings, accounting for the presence of FH to carry out correct prevention and diagnosis measures is of the utmost importance.

A global and physical mechanism of gastric cancer formation and progression

Gastric cancer is regarded as a major health issue for human being nowadays. The Helicobacter pylori (H. pylori) infection has been found to accelerate the development of gastritis and gastric cancer. Significant efforts have been made towards the understanding of the biology of gastric cancer on both genetic and epigenetic levels. However the physical mechanism behind the gastric cancer formation is still elusive. In this study, we constructed a model for investigating gastric cancer formation by explored the gastric cancer landscape and the flow flux. We uncovered three stable state attractors on the landscape: normal, gastritis and gastric cancer. The definition of each attractor is based on the biological function and gene expression levels. The global stabilities and the switching processes were quantified through the barrier heights and dominant kinetic paths. To investigate the underlying mechanism of the process from normal through the gastritis to the gastric cancer caused by genetic or epigenetic factors, we simulate the oncogenesis of gastric cancer through changes of several gene regulation strengths and H. pylori infection. The simulated results can illustrate the developmental and metastasis process of gastric cancer. Different H. pylori infection degrees accelerating the process from gastritis to gastric cancer can be quantified. Then we applied global sensitivity analysis, one key gene and four key regulations were found. These results are consist with the experimental results and can be used to design the polygenic anti-cancer agents through multiple key genes or regulations. The landscape approach provides a physical and simple strategy for analyzing gastric cancer in a systematic and quantitative way. It also offers new insight into treatment strategy for gastric cancer by adjusting relevant polygenic genes and regulations.

A Perforated Gastric Carcinoma: A Single-Center Experience

Objective

In this study, we aimed to describe clinicopathologic characteristics of the patients with a perforated gastric carcinoma, and to assess surgical approaches and possible factors affecting mortality and morbidity.

Material and Method

We retrospectively reviewed data of 18 patients who underwent emergent surgery for a perforated gastric carcinoma between January 2002 and December 2012. Data including surgical procedure, pathologic findings, complications, morbidity and mortality rates, and outcomes were evaluated.

Results

The mean age was 58 years. The most common tumor localization was antrum (55%), and 11 patients (61.1%) had Stage IV disease. Nine patients (50%) had a comorbid disease. Of the patients, primary suture + omentopexy was performed in 11 (61.1%) whereas total gastrectomy with D0 or D1 lymph node dissection in 5 (27.7%), subtotal gastrectomy with D0 lymph node dissection in 2 (11.1%), and 2-stage total gastrectomy with D2 lymph node dissection in 2 (11.1%). The complication rate was 50% with a mortality rate of 50%. Overall survival was 79 ± 97.89 days. Sepsis and the presence of comorbidities were found to increase early mortality (P = 0.00 and P = 0.028)

Conclusion

Our study results show that postoperative morbidity and mortality rates are still high in patients with a perforated gastric carcinoma. In stable patients, 1-step radical gastrectomy should be performed, while palliative surgery or 2-stage radical gastrectomy can be performed in patients with poor overall status and diffuse peritonitis. Early diagnosis and perforation management before the onset of diffuse peritonitis can decrease high mortality and morbidity rates.

Polyphenol Intake and Gastric Cancer Risk: Findings from the Stomach Cancer Pooling Project (StoP)

Simple Summary

Gastric cancer (GC) has the fifth highest incidence of any cancer type worldwide and the third highest mortality rate, so its prevention is very important. Among dietary factors, the consumption of fruit and vegetables has been inversely related to GC risk. Phenolic compounds may exert a favorable effect on the risk of several cancer types, including gastric cancer. However, selected polyphenol classes have not been adequately investigated in relation to GC. There is, however, no comprehensive analysis of polyphenols and GC risk methods to date. In order to provide a detailed evaluation of the relationship between dietary intake of polyphenols and GC risk, we analyzed data from the Stomach cancer Pooling (StoP) Project consortium.

Abstract

Phenolic compounds may exert a favorable effect on the risk of several cancer types, including gastric cancer (GC). However, selected polyphenol classes have not been adequately investigated in relation to GC. The aim of this study is to evaluate the association between the intake of polyphenols in relation to GC risk. We used data from the Stomach cancer Pooling (StoP) Project, including 10 studies from six countries (3471 GC cases and 8344 controls). We carried out an individual participant data pooled analysis using a two-stage approach. The summary odds ratios (ORs) of GC for each compound, and the corresponding 95% confidence intervals (95% CI), were computed by pooling study specific ORs obtained through multivariate logistic regression, using random effect models. Inverse associations with GC emerged for total polyphenols (OR = 0.67, 95% CI = 0.54–0.81, for the highest versus lowest quartile of intake), total flavonoids (OR = 0.73, 95% CI = 0.55–0.90), anthocyanidins (OR = 0.74, 95% CI = 0.56–0.92), flavanols (OR = 0.77, 95% CI = 0.66–0.88), flavanones (OR = 0.57, 95%CI = 0.44–0.69), total phenolic acids (OR = 0.75, 95%CI = 0.55–0.94), and hydroxybenzoic acids (OR = 0.73, 95%CI = 0.57–0.89). Results were consistent across strata of age, sex, social class, and smoking habit. Suggestive inverse associations were also found for flavonols (OR = 0.76, 95%CI = 0.51–1.01) and hydroxycinnamic acids (OR = 0.82, 95%CI = 0.58–1.06). Further investigations from longitudinal data are needed to confirm this association.

Interactions between Helicobacter pylori and gastroesophageal reflux disease

Interactions between Helicobacter Pylori (HP) and gastroesophageal reflux disease (GERD) are a complex issue. Several pathophysiological factors influence the development and the course of GERD, HP infection might be only one of these. Many studies emphasize the co-existence of these diseases. HP infection could contribute to GERD through both a protective and an aggressive role. Gastric acid secretion is a key factor in the pathophysiology of reflux esophagitis. Depending on the type of gastritis related to HP, acid secretion may either increase or decrease. Gastritis in corpus leads to hypoacidity, while antrum gastritis leads to hyperacidity. In cases of antral gastritis and duodenal ulcers which have hyperacidity, the expectation is an improvement in pre-existing reflux esophagitis after eradication of HP. In adults, HP infection is often associated with atrophic gastritis in the corpus. Atrophic gastritis may protect against GERD. Pangastritis which leads to gastric atrophy is commonly associated with CagA strains of HP and it causes more severe gastric inflammation. In case of HP-positive corpus gastritis in the stomach, pangastritis, and atrophic gastritis, reflux esophagitis occurs frequently after eradication of HP. Nonetheless, as a predisposing disease of gastric cancer, HP should be treated. In conclusion, as the determinative factors affecting GERD involving in HP, detailed data on the location of gastric inflammation and CagA positivity should be obtained by the studies at future.

The roles of PD-1/PD-L1 and its signalling pathway in gastrointestinal tract cancers

Cancer immunotherapy has been increasingly applied in the treatment of advanced malignancies. Consequently, immune checkpoints have become a major concern. As PD-1 is an important immunomodulatory protein, the blockade of PD-1 and its ligand PD-L1 is a promising tumour immunotherapy for human carcinoma. In this review, we first discuss the role of the PD-1/PD-L1 interaction in gastrointestinal tract cancers. Targeting PD-1 and PD-L1 in immune cells and tumour cells may show remarkable efficiency in gastrointestinal tract cancers. Second, the PD-1/PD-L1-associated signalling pathway involved in cancer immunotherapy in gastrointestinal tract cancers is discussed. Most importantly, this review summarizes the PD-1/PD-L1-targeted immunotherapy combinations with relevant signalling pathways, which may result in a breakthrough for the treatment of gastrointestinal tract cancers, such as gastric cancer, colorectal cancer and liver cancer. Meanwhile, the review provides a deeper insight into the mechanism of checkpoint blockade immunotherapies.

Expression analysis of matrix metalloproteinase-13 in human gastric cancer in the presence of Helicobacter Pylori infection

BACKGROUND

Matrix metalloproteinases (MMPs) can degrade essentially the extracellular matrix (ECM) components. MMPs are important regulators of tumor growth; hence the enzymes are considered as important targets for cancer therapy. MMP-13 is specially activated in gastric cancer and promotes the invasiveness of the primary tumors. Helicobacter Pylori (H.pylori) interacts with gastric epithelial cells and stimulates it to produce MMP-13in vitro.

OBJECTIVE

The relation between MMP-13 gene expression and clinicopathological characteristics of gastric cancer in the presence of H.pylori infection was investigated in fifty patients.

METHODS

The level of MMP-13 gene expression was measured by quantitative Real-time PCR method and was evaluated between two groups of normal and carcinomatous tissues.

RESULTS

The results showed 30% elevation of MMP-13 expression in tumor tissues. H.pylori infection did not have a significant effect on the expression of MMP-13. There was a correlation between gene expression and tumor type (P value = 0.032). In addition, there was a significant correlation between MMP-13 gene expression and tumor stage in intestinal group (P value = 0.023).

CONCLUSIONS

Based on the results, it might be concluded that in intestinal group, immune system plays an important role in reducing gene expression. Results also showed over expression (60%) in diffuse group. These findings suggest that using MMP-13 inhibitors in diffuse group might contribute to the control of tumor growth.

Prognostic value of tripartite motif containing 29 expression in patients with gastric cancer following surgical resection

Tripartite motif containing 29 (TRIM29) dysregulation serves an important function in the progression of numerous types of cancer, but its function in the prognosis of patients with gastric cancer remains unknown. The present study assessed the prognostic value of TRIM29 in patients with gastric cancer following surgical resection. A total of 243 fresh gastric adenocarcinoma and adjacent normal tissues were continuously retrieved from patients who underwent curative surgery for gastric cancer at the Cancer Hospital of Henan Province (Zhengzhou, China) between January 2005 and December 2011. The reverse transcription-quantitative polymerase chain reaction was performed to assess TRIM29 expression. The association between TRIM29 expression and clinicopathological features and prognosis was subsequently evaluated. The results of the present study revealed that the expression of TRIM29 was increased in the gastric cancer tissues compared with the normal adjacent tissues, and that upregulated expression of TRIM29 was associated with tumor cell differentiation, tumor stage, lymph node metastasis, and tumor-node-metastasis (TNM) stage. In the training and validation data, high TRIM29 expression was associated with poor overall survival in patients with gastric cancer. Furthermore, multivariate analysis identified that TRIM29 expression was an independent prognostic factor for overall survival, in addition to TNM stage and Lauren classification. Combining TRIM29 expression with the TNM staging system generated a novel predictive model that exhibited improved prognostic accuracy for overall survival in patients with gastric cancer. The present study revealed that TRIM29 was an independent adverse prognostic factor in patients with gastric cancer. Incorporating TRIM29 expression level into the TNM staging system may improve risk stratification and render prognosis more accurate in patients with gastric cancer.

Association between SNPs in microRNA machinery genes and gastric cancer susceptibility, invasion, and metastasis in Chinese Han population

Objective

The present study investigates the influence of genetic variants in miRNA machinery genes (DROSHA, DICER, AGO1, and GEMIN4) on gastric cancer in Chinese Han population, further revealing the genetic mechanisms of gastric cancer occurrence and development.

Methods

Genotyping of single nucleotide polymorphisms (SNPs) was performed in 628 patients with GC and 502 frequency-matched (age and gender) controls by the high resolution melting (HRM) method.

Results

The SNPs rs3742330 (DICER) and rs7813 (GEMIN4) were associated with susceptibility to gastric cancer (P = 0.002 and 0.010, respectively). Stratified analysis showed that the G allele of rs3742330 and genotype TT as well as T allele of rs7813 were associated with a later stage of gastric cancer (P=0.027, 0.032 and 0.018, respectively). Furthermore, the genotype TT and T allele of rs7813 appeared to be associated with a higher level of lymphatic metastasis of gastric cancer (P=0.021 and 0.030, respectively), while the genotype AA and A allele of rs636832 (AGO1) were correlated with a lower level of lymphatic metastasis of gastric cancer (P=0.016 and 0.041, respectively). There was no significant association between rs10719 (DROSHA) and gastric cancer.

Conclusion

The present data demonstrated that genetic variants in miRNA machinery genes had a significant association with GC susceptibility (DICER and GEMIN4) and malignant behavior such as tumor stage (DICER and GEMIN4) and lymphatic metastasis of GC (GEMIN4 and AGO1) in Chinese Han population.

Association between CHFR gene hypermethylation and gastric cancer risk: a meta-analysis

BACKGROUND

The association between the hypermethylation of CHFR gene and gastric cancer risk has been investigated by a number of studies. However, the sample size of the majority of these studies was very small. To get a more a convincing conclusion, here we performed a meta-analysis of the previously published studies to assess the association between CHFR methylation and the risk of gastric cancer.

METHODS

Eligible studies were identified by searching the MEDLINE/PubMed, Embase, and Web of Science databases before May 2016 without any language restriction. The strength of the association was estimated by odds ratio with its 95% confidence interval (CI).

RESULTS

Totally 1,399 samples, including 758 gastric cancer cases and 641 controls, from 13 studies were included in the present meta-analysis. Compared with non-cancer controls, the pooled OR of CHFR methylation in gastric cancer patients was 9.08 (95% CI: 6.40-12.88, P<0.001), suggesting that the methylation of CHFR was significantly associated with increased risk of gastric cancer. Similar results were observed when subgroup analyses were performed stratified by country, ethnicity, and methylation testing methods.

CONCLUSION

Our meta-analysis showed a strong positive correlation between CHFR methylation and risk of gastric cancer, suggesting that CHFR methylation might be a promising biomarker for the diagnosis of gastric cancer.

Diet-Related Stomach Cancer Behavior Among Iranian College Students: A Text Messaging Intervention

Background: Stomach cancer is one of the five most common cancers in Iran. This study examined the effectiveness of a mobile telephone short-message service (SMS) based-education intervention using Health Belief Model (HBM) variables in improving dietary behavior in terms of stomach cancer prevention among a sample of Iranian female college students. Materials and Methods: In this quasi-experimental study, 124 female college students in the dormitories of Yazd University, Yazd, Iran were randomly selected and assigned to either the intervention (n=62) or the control group (n=62). Information (data) regarding HBM variables and dietary behavior related to stomach cancer prevention was collected by a self-administrated questionnaire. Forty eight messages were designed and sent to the participants’ phones in the intervention group during the 48-day intervention period. Two groups were followed-up one month after the intervention delivered via SMS. Results: There were significant differences in HBM variables (except for the perceived severity) and the preventive dietary behaviors for stomach cancer in the intervention group compared to the comparison group following the education intervention delivered via SMS. Conclusions: SMS-delivered nutrition education intervention can be a practical strategy to improve dietary behavior related to stomach cancer prevention.

A polymorphism at the microRNA binding site in the 3'-untranslated region of C14orf101 is associated with the risk of gastric cancer development

MicroRNAs (miRNAs) bind to the 3'-untranslated regions (3'-UTRs) of mRNAs, affecting translation and regulating cell differentiation, tumorigenesis and apoptosis. Genetic polymorphisms in these regions in target genes are able to affect the binding affinity between miRNA and target genes, ultimately affecting the expression of individual miRNAs. In the present case-control study, genotyping of 5 microRNA single nucleotide polymorphisms (SNPs) located at the binding site of the 3'-UTR of RYR3 (rs1044129), C14orf101 (rs4901706), KIAA0423 (rs1053667), GOLGA7 (rs11337) and KRT81 (rs3660) genes was assessed in order to investigate its role in gastric cancer (GC). The results indicated that the rs4901706 SNP, which is located in the 3'-UTR of C14orf101, was associated with GC development risk, as determined by χ² analysis (relative risk, 1.630; 95% confidence interval, 1.070-2.483; P=0.022). A Renilla/luciferase reporter assay also indicated the different binding affinity between the SNP of rs4901706 and microRNA. In conclusion, rs4901706 SNP of C14orf101 gene in the microRNA binding site may be used as a valuable biomarker when predicting GC risk.

Prognostic Significance of MiR-34a Expression in Patients with Gastric Cancer after Radical Gastrectomy

BACKGROUND

MiR-34a dysregulation has been implicated in tumorigenesis and progression of gastric cancer, but its role in prognosis of patients with gastric cancer remains unknown. The aim of this study was to investigate the expression and prognostic significance of miR-34a in gastric cancer patients after radical gastrectomy.

METHODS

Quantitative real-time polymerase chain reaction was performed to detect the expression of miR-34a in human gastric cancer cell lines and tissues in 76 patients with gastric adenocarcinoma from China. Results are assessed for association with clinical features and overall survival (OS) using Kaplan-Meier analysis. Prognostic values of miR-34a expression and clinical outcomes were evaluated by Cox regression analysis. A molecular prognostic stratification scheme incorporating miR-34a expression was determined using receiver operating characteristic analysis.

RESULTS

The results show that the expression level of miR-34a was decreased in human gastric cancer cell lines and tissues, and down-regulated expression of miR-34a was associated with Lauren classification (P = 0.034). Decreased miR-34a expression in gastric cancer tissues was positively correlated with poor OS of gastric cancer patients (P = 0.013). Further multivariate Cox regression analysis suggested that miR-34a expression was an independent prognostic indicator for gastric cancer (P = 0.027). Applying the prognostic value of miR-34a expression to tumor node metastasis (TNM) stage system showed a better prognostic value in patients with gastric cancer than miR-34a expression (P = 0.0435) or TNM stage (P = 0.0249) alone.

CONCLUSION

The results reinforce the critical role for the down-regulated miR-34a expression in gastric cancer and suggest that miR-34a could be a prognostic indicator for this disease.

The Effects of Dinner-to-Bed Time and Post-Dinner Walk on Gastric Cancer Across Different Age Groups: A Multicenter Case-Control Study in Southeast China

Gastric cancer (GC) remains a major killer throughout the world. Despite the dramatic decrease in GC over the last century, its etiology has not yet been well characterized. This study investigated the possible independent and combined effects of the dinner-to-bed time and post-dinner walk on the risk for GC across different age groups. A population-based, case-control study was conducted in southeast China, including 452 patients with GC and 465 age-, race-, and gender-matched controls. A self-designed questionnaire was used to collect information on demographic characteristics, dinner-to-bed time, post-dinner walk, and other behavioral factors. Conditional logistic regression models were used to estimate the effects of the dinner-to-bed time and post-dinner walk as well as their joint effect on the risk for GC across different age groups. Individuals with dinner-to-bed time <3 hours were more prone to have GC (P < 0.001), and the shorter the dinner-to-bed time was, the higher was the risk for GC (Ptrend < 0.001). Post-dinner nonwalk was associated with a 2.9-fold increased risk for GC compared with post-dinner walk (adjusted odds ratio [AOR] = 2.942, 95% confidence intervals [95% CIs] = 2.072-4.179). The interaction effect of dinner-to-bed time and post-dinner walk on GC risk was detected (AOR = 1.862, 95% CIs = 1.584-3.885, synergy index [SI] = 2.654, 95% CIs = 2.27-3.912). Participants with dinner-to-bed time <3 hours who did not walk after dinner were 7.4 times likely to suffer from GC (AOR = 7.401, 95% CIs = 4.523-13.16) than those with dinner-to-bed time ≥4 hours who took such walk. The risk of GC due to dinner-to-bed time <3 hours, post-dinner nonwalk and their interaction was positively correlated with age. The strongest risk was observed among people ≥70 years old, but the effects were not significant for people ≤55 years old. Dinner-to-bed time <3 hours and post-dinner nonwalk are independent risk factors for GC; the synergistic interaction between the 2 factors was positively related to age, which might significantly increase the risk for GC among people >55 years old.

Frequency of Epstein--Barr virus infection as detected by messenger RNA for EBNA 1 in histologically proven gastric adenocarcinoma in patients presenting to a tertiary care center in South India

BACKGROUND

Epstein-Barr virus (EBV)-associated gastric carcinoma is a relatively uncommon entity detected in approximately 10% of gastric adenocarcinoma.

OBJECTIVE

The purpose of this study is to estimate the frequency of EBV-associated gastric carcinoma and also to assess the nature of presentation, any significant difference between this subgroup and EBV-negative gastric adenocarcinomas with respect to age and sex predilection, lymph nodal status, site of presentation.

MATERIALS AND METHODS

We prospectively analyzed 100 cases of gastric adenocarcinoma who underwent either a partial or total gastrectomy during the period from March 2010 to August 2011. The tumour and the corresponding normal gastric tissue from the same patient were analyzed for the presence of Epstein-Barr nuclear antigen 1 (EBNA1) messenger ribonucleic acid (mRNA) by real-time polymerase chain reaction (PCR).

RESULT

EBV was detected in 6% cases of gastric adenocarcinoma. All the positive patients were males. The majority of cases involved the proximal stomach and there was variable lymph nodal involvement.

CONCLUSION

Our study endorses that there is an association between EBV infection and gastric adenocarcinoma in the Indian population. There was no significant difference between this subgroup and EBV-negative gastric adenocarcinomas with respect to age and sex predilection, lymph nodal status and site of presentation. Short-term follow-up of this subgroup of patients seems to indicate a good overall prognosis after appropriate treatment. However, a larger study with long-term follow-up is needed to further establish the role of EBV in gastric adenocarcinoma in this study population.

Evaluation of insulin like growth facror-1 genetic polymorphism with gastric cancer susceptibility and clinicopathological features

Gastric cancer (GC) is one of the most common malignancies in the world. It is the first cause of cancer deaths in both sexes In Iranian population. Circulating insulin-like growth factor-one (IGF-1) levels have been associated for gastric cancer. IGF-1 protein has central roles involved in the regulation of epithelial cell growth, proliferation, transformation, apoptosis and metastasis. Single nucleotide polymorphism in IGF-1 regulatory elements may lead to alter in IGF-1 expression level and GC susceptibility. The aim of this study was to investigate the influence of IGF-1 gene polymorphism (rs5742612) on risk of GC and clinicopathological features for the first time in Iranian population. In total, 241 subjects including 100 patients with GC and 141 healthy controls were recruited in our study. Genotypes were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay with DNA from peripheral blood. The polymorphism was statistically analyzed to investigate the relationship with the risk of GC and clinicopathological properties. Logistic regression analysis revealed that there was no significant association between rs5742612 and the risk of GC. In addition, no significant association between genotypes and clinicopathological features was observed (p value>0.05). The frequencies of the CC, CT, and TT genotypes were 97%, 3%, and 0%, respectively, among the cases, and 97.9%, 2.1%, and 0%, respectively, among the controls. CC genotype was more frequent in cases and controls. The frequencies of C and T alleles were 98.9% and 1.1% in controls and 98.5% and 1.5% in patient respectively. Our results provide the first evidence that this variant is rare in Iranian population and it may not be a powerful genetic predisposing biomarker for prediction GC clinicopathological features in an Iranian population.

Clinical Significance of MiR-137 Expression in Patients with Gastric Cancer After Radical Gastrectomy

The dysregulation of miR-137 plays vital roles in the oncogenesis and progression of various types of cancer, but its role in prognosis of gastric cancer patients remains unknown. This study was designed to investigate the expression and prognostic significance of miR-137 in gastric cancer patients after radical gastrectomy. Quantitative real-time PCR (qRT-PCR) was performed to evaluate the expression of miR-137 in human gastric cancer cell lines and tissues in patients with gastric adenocarcinoma. Results were assessed for association with clinical factors and overall survival by using Kaplan-Meier analysis. Prognostic values of miR-137 expression and clinical outcomes were evaluated by Cox regression analysis. The results exhibited that the expression level of miR-137 was decreased in human gastric cancer cell lines and tissues, and down-regulated expression of miR-137 was associated with tumor cell differentiation, N stage, and TNM stage. Decreased miR-137 expression in gastric cancer tissues was positively correlated with poor overall survival of gastric cancer patients. Further multivariate Cox regression analysis suggested that miR-137 expression was an independent prognostic indicator for gastric cancer except for TNM stage. Applying the prognostic value of miR-137 expression to TNM stage III group showed a better risk stratification for overall survival. In conclusion, the results reinforced the critical role for the down-regulated miR-137 expression in gastric cancer and suggested that miR-137 expression could be a prognostic indicator for this disease. In addition, these patients with TNM stage III gastric cancer and low miR-137 expression might need more aggressive postoperative treatment and closer follow-up.

Proteomics in gastric cancer research: Benefits and challenges

Among various cancers, gastric cancer (GC) exhibits relatively high morbidity and mortality rate worldwide. The lack of effective methods in early detection and diagnosis, and immediate therapies makes treating such disease a challenge for both clinicians and oncologists. Proteomics has emerged as a promising technology platform for rationally identifying biomarkers and novel therapeutic targets for GC, as well as discovering underlying mechanisms of carcinogenesis. Its application has greatly benefited mechanistic studies of this disease. This review will demonstrate the applications of proteomic technology in GC research. The advantages and shortcomings of this technology, as reflected by current studies, will also be discussed to improve and expand its application in the field of cancer research.

The effect of Helicobacter pylori eradication therapy on the development of gastroesophageal reflux disease

BACKGROUND

It is uncertain whether the Helicobacter pylori eradication therapy makes a role in the progression of gastroesophageal reflux disease (GERD).

METHODS

A meta-analysis was undertaken to investigate the effect of H pylori eradication therapy on the development of GERD.

RESULTS

Overall, 16 cohort studies were included. The authors demonstrated that H pylori eradication had no significant effect on the occurrence of GERD in these cohort studies (odds ratio = 0.87, 95% confidence interval = 0.66-1.14, I = 32.4%, P = 0.103).

CONCLUSIONS

In general, H pylori eradication has no significant effect on the development of GERD in the long term. However, eradication therapy should be taken once there is H pylori infection, because H pylori infection is acknowledged to be a major cause of acute and chronic gastritis and peptic ulcer diseases and has been established as a definite etiologic factor for gastric cancer.

Interference with the β-catenin gene in gastric cancer induces changes to the miRNA expression profile

Aberrant activation of the Wnt/β-catenin signaling pathway plays a major role in carcinogenesis and the progression of many malignant tumors, especially gastric cancer (GC). Some research has suggested that expression of the β-catenin protein is associated with clinicopathologic factors and affects the biological behaviors of GC cells. However, the mechanism of these effects is not yet clear. Studies show that the Wnt/β-catenin pathway regulates some miRNAs. We hypothesize that oncogenic activation of β-catenin signaling is involved in the formation of GC through regulating certain microRNAs (miRNAs). The results of the current study demonstrate that expression of the β-catenin protein is associated with many clinicopathologic characteristics including the degree of differentiation, depth of tumor invasion, tumor site, and 5-year survival rate. We found that silencing the expression of β-catenin with lentiviruses could delay cell proliferation, promote apoptosis, weaken the invasive power of GC cells, and increase the sensitivity of GC cells to 5-fluorouracil in vitro. Using miRNA microarrays to detect changes in the miRNA transcriptome following interference with β-catenin in GC cells, we found that miR-1234-3p, miR-135b-5p, miR-210, and miR-4739 were commonly upregulated and that miR-20a-3p, miR-23b-5p, miR-335-3p, miR-423-5p, and miR-455-3p were commonly downregulated. These data provide a theoretical basis for the potential interaction between miRNA and the β-catenin signaling pathway in GC.

Single-nucleotide polymorphisms of microRNA processing machinery genes are associated with risk for gastric cancer

Recent studies demonstrate that microRNA-related single-nucleotide polymorphisms (miR-SNPs) are associated with the development of numerous human cancers. In this study, we investigated six miR-SNPs in microRNA processing machinery genes, including rs11077 of the XPO5 gene, rs14035 of the RAN gene, rs3742330 of the Dicer gene, rs9623117 of the TNRC6B gene, rs197412 of the GEMIN3 gene, and rs2740348 of the GEMIN4 gene, in gastric cancer patients and subsequently evaluated their potential roles in gastric cancer risk in a case control study. The results indicate that the C/C genotype of rs14035 from RAN, the A/A genotype of rs3742330 from Dicer, and the T/T genotype of rs9623117 from TNRC6B are significantly associated with gastric cancer risk. In conclusion, these miR-SNPs can be used as predictive biomarkers in gastric cancer.

Association between polymorphisms of microRNA-binding sites in integrin genes and gastric cancer in Chinese Han population

Highly elevated expression of integrin has been observed in a variety of malignant tumors. Single nucleotide polymorphisms (SNPs) in the microRNA-binding sites in the 3' UTR region of target genes may result in the level change of target gene expression and subsequently susceptible to diseases, including cancer. In this study, we aimed to investigate the association between polymorphisms of microRNA-binding sites of integrin genes and gastric cancer (GC) in Chinese Han population. Five SNPs of the microRNA-binding sites in the 3' UTR region of integrin genes (rs1062484 C/T in ITGA3, rs17664 A/G in ITGA6, rs3809865 A/T in ITGB3, rs743554 C/T in ITGB4, and rs2675 A/C in ITGB5) were studied using high resolution melting (HRM) analysis in 1000 GC patients and 1000 unrelated controls. The polymorphism of SNP rs2675 was associated with susceptibility of GC [odds ratio (OR) = 0.52, 95% confidence interval (CI) = 0.28-0.97, P = 0.028]. In addition, genotype AA of rs2675 and genotype GG of rs17664 were associated with a lower chance of GC at stage 1b [OR = 0.39 (0.18-0.85), P = 0.009; and OR = 0.37 (0.17-0.78), P = 0.004, respectively]; also, the frequency of allele G of rs17664 was associated with a lower chance of stage 1b tumor [OR = 0.50 (0.26-0.95), P = 0.021]. Furthermore, the frequency of genotype AA and allele A of rs3809865 were associated with a higher risk of stage 4 GC [OR = 1.85 (1.11-3.09), P = 0.012; and OR = 1.52 (0.99-2.33), P = 0.043, respectively]. For rs17664, GG genotype and allele G appeared to be associated with a higher risk with GC with lymphatic metastasis 3b [OR = 1.76 (1.00-3.11), P = 0.036; and OR = 1.64 (0.98-2.75), P = 0.048, respectively]. Our data suggest that polymorphisms of the microRNA-binding sites in the 3' UTR region of integrin are associated with GC susceptibility (rs2675), tumor stage (rs2675, rs17664, and rs3809865), and lymphatic metastasis (rs17664) in Chinese Han population.

Glutathione S-transferase gene GSTM1, gene-gene interaction, and gastric cancer susceptibility: evidence from an updated meta-analysis

Background

The null genotype of GSTM1 have been implicated in gastric cancer risk, but numerous individual studies showed mixed, or even conflicting results. Thus, a meta-analysis was performed.

Results

We identified 54 individual studies involving 9,322 cases and 15,118 controls through computer-based searches of PubMed, Embase, and Cochrane Library. It was found that the null genotype of GSTM1 was associated with an increased gastric cancer risk (OR = 1.207, 95% CI: 1.106-1.317, P < 0.001), under the random-effects model (I² : 49.9%, P_Q <0.001). From stratification analyses for ethnicity, alcohol drinking, Helicobacter pylori infection, an effect modification of gastric cancer risk was found in the subgroups of ethnicity, smoking status, Helicobacter pylori infection, whereas null result was found in the subgroups of alcohol drinking. We also undertook gene-gene interaction analysis between GSTM1 and GSTT1 genes for gastric cancer risk, and the results indicated that the dual null genotypes of GSTM1 and GSTT1 might elevate the risk of gastric cancer (OR = 1.505, 95% CI: 1.165-1.944, P = 002).

Conclusions

This meta-analysis suggests that the null genotype of GSTM1 may be a important genetic risk factor for gastric cancer development.

Dysregulation of apoptotic signaling pathways by interaction of RPLP0 and cathepsin X/Z in gastric cancer

Cathepsin X (CTSX, also called cathepsin Z/P) is a cysteine protease that still plays an unknown role in human cancer. It has been shown to bind cell surface heparin sulphate proteoglycans and integrins, indicating possible functions of CTSX in cellular adhesion, phagocytosis, and immune response. Our previous studies have shown an association between Helicobacter pylori (H. pylori) infection, a strong up-regulation of CTSX, and development of gastric cancer. In this study, yeast two-hybrid analysis revealed that RPLP0, a ribosomal protein P0, interacts with the human CTSX protein in gastric cancer. The CTSX/RPLP0 interaction was confirmed by co-immunoprecipitation assays. In addition, co-localization studies in cancer cell line N87 and gastric cancer tissue samples were performed. Laserscan microscopy revealed a shuttling of RPLP0 (and CTSX) from cytoplasm to the nucleus after CTSX knockdown. Down-regulation of RPLP0 resulted in G1 arrest of gastric cancer cells, whereas knockdown of CTSX led to G1 arrest and apoptosis after 48 h. Knockdown of both proteins caused increased apoptosis. RPLP0 deficiency could suppress cell growth and cell cycle progression by down-regulating CDK2. It was further demonstrated that RPLP0 affected p21 expression, but did not change the expression of Cyclin E. Down-regulation of both proteins at least through CDK2 suggests an anti-apoptotic effect on gastric cancer cells and opens up new possibilities for apoptotic immune modulation and gastric cancer therapy.

Gene-diet interactions in gastric cancer risk: A systematic review

AIM: To conduct a systematic review of the published epidemiological studies investigating the association of the interactions between gene variants and dietary intake with gastric cancer risk.

METHODS: A literature search was conducted in PubMed, EMBASE, and MEDLINE for articles published between January 2000 and July 2013, and 38 studies were identified. Previous studies included various dietary factors (e.g., fruits and vegetables, soybean products, salt, meat, and alcohol) and genetic variants that are involved in various metabolic pathways.

RESULTS: Studies suggest that individuals who carry high-risk genetic variants and demonstrate particular dietary habits may have an increased risk of gastric cancer compared with those who do not carry high-risk genetic variants. Distinctive dietary patterns and variations in the frequency of genetic variants may explain the higher incidence of gastric cancer in a particular region. However, most previous studies have limitations, such as a small sample size and a retrospective case-control design. In addition, past studies have been unable to elucidate the specific mechanism in gene-diet interaction associated with gastric carcinogenesis.

CONCLUSION: Additional large prospective epidemiological and experimental studies are required to identify the gene-diet metabolic pathways related to gastric cancer susceptibility.

CARP is a potential tumor suppressor in gastric carcinoma and a single-nucleotide polymorphism in CARP gene might increase the risk of gastric carcinoma

Background

The caspase-associated recruitment domain-containing protein (CARP) is expressed in almost all tissues. Recently, the tumor-suppressive function of CARP was discovered and attracted increasing attention. This study aimed to investigate the role of CARP in the carcinogenesis of human gastric carcinoma.

Methodology/Principal Findings

Compared with normal gastric tissue, the downregulation of CARP expression was observed in gastric carcinoma tissue by cDNA array and tissue microarray assay. In vitro, the gastric carcinoma cell line (BGC-823) was stably transfected with pcDNA3.1B-CARP or plus CARP siRNA, and we used MTT, flow cytometry, cell migration on type I collagen, cell-matrix adhesion assay and western blot analysis to investigate the potential anti-tumor effects of CARP. The data showed that overexpressing CARP suppressed the malignancy of gastric carcinoma BGC-823 cell line, including significant increases in apoptosis, as well as obvious decreases in cell proliferation, migration, adhesion ability, and tumor growth. The tumor-suppressive effects of CARP were almost restored by siRNA-directed CARP silence. In addition, overexpression of CARP induced G1 arrest, decreased the expressions of cyclin E and CDK2, and increased the expressions of p27, p53 and p21. In vivo, the tumor-suppressive effect of CARP was also verified. A single-nucleotide polymorphism (SNP) genotype of CARP (rs2297882) was located in the Kozak sequence of the CARP gene. The reporter gene assay showed that rs2297882 TT caused an obvious downregulation of activity of CARP gene promoter in BGC-823 cells. Furthermore, the association between rs2297882 and human gastric carcinoma susceptibility was analyzed in 352 cases and 889 controls. It displayed that the TT genotype of rs2297882 in the CARP gene was associated with an increased risk of gastric carcinoma.

Conclusions/Significance

CARP is a potential tumor suppressor of gastric carcinoma and the rs2297882 C>T phenotype of CARP may serve as a predictor of gastric carcinoma.

Association of XRCC1 gene polymorphisms with susceptibility to gastric cancer in Chinese Han population

OBJECTIVES

Gastric cancer is one of the most frequently causing cancer-related deaths worldwide. The X-ray repair complementing group 1 gene (XRCC1) is an important candidate gene for influencing gastric cancer risk. This study aimed to evaluate the associations between XRCC1 genetic variants and gastric cancer susceptibility in Chinese Han population.

METHODS

Four hundred twenty-four gastric cancer patients and 430 cancer-free controls were enrolled. Two genetic variants (c.1254C>T and c.1779C>G) of XRCC1 gene were genotyped by created restriction site-polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism methods, respectively.

KEY FINDINGS

Results from this study indicated that the allele and genotype frequencies of these two genetic variants were statistically different between gastric cancer patients and cancer-free controls. The association analyses suggested that these two genetic variants were statistically associated with the increased risk of gastric cancer (for c.1254C>T, T versus C: odds ratio (OR) = 1.44, 95% confidence interval (CI) 1.17-1.77; for c.1779C>G, G versus C: OR = 1.51, 95% CI 1.22-1.86). The allele-T of c.1254C>T and allele-G c.1779C>G genetic variants may contribute to the susceptibility to gastric cancer in Chinese Han population.

CONCLUSION

Our data suggest that these two genetic variants might be used as molecular markers for evaluating the susceptibility to gastric cancer.

Anti-inflammatory properties of gastric-derived Lactobacillus plantarum XB7 in the context of Helicobacter pylori infection

BACKGROUND

Helicobacter pylori colonization of the gastric epithelium induces interleukin-8 (IL-8) production and inflammation leading to host cell damage. We searched for gastric-derived Lactobacillus with the ability to suppress H. pylori-induced inflammation.

MATERIALS AND METHODS

Conditioned media from gastric-derived Lactobacillus spp. were tested for the ability to suppress H. pylori-induced IL-8 production in AGS gastric epithelial cells. IL-8 protein and mRNA levels were measured by ELISA and qPCR, respectively. The changes on host cell signaling pathway were analyzed by Western blotting and the anti-inflammatory effect was tested in a Sprague-Dawley rat model.

RESULTS

Conditioned media from L. salivarius B101, L. rhamnosus B103, and L. plantarum XB7 suppressed IL-8 production and IL-8 mRNA expression in H. pylori-induced AGS cells without inhibiting H. pylori growth. Conditioned media from LS-B101, LR-B103, and LP-XB7 suppressed the activation of NF-κB in AGS cells, while strain LP-XB7 also suppressed c-Jun activation. The anti-inflammatory effect of LP-XB7 was further assessed in vivo using a H. pylori-infected Sprague-Dawley rat model. Strain LP-XB7 contributed to a delay in the detection and colonization of H. pylori in rat stomachs, attenuated gastric inflammation, and ameliorated gastric histopathology. Additionally, the administration of LP-XB7 correlated with the suppression of TNF-α and CINC-1 in sera, and suppression of CINC-1 in the gastric mucosa of H. pylori-infected rats.

CONCLUSIONS

These results suggest that L. plantarum XB7 produces secreted factors capable of modulating inflammation during H. pylori infection, and this probiotic Lactobacillus strain shows promise as an adjunctive therapy for treating H. pylori-associated disease.

DNA methylation of trefoil factor 1 (TFF1) is associated with the tumorigenesis of gastric carcinoma

Trefoil factor 1 (TFF1) is a tumor suppressor gene that encodes a peptide belonging to the trefoil factor family of protease‑resistant peptides. Although TFF1 expression is frequently lost in gastric carcinomas (GCs), the tumorigenic pathways that are affected have yet to be determined. The aim of the current study was to identify the mechanism(s) by which the TFF1 gene is regulated in gastric carcinogenesis. In this study, TFF1 was shown to be silenced or downregulated in gastric tumor tissue compared with matched non‑cancerous tissue. In addition, human gastric cells weakly expressed TFF1. The hypermethylation status in the promoter CpG islands appeared to be correlated with TFF1 expression levels in gastric cell lines or specimen tissue. Further molecular analysis indicated that the CpG islands play a role in the promoter activity of the TFF1 gene. The expression of TFF1 and DNA methylation of its promoter affected cell proliferation and apoptosis. The expression of TFF1 in gastric cell lines was restored with a demethylating agent, 5‑azacytidine. Low expression of TFF1 in gastric cell lines and cancer tissue is associated with TP 53. In conclusion, the current study demonstrates that DNA methylation is a key mechanism of silencing TFF1 expression in human gastric cells and TFF1 gene hypermethylation of the CpG islands is a potential biomarker for GC.

Is colonoscopic screening necessary for patients with gastric adenoma or cancer?

BACKGROUND

Since colorectal adenoma or cancer is commonly associated with gastric adenoma or cancer, early colorectal adenoma detection can affect the survival of gastric adenoma or cancer patients.

AIMS

The purpose here was to investigate the colorectal adenoma or cancer prevalence and evaluate the necessity for screening colonoscopy in gastric adenoma or cancer patients.

PATIENTS AND METHODS

From September 2005 through August 2010, 857 patients younger than 70 years who had gastric adenoma or cancer were enrolled. Healthy age- and sex-matched controls were selected from the general screening population. The prevalence and risk of colorectal adenoma or cancer were compared between the participants and the controls.

RESULTS

Data from 416 patients in the gastric neoplasm group (123 with gastric adenoma and 293 with gastric cancer) and 416 healthy control group participants were included in the statistical analysis. The presence of gastric adenoma or cancer was an independent risk factor for colorectal neoplasm (OR = 1.348, 95 % CI = 1.001-1.815). Patients with diffuse type gastric cancer had a lower prevalence of colorectal adenoma or cancer than those with gastric adenoma or intestinal type cancer. In gastric cancer patients younger than 50 years, intestinal type histology was significantly associated with colorectal adenoma or cancer (OR = 3.838, 95 % CI = 1.077-13.677).

CONCLUSIONS

The colorectal adenoma or cancer risk was significantly increased in patients with gastric adenoma or cancer. Therefore, screening colonoscopy should be considered for gastric adenoma or cancer patients including young patients, in the case of intestinal type gastric cancer.

Meta-analysis: eradication of Helicobacter pylori infection is associated with the development of endoscopic gastroesophageal reflux disease

OBJECTIVE

The role of Helicobacter pylori infection in the pathogenesis of gastroesophageal reflux disease (GORD) is controversial. We aimed to confirm the negative association between H. pylori infection and endoscopic GORD and further determine whether eradication of the infection is associated with the development of endoscopic GORD.

MATERIALS AND METHODS

Case-control studies comparing the prevalence of H. pylori infection between patients with and those without GORD, type A cohort studies comparing the incidence of GORD between patients with and those without anti-H. pylori eradication therapy, and type B cohort studies comparing the incidence of GORD between H. pylori-positive patients with and those without successful eradication were included. Moreover, the effects of H. pylori eradication on the development of GORD in randomized-controlled trials were also analyzed.

RESULTS

Overall, 43 studies were analyzed. Case-control studies showed a lower prevalence of H. pylori infection in patients with GORD [odds ratio 0.64, 95% confidence interval (CI) 0.49-0.83]. Type A cohort studies showed an increased incidence of GORD in patients whose H. pylori infection was successfully eradicated [risk ratio (RR) 2.50, 95% CI 1.46-4.26]. Type B cohort studies showed that patients whose H. pylori had been eradicated had a higher risk of GORD (RR 1.70, 95% CI 1.30-2.23). Moreover, randomized-controlled trials showed that H. pylori eradication leads to a higher risk of GORD (RR 1.99, 95% CI 1.23-3.22); subanalyses showed that the risk existed especially in Asian studies (RR 4.53, 95% CI 1.66-12.36).

CONCLUSION

H. pylori infection shows a negative association with the development of endoscopic GORD. Eradication of the infection may be a risk factor for de-novo endoscopic GORD, especially in Asian populations.

Association study of single nucleotide polymorphisms in XRCC1 gene with the risk of gastric cancer in Chinese population

Gastric cancer is one of highly cancer-related deaths in the world. Previous evidence suggests that the X-ray repair cross-complementing group 1 gene (XRCC1) is one of the most important candidate genes for influencing gastric cancer risk. The objective of this study was to detect the potential association of genetic variants in XRCC1 gene with gastric cancer risk in Chinese Han population. In total, we enrolled 395 gastric cancer patients and 398 cancer-free controls in this study. The genotyping of c.910A>G and c.1804C>A genetic variants in XRCC1 gene were investigate by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and created restriction site-PCR (CRS-PCR) methods, respectively. We found the genotypes/alleles from these two genetic variants were statistically associated with the increased risk of gastric cancer (for c.910A>G, GG versus (vs.) AA: OR = 2.00, 95% CI 1.21-3.31; AG vs. AA: OR = 1.50, 95% CI 1.12-2.02; GG/AG vs. AA: OR = 1.59, 95% CI 1.20-2.10; GG vs.

AG/AA

OR = 1.68, 95% CI 1.03-2.73; G vs. A: OR = 1.47, 95% CI 1.18-1.83; for c.1804C>A, AA vs. CC: OR = 2.68, 95% CI 1.46-4.94; AA vs.

CA/CC

OR = 2.62, 95% CI 1.44-4.76; A vs. C: OR = 1.33, 95% CI 1.06-1.66). The allele-G of c.910A>G and allele-A of c.1804C>A genetic variants may contribute to gastric cancer susceptibility. These preliminary results indicate that these XRCC1 genetic variants are potentially related to gastric cancer susceptibility in Chinese Han population, and might be used as molecular markers.

Genetic polymorphisms of XRCC1 gene and susceptibility to gastric cancer in Chinese Han population

This study aims to evaluate whether the c.1471G > A and c.1686C > G genetic polymorphisms of XRCC1 gene influencing gastric cancer susceptibility. A total of 813 subjects with Chinese Han ethnicity were enrolled. Our data suggest that the allele and genotype frequencies are significantly different from gastric cancer patients with cancer-free controls. We find that c.1471G > A and c.1686C > G genetic polymorphisms statistically increase the risk of gastric cancer. Our findings indicate these two genetic polymorphisms are related with the susceptibility to gastric cancer, and could be used as molecular markers for detecting gastric cancer in Chinese Han ethnicity.

Association between single genetic polymorphisms of MDR1 gene and gastric cancer susceptibility in Chinese

Gastric cancer is a common cancer worldwide. The multidrug resistance 1 gene (MDR1) is one of the most important candidate genes for influencing gastric cancer susceptibility. This study aimed to analyze the association between genetic variants of MDR1 gene and the susceptibility to gastric cancer in Chinese Han population. A total of 365 gastric cancer patients and 367 cancer-free controls were enrolled in this study. The single genetic polymorphisms (SNPs) of MDR1 gene were genotyped by the created restriction site-polymerase chain reaction method. Our data suggested that the allele and genotype frequencies of c.159G > T and c.1564A > T were statistically different between gastric cancer patients and cancer-free controls. Association analyses indicated that these two SNPs were statistically associated with the increased risk of gastric cancer (for c.159G > T, TT versus (vs.) GG: OR 2.34, 95 % CI 1.31-4.19; TT vs.

GT/GG

OR 2.32, 95 % CI 1.32-4.08; T vs. G: OR 1.27, 95 % CI 1.01-1.59; for c.1564A > T, TT vs. AA: OR 2.27, 95 % CI 1.31-3.93; TT vs.

AT/AA

OR 2.21, 95 % CI 1.30-3.75; T vs. A: OR 1.30, 95 % CI 1.04-1.62). The allele-T of both these two SNPs may contribute to the susceptibility to gastric cancer in Chinese Han population. The c.159G > T and c.1564A > T genetic variants might be used as molecular markers for detecting gastric cancer susceptibility.

siRNA interference with a proliferation-inducing ligand gene in the Sgr-7901 gastric carcinoma cell line

OBJECTIVE

The present study aimed to investigate the influence of siRNA interference with a proliferation- inducing ligand (APRIL) gene on gastric carcinoma sgr-7901 cell apoptosis. Correlations between APRIL silencing and tyrosine kinase (trka) expression were also explored.

METHODS

Two APRIL-silencing siRNA vectors were constructed, and transfected into human gastric carcinoma sgr-7901 cells, expression before and after transfection being detected using RT-PCR and western blot analyses. The expression of 15 trka genes was detected using RT- PCR and apoptotic rates of sgr-7901 were assessed by flow cytometry.

RESULTS

The expression levels of receptor trka genes were significantly decreased, and the apoptotic rate of sgr-7901 was significantly increased after transfection (P < 0.05).

CONCLUSION

APRIL gene silencing can increase the apoptotic rate of gastric carcinoma cells, and inhibit the expression of receptor trka genes. There is a correlation between the signaling pathways of APRIL and trka.

No association between IL-1β -31 C/T polymorphism and the risk of duodenal ulcer: a meta-analysis of 3793 subjects

The aim of this study was to perform a meta-analysis to investigate a more authentic association between IL-1β -31 C/T polymorphism and duodenal ulcer (DU). Systematic searches of electronic databases Embase, PubMed and Web of Science were performed. Study selection, data abstraction and study quality evaluation were independently conducted in duplicate. Statistical analyses were conducted using software Stata 11.0. The pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were applied. Publication bias was tested by Begg's funnel plot and Egger's regression test. A total of 12 studies including 1151 cases and 2642 controls were included in our final meta-analysis. There was no evidence of significant association between IL-1β -31 C/T polymorphism and DU (allelic model: OR=0.96, 95%CI=0.86-1.07; additive model: OR=0.85, 95%CI=0.67-1.07; dominant model: OR=0.95, 95%CI=0.81-1.13; and recessive model: OR=0.95, 95%CI=0.79-1.15). Significant association was found in additive model for PB subgroup (OR=0.65, 95%CI=0.44-0.96) and recessive model for non-Asian subgroup (OR=0.72, 95%CI=0.52-0.99). In conclusion, our meta-analysis suggested that there was no evidence of significant association between IL-1β -31 C/T polymorphism and DU with or without Helicobacter pylori infection in overall population, whereas significant association was found by subgroup analyses which showed protective effect of C/C genotype against DU risk.

The relationship between Helicobacter pylori infection and the effects of chemotherapy in patients with advanced or metastatic gastric cancer

PURPOSE

Several reports have shown a better prognosis in gastric cancer patients who are positive for Helicobacter pylori (HP) infection compared with negative cases. However, there are currently no studies that investigate the relationship between HP infection and the effects of chemotherapy in gastric cancer patients. In this study, we report the relationship between HP infection and chemotherapy effects in patients with advanced or metastatic gastric cancer.

METHODS

Sixty-one patients with advanced or metastatic gastric cancer were enrolled in this study. Biopsies were conducted around the tumor site to determine HP status. Patients were then treated with combination 5-FU and cisplatin-based chemotherapy. And we compared chemotherapy response rate and overall survival rate between HP infection group and without HP infection group.

RESULTS

Twelve of 18 patients with HP infection (66.7 %) and 9 of 42 patients without HP infection (21.4 %) showed a partial response to chemotherapy (Chi square P = 0.001). Patients with HP infection had a median survival time of 13 months (95 % CI, 6.9-19.1 months), which was significantly longer than that of patients without HP infection (9 months; P = 0.027, log-rank test).

CONCLUSIONS

Patients with advanced or metastatic gastric cancer with concomitant HP infection had a better response to chemotherapy and had an improved overall prognosis compared with patients without HP infection. Further studies are warranted to confirm these findings.

Meta-analysis of the association of CYP1A1 polymorphisms with gastric cancer susceptibility and interaction with tobacco smoking

The association of two cytochrome P4501A1 (CYP1A1) polymorphisms, m1 (T6235C transition) and m2 (A4889G transition), with gastric cancer risk is inconclusive. We conducted a meta-analysis of all available studies to evaluate the potential role of the polymorphisms and their interactions with tobacco smoking in gastric cancer susceptibility. Published literature from PubMed was retrieved by two investigators independently. Fourteen case-control studies with 2,032 gastric cancer cases and 5,099 controls were selected. A fixed effects model or a random-effects model was used to estimate the odds ratio (OR) for the CYP1A1 polymorphisms and the occurrence of gastric cancer. Significant associations between CYP1A1 m1 and m2 polymorphisms and gastric cancer susceptibility were not observed in all genetic models in the overall analyses. Subgroup analyses by ethnicity and source of controls did not reveal significant associations with gastric cancer risk. Stratification analysis by smoking status found that carriers of the heterozygous and homozygous m1 genotypes decreased the susceptibility of gastric cancer among ever-smokers (pooled OR = 0.56, 95 % CI 0.36-0.89, fixed effects). In contrast, the m2 genotypes (G/G and A/G) did not show any relevance to gastric cancer risk among the smoking population (pooled OR = 1.30, 95 % CI 0.84-2.00, fixed effects). Overall, we found that the CYP1A1 polymorphism itself, either m1 or m2, did not represent an independent genetic risk factor influencing gastric cancer. However, subgroup analyses suggest that carriers of the heterozygous and homozygous m1 genotype who are exposed to tobacco smoke have a significantly lower risk of developing gastric cancer. To explain the observed reduction of gastric cancer risk, we proposed a novel hypothesis of "observation bias". This hypothesis is also applicable to explain the combined effects of other genetic polymorphisms and environmental factors on the risk of developing cancers, and the rationality of the hypothesis needs to be further investigated.

Cancer in Pacific people in New Zealand

PURPOSE

To describe cancer incidence rates among Pacific people living in New Zealand from 1981 to 2004.

METHODS

Linked census-cancer registration data were used to calculate age-standardized cancer incidence rates for Pacific people. Both trends over time within Pacific people and differences in rates between Pacific and European/Other people in New Zealand were assessed.

RESULTS

Pacific rates were higher for cancers of the cervix, endometrium, gallbladder, lip, mouth and pharynx, liver, lung, ovary, pancreas, stomach, and thyroid, and lower for colorectal, bladder, and testicular cancers and melanoma. Differences were large, ranging from a 90 % lower rate of melanoma to over seven times higher rate of liver cancer compared to European/Other. Breast and prostate cancers were the commonest malignancies for Pacific women and men, respectively. Important changes for Pacific women over time include a 64 % decrease in cervical cancer incidence (ptrend = 0.02) and a 245 % increase for lung cancer (ptrend = 0.02), while men had a 366 % increase in prostate cancer (ptrend = 0.02).

CONCLUSIONS

Pacific people in New Zealand have a disproportionate cancer burden related to infectious diseases such as HPV and Hepatitis B. However, with escalating evidence for causal associations between diabetes, obesity, and physical inactivity with various cancers, the challenge will be to prevent these cancers from rising in Pacific people who have the highest rates of these conditions in New Zealand. Disparities for tobacco-related cancers support tobacco consumption as another important cause of cancer incidence disparity. Continued efforts are needed to reduce infectious disease and improve screening program uptake among Pacific people.

NNK enhances cell migration through α7-nicotinic acetylcholine receptor accompanied by increased of fibronectin expression in gastric cancer

BACKGROUND

In this study, we intended to dissect the mechanism of 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-enhanced migration of gastric cancer. Smoking has been defined as a risk factor for gastric cancer. Tobacco-specific carcinogen, NNK, was reported to enhance cancer progression in gastric cancer. Currently, metastasis is the major issue for clinical cancer therapy, but the influence of NNK on the migration of gastric cancer remains to be determined.

METHODS

The expression of nicotinic receptor in gastric cancer cells was identified by real-time polymerase chain reaction and Western blotting. The influence of NNK on migration of gastric cancer cells was evaluated by the transwell migration assay system. Receptor-mediated migration was studied by both inhibitor and small interfering RNA.

RESULTS

Alpha7 nicotinic acetylcholine receptor, alpha7-nicotinic acetylcholine receptor (nAChR), was identified higher than alpha9-nAChR in gastric cancer cell lines, AGS cells. NNK enhanced significantly gastric cancer cell migration in transwell assay. We used inhibitor and siRNA to demonstrate that alpha7-nAChR mediated NNK-enhanced gastric cancer cell migration and upregulation of fibronectin were involved in NNK-enhanced migration of gastric cancer cells. Finally, we found that silenced fibronectin expression level inhibited the migratory ability in AGS cells.

CONCLUSIONS

NNK enhanced gastric cancer metastasis through alpha7-nAChR and fibronectin-one of the hallmarks of epithelial mesenchymal transition.

Association of mtDNA D-loop polymorphisms with risk of gastric cancer in Chinese population

The aim of present study was to evaluate the association of common polymorphisms detected in mitochondrial DNA (mtDNA) D-loop region (mononucleotide repetitive D310, single nucleotide polymorphism (SNP) D16521) with susceptibility to gastric cancer (GC) in northwestern Chinese population. A total of 180 GC patients and 218 healthy controls were investigated by using PCR- denaturing high performance liquid chromatography (DHPLC) assay. Genotype and allele distributions and haplotype construction were analyzed in case-control study. We found D310 and D16521 heteroplasmy were significantly different between GC cases and controls (p < 0.05), and D16521 homoplasmy showed association with histological grade of GC (p < 0.05). Haplotype 7C/T, 8C/C and 9C/C had significant association with GC risk implied from analysis of D310 and D16521. Taken together, these findings suggested that mtDNA D-Loop polymorphisms and haplotypes may contribute to genetic susceptibility to GC in Chinese population.

Activation of epidermal growth factor receptor signaling by the prostaglandin E(2) receptor EP4 pathway during gastric tumorigenesis

Cyclooxygenase-2 (COX-2) plays an important role in tumorigenesis through prostaglandin E(2) (PGE(2)) biosynthesis. It has been shown by in vitro studies that PGE(2) signaling transactivates epidermal growth factor receptor (EGFR) through an intracellular mechanism. However, the mechanisms underlying PGE(2)-induced EGFR activation in in vivo tumors are still not fully understood. We previously constructed transgenic mice that develop gastric tumors caused by oncogenic activation and PGE(2) pathway induction. Importantly, expression of EGFR ligands, epiregulin, amphiregulin, heparin-binding EGF-like growth factor, and betacellulin, as well as a disintegrin and metalloproteinases (ADAMs), ADAM8, ADAM9, ADAM10, and ADAM17 were significantly increased in the mouse gastric tumors in a PGE(2) pathway-dependent manner. These ADAMs can activate EGFR by ectodomain shedding of EGFR ligands. Notably, the extensive induction of EGFR ligands and ADAMs was suppressed by inhibition of the PGE(2) receptor EP4. Moreover, EP4 signaling induced expression of amphiregulin and epiregulin in activated macrophages, whereas EP4 pathway was required for basal expression of epiregulin in gastric epithelial cells. In contrast, ADAMs were not induced directly by PGE(2) in these cells, suggesting indirect mechanism possibly through PGE(2)-associated inflammatory responses. These results suggest that PGE(2) signaling through EP4 activates EGFR in gastric tumors through global induction of EGFR ligands and ADAMs in several cell types either by direct or indirect mechanism. Importantly, gastric tumorigenesis of the transgenic mice was significantly suppressed by combination treatment with EGFR and COX-2 inhibitors. Therefore, it is possible that inhibition of both COX-2/PGE(2) and EGFR pathways represents an effective strategy for preventing gastric cancer.

In situ spectral imaging of marker proteins in gastric cancer with near-infrared and visible quantum dots probes

This study presents the investigation of bioconjugating ability of near-infrared (NIR) CdSeTe/ZnS quantum dots (QDs) (710 nm) and visible CdSe QDs (595 nm) in immunofluorescent staining for cancer biomarkers in gastric cancer tissues probed with the homemade Hadamard transform (HT) spectral imaging microscope and a commercial multispectral imaging system. The results show that imunostaining ability of NIR QDs probes is stronger than that of visible QDs when the two kinds of QDs are simultaneously used to probe the cancer biomarkers such as cytokeratin 20 (CK20) and proliferating cell nuclear antigen (PCNA) in gastric cancer tissues. Moreover, when the two QDs probes are used for immunostaining successively for the same target molecules, staining order has great influences on the final results due to their different conjugating ability to the marker proteins. The results imply that NIR QDs hold more promise for real-time imaging of tumor tissues due to its higher sensitivity and contrast. In addition, the results also demonstrate the potential of Hadamard transform spectral imaging as a useful tool in biomedical analysis and quantitative evaluation for tumor tissues.

Over-expression of Ephb4 is associated with carcinogenesis of gastric cancer

BACKGROUND

Gastric cancer is one of the most frequently diagnosed malignancies in the world. The gene expression profile and molecular grouping of gastric cancer has been a challenging task due to its inherent complexity and variation among individuals.

AIMS

To determine the molecular mechanism associated with gastric carcinogenesis.

METHODS

We analyzed the gene expression profiles of 20 cancerous tissues and their tumor-adjacent tissue from patients with gastric cancer by using a 14 K cDNA microarray. The differentially expressed genes and their products were verified by semiquantitative reverse transcription PCR (RT-PCR), western blotting and immunohistochemistry of gastric cancer and normal tissue samples.

RESULTS

A total of 69 genes were found to be differentially regulated in the cancerous tissue. Among them, genes such as CDH17, ETV4, S100A6, S100A11, Ephb4, and KLK10 were confirmed by RT-PCR to be up-regulated, while genes such as NK4 and PPP2R1B were down-regulated. Western blotting and immunohistochemistry indicated that Ephb4 was over-expressed and localized to the cytoplasm of gastric cancer cells. Moreover, Ephb4 protein was observed as being significantly related to tumor size and pN category (p = 0.001 and 0.007, respectively).

CONCLUSIONS

These newly identified genes might provide a valuable resource for understanding the molecular mechanism associated with the carcinogenesis of gastric cancer and for finding potential diagnostic markers of gastric cancer.