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

Helicobacter pylori and Epstein-Barr Virus Co-Infection in Gastric Disease: What Is the Correlation with p53 Mutation, Genes Methylation and Microsatellite Instability in a Cohort of Sicilian Population?

Genetic predisposition, environmental factors, and infectious agents interact in the development of gastric diseases. Helicobacter pylori (Hp) and Epstein-Barr virus (EBV) infection has recently been shown to be correlated with these diseases. A cross-sectional study was performed on 100 hospitalized Italian patients with and without gastric diseases. The patients were stratified into four groups. Significant methylation status differences among CDH1, DAPK, COX2, hMLH1 and CDKN2A were observed for coinfected (Hp-EBV group) patients; particularly, a significant presence of COX2 (p = 0.0179) was observed. For microsatellite instability, minor stability was described in the Hp-HBV group (69.23%, p = 0.0456). Finally, for p53 mutation in the EBV group, exon 6 was, significantly, most frequent in comparison to others (p = 0.0124), and in the Hp-EBV group exon 8 was, significantly, most frequent in comparison to others (p < 0.0001). A significant positive relationship was found between patients with infection (Hp, EBV or both) and p53 mutation (rho = 0.383, p = 0.0001), methylation status (rho = 0.432, p < 0.0001) and microsatellite instability (rho = 0.285, p = 0.004). Finally, we observed among infection and methylation status, microsatellite instability, and p53 mutation a significant positive relationship only between infection and methylation status (OR = 3.78, p = 0.0075) and infection and p53 mutation (OR = 6.21, p = 0.0082). According to our analysis, gastric disease in the Sicilian population has different pathways depending on the presence of various factors, including infectious agents such as Hp and EBV and genetic factors of the subject.

Trends in the Performance of the Korean National Cancer Screening Program for Gastric Cancer from 2007 to 2016

Purpose

The Korean National Cancer Screening Program (KNCSP) has implemented two screening methods for gastric cancer— upper gastrointestinal series (UGIS) and endoscopy—for Koreans aged ≥ 40 years. We aimed to assess performance trends for both screening methods.

Materials and Methods

The KNCSP database was used to evaluate individuals who underwent screening from 2007 to 2016. The final gastric cancer diagnosis was ascertained by linking with the Korean Central Cancer Registry. We conducted a prospective, cross-sectional analysis to estimate performance indicators of gastric cancer screening by UGIS and endoscopy, stratified by sociodemographic factors.

Results

We found that screening rates for gastric cancer increased from 28% to 51.7% between 2007 and 2016, and that the rate of endoscopy use for gastric cancer screening increased sharply. Cancer detection rates (CDR) of UGIS and endoscopy were 0.41 and 2.25 per 1,000 screens in 2007–2008 and 0.26 and 1.99 in 2015–2016, respectively. Interval cancer rates (ICR) per 1,000 negative screenings were 1.33 (2007–2008) and 1.21 (2015–2016) for UGIS and 1.14 (2007–2008) and 0.88 (2015–2016) for endoscopy. The sensitivity of UGIS decreased from 23.6% (2007–2008) to 17.6% (2015–2016), whereas that of endoscopy increased from 66.4% (2007–2008) to 69.3% (2015–2016). Specificity was maintained at > 99% for both methods over the study period.

Conclusion

The use of endoscopy for gastric cancer screening within the KNCSP has increased. Endoscopy has higher CDR, sensitivity, and specificity, and lower ICR estimates than does UGIS.

Development of Helicobacter pylori Whole-Proteome Arrays and Identification of Serologic Biomarkers for Noncardia Gastric Cancer in the MCC-Spain Study

BACKGROUND

Helicobacter pylori (H. pylori) is a bacterial carcinogen and the leading risk factor for noncardia gastric cancer (NCGC). Detecting antibodies against specific H. pylori proteins in peripheral blood can be applied to characterize infection and determine disease associations. Most studies analyzing the association between H. pylori infection and gastric cancer have focused on previously identified antigens, predominantly the virulence factor cytotoxin-associated gene A (CagA). Selecting antigens in an unbiased approach may, however, allow the identification of novel biomarkers.

METHODS

Using a combination of multiple spotting technique and cell-free, on-chip protein expression, we displayed the H. pylori genome (strain 26695) on high-density microarrays. Immunogenic proteins were identified by serum pool incubations and henceforth analyzed in individual samples. To test its applicability, we used sera from a multicase-control (MCC)-Spain study. Serologic responses between NCGC cases and controls were assessed by conditional logistic regression estimating ORs and 95% confidence intervals.

RESULTS

We successfully expressed 93% of the 1,440 H. pylori open reading frames in situ. Of these, 231 (17%) were found to be immunogenic. By comparing 58 NCGC cases with 58 matched controls, we confirmed a higher seroprevalence of CagA among cases (66%) than controls (31%). We further identified a potential novel marker, the Helicobacter outer membrane protein A (HopA).

CONCLUSIONS

In this study, we provide evidence that our H. pylori whole-proteome microarray offers a platform for unbiased de novo identification of serologic biomarkers.

IMPACT

Given its versatile workflow, antibody responses against other H. pylori strains and possible associations with diverse H. pylori-related outcomes can be systematically analyzed.

High-Throughput Sequencing of Gastric Cancer Patients: Unravelling Genetic Predispositions Towards an Early-Onset Subtype

Background: Gastric cancer is the fourth most common cause of cancer-related death. Currently, it is broadly accepted that the molecular complexity and heterogeneity of gastric cancer, both inter- and intra-tumor, display important barriers for finding specific biomarkers for the early detection and diagnosis of this malignancy. Early-onset gastric cancer is not as prevalent as conventional gastric carcinoma, but it is a preferable model for studying the genetic background, as young patients are less exposed to environmental factors, which influence cancer development. Aim: The main objective of this study was to reveal age-dependent genotypic characteristics of gastric cancer subtypes, as well as conduct mutation profiling for the most frequent alterations in gastric cancer development, using targeted next-generation sequencing technology. Patients and methods: The study group included 53 patients, consisting of 18 patients with conventional gastric cancer and 35 with an early-onset subtype. The DNA of all index cases was used for next-generation sequencing, employing a panel of 94 genes and 284 single nucleotide polymorphisms (SNPs) (TruSight Cancer Panel, Illumina), which is characteristic for common and rare types of cancer. Results: From among the 53 samples processed for sequencing, we were able to identify seven candidate genes (STK11, RET, FANCM, SLX4, WRN, MEN1, and KIT) and nine variants among them: one splice_acceptor, four synonymous, and four missense variants. These were selected for the age-dependent differentiation of gastric cancer subtypes. We found four variants with C-Score ≥ 10, as 10% of the most deleterious substitutions: rs1800862 (RET), rs10138997 (FANCM), rs2230009 (WRN), and rs2959656 (MEN1). We identified 36 different variants, among 24 different genes, which were the most frequent genetic alterations among study subjects. We found 16 different variants among the genes that were present in 100% of the total cohort: SDHB (rs2746462), ALK (rs1670283), XPC (rs2958057), RECQL4 (rs4925828; rs11342077, rs398010167; rs2721190), DDB2 (rs326212), MEN1 (rs540012), AIP (rs4930199), ATM (rs659243), HNF1A (rs1169305), BRCA2 (rs206075; rs169547), ERCC5 (rs9514066; rs9514067), and FANCI (rs7183618). Conclusions: The technology of next-generation sequencing is a useful tool for studying the development and progression of gastric carcinoma in a high-throughput way. Our study revealed that early-onset gastric cancer has a different mutation frequency profile in certain genes compared to conventional subtype.

Nutritional Factors Involved in the Etiology of Gastric Cancer: A Systematic Review

CONTEXT

Since treatment options for GC are limited, the best and most effective way is to try to reduce the incidences and understanding prevention strategies.

OBJECTIVE

The success in prevention strategies depends on understanding etiologic mechanisms. Our goal is to identify the major nutritional risk factors for GC, and we will examine the controversial evidence.

DATA SOURCES

We used Pub Med, Google Scholar, Scopus, Science Direct, Elsevier, Springer, and MEDLINE databases for extracting articles.

DATA EXTRACTION

Human studies published in English from 1997to2018 were included. Two reviewers other than authors initially assessed abstract of 742 papers and 248papers were selected for future assessments. After full review and consideration of the inclusion and exclusion criteria, we used 85 articles.

RESULTS

Dietary salt is a strong independent risk for GC whereas alcohol is most likely a risk only in the presence of heavy alcohol consumption. Red meat and high-fat diet increase the risk of developing GC but fresh fruits, vegetables and certain micronutrients like selenium and vitamin C are protective.

CONCLUSION

Some nutrients such as selenium, vitamin C, folate, iron, and zinc are involved in the etiology of GC. On the other hand; salt, fats, alcohol, red meat, and pepper were reported to be risk factors for GC. Since the GC is a heterogeneous malignancy and multiple factors are involved in its genesis.

Correlation between prognostic nutritional index and occlusal status in gastric cancer

OBJECTIVE

Systemic inflammatory responses in cancer patients are important factors for nutrition and prognosis. This study evaluates the association between tooth loss, occlusal status, and prognostic nutritional index (PNI).

METHODS

A total of 93 patients with gastric cancer were included. These parameters were investigated the following: stage, body mass index (BMI), total lymphocyte count, C-reactive protein (CRP), PNI, and albumin (ALB). Patients were divided into three groups by Eichner classification (group A had contact in four support zones; group B had in one to three zones or in anterior region; and group C had no contact). PNI assumed 40 or less undernutrition. Multiple regression analysis was performed (PNI, dependent variable; Eichner index, main independent variable), using four independent variables (sex, age, BMI, and CRP) as adjustment factors.

RESULTS

The mean ± SD PNI in groups A, B, and C was 43.0 ± 4.7, 41.7 ± 5.2, and 36.7 ± 7.7, respectively. A significant positive correlation was found between the number of teeth, both ALB, and PNI. ALB and PNI differed significantly between groups A and C (ALB, p = .0003; PNI, p = .005).

CONCLUSION

We recommend a preoperative dental evaluation for assessing the nutritional status of patients with gastric cancer.

Looking at cancer health disparities without the colored lenses

Cancer health disparities (CHDs), defined as the adverse differences in cancer incidence and mortality, are prevalent in certain racial and ethnic groups. Underlying causes of CHDs are multi-factorial and debatable. While low socioeconomic status, geographical location, lifestyle and behavioral factors are mostly believed to contribute to CHDs, regardless of ethnic and racial background, significant data now also exist to support a genetic basis of such disparities as well. Clearly, CHDs could best be understood by studying the interplay of multiple (genetic and non-genetic) factors and then translating the resulting knowledge into effective approaches for reducing the existing disparity gaps. This review article highlights these aspects in brief and calls the people of different expertise to work together to make an impact and tackle the challenges associated with CHDs.

Pectolinarigenin Induced Cell Cycle Arrest, Autophagy, and Apoptosis in Gastric Cancer Cell via PI3K/AKT/mTOR Signaling Pathway

Pectolinarigenin (PEC), a natural flavonoid present in Cirsium chanroenicum and in some species of Citrus fruits, has various pharmacological benefits such as anti-inflammatory and anti-cancer activities. In the present study, we investigated the anti-cancer mechanism of PEC induced cell death caused by autophagy and apoptosis in AGS and MKN28 human gastric cancer cells. The PEC treatment significantly inhibited the AGS and MKN28 cell growth in a dose-dependent manner. Further, PEC significantly elevated sub-G1 phase in AGS cells and G2/M phase cell cycle arrest in both AGS and MKN28 cells. Apoptosis was confirmed by Annexin V and Hoechst 33342 fluorescent staining. Moreover, Immunoblotting results revealed that PEC treatment down-regulated the inhibitor of apoptosis protein (IAP) family protein XIAP that leads to the activation of caspase-3 thereby cleavage of PARP (poly-ADP-ribose polymerase) in both AGS and MKN28 cells in a dose-dependent manner. The autophagy-inducing effect was indicated by the increased formation of acidic vesicular organelles (AVOs) and increased protein levels of LC3-II conversion in both AGS and MKN28 cells. PEC shows the down regulation of PI3K/AKT/mTOR pathway which is a major regulator of autophagic and apoptotic cell death in cancer cells that leads to the down-regulation of p-4EBP1, p-p70S6K, and p-eIF4E in PEC treated cells when compared with the untreated cells. In conclusion, PEC treatment might have anti-cancer effect by down-regulation of PI3K/AKT/mTOR pathway leading to G2/M phase cell cycle arrest, autophagic and apoptotic cell death in human gastric cancer cells. Further studies of PEC treatment can support to develop as a potential alternative therapeutic agent for human gastric carcinoma.

CD147 overexpression may serve as a promising diagnostic and prognostic marker for gastric cancer: evidence from original research and literature

Gastric cancer (GC) is one of the most common malignancies worldwide. The expression of CD147 protein is associated with GC. However, the clinical role of CD147 in GC has not been investigated extensively. Hence, we focused on studying the association between the expression of CD147 and clinicopathological features of GC patients in this study. Firstly, sixteen publications (1752 cases and 391 controls) and one from our own original research (143 cases) were included in the meta-analysis to obtain a more precise estimation of the diagnostic value of CD147. The results showed that expression rate of CD147 in the GC group is higher than that in control group. Moreover, gender, TNM stage, lymph node metastasis, and depth of invasion are all associated with CD147. Further, sections of gastric tissue from 143 cases underwent immunohistochemical staining for evaluation of CD147 protein expression. Our retrospective analysis demonstrated CD147 protein expression was significantly associated with clinical N stage, and tumor stage. Meanwhile, it can also serve as an independent prognosis biomarker. In conclusion, our results support the role of CD147 as a good indicator of diagnosis and prognosis.

Stomach Cancer Disparity among Korean Americans by Tumor Characteristics: Comparison with Non-Hispanic Whites, Japanese Americans, South Koreans, and Japanese

Background: Stomach cancer incidence shows substantial racial-ethnic disparity in the United States, with Korean Americans experiencing by far the highest incidence. We examined stomach cancer incidence trends in Korean Americans by tumor subsite, histology, and stage and compared them with incidence rates in racial-ethnic groups with the second highest rate (Japanese Americans) and the lowest rate (non-Hispanic whites; NHWs) as well as populations in South Korea and Japan.Methods: We calculated age-adjusted incidence rates by racial-ethnic groups, sex, and tumor characteristics, using the 1988-2012 California Cancer Registry data. Data on South Korea and Japan were obtained from the literature and other resources.Results: Between 1988 and 2012 in California, Korean Americans had about five times greater incidence than NHWs and twice that of Japanese Americans. Tumor characteristics differed by ethnic group and gender. The incidence in Korean Americans has declined during recent years, for both cardia and noncardia sites and for both intestinal- and diffuse-type histology. Although Korean Americans were diagnosed at an earlier stage than other Californians, the proportion with localized disease (43%) was much smaller than in South Korea (57%), where population-based screening is available.Conclusions: Stomach cancer incidence declined in the highest risk ethnic groups. However, the persistent disparity between Korean Americans and other racial-ethnic groups warrants additional strategies for prevention and earlier diagnosis.Impact: Analysis of California Cancer Registry data identified a racial-ethnic subgroup with stomach cancer disparity that may benefit from targeted prevention and screening efforts. Cancer Epidemiol Biomarkers Prev; 26(4); 587-96. ©2016 AACR.

Da0324, an inhibitor of nuclear factor-κB activation, demonstrates selective antitumor activity on human gastric cancer cells

Background

The transcription factor nuclear factor-κB (NF-κB) is constitutively activated in a variety of human cancers, including gastric cancer. NF-κB inhibitors that selectively kill cancer cells are urgently needed for cancer treatment. Curcumin is a potent inhibitor of NF-κB activation. Unfortunately, the therapeutic potential of curcumin is limited by its relatively low potency and poor cellular bioavailability. In this study, we presented a novel NF-κB inhibitor named Da0324, a synthetic asymmetric mono-carbonyl analog of curcumin. The purpose of this study is to research the expression of NF-κB in gastric cancer and the antitumor activity and mechanism of Da0324 on human gastric cancer cells.

Methods

The expressions between gastric cancer tissues/cells and normal gastric tissues/cells of NF-κB were evaluated by Western blot. The inhibition viability of compounds on human gastric cancer cell lines SGC-7901, BGC-823, MGC-803, and normal gastric mucosa epithelial cell line GES-1 was assessed with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Absorption spectrum method and high-performance liquid chromatography method detected the stability of the compound in vitro. The compound-induced changes of inducible NF-κB activation in the SGC-7901 and BGC-823 cells were examined by Western blot analysis and immunofluorescence methods. The antitumor activity of compound was performed by clonogenic assay, matrigel invasion assay, flow cytometric analysis, Western blot analysis, and Hoechst 33258 staining assay.

Results

High levels of p65 were found in gastric cancer tissues and cells. Da0324 displayed higher growth inhibition against several types of gastric cancer cell lines and showed relatively low toxicity to GES-1. Moreover, Da0324 was more stable than curcumin in vitro. Western blot analysis and immunofluorescence methods showed that Da0324 blocked NF-κB activation. In addition, Da0324 significantly inhibited tumor proliferation and invasion, arrested the cell cycle, and induced apoptosis in vitro.

Conclusion

The asymmetric mono-carbonyl analog of curcumin Da0324 exhibited significantly improved antigastric cancer activity. Da0324 may be a promising NF-κB inhibitor for the selective targeting of cancer cells. However, further studies are needed in animals to validate these findings for the therapeutic use of Da0324.

Association between Tooth Loss and Gastric Cancer: A Meta-Analysis of Observational Studies

Observational studies showed that tooth loss is associated with gastric cancer, but the findings are inconsistent. In this study, a meta-analysis was conducted to evaluate the relationship between tooth loss and gastric cancer. Relevant studies were screened in PubMed and Embase databases, and nine observational studies were considered eligible for the analysis. The combined relative risks for the highest versus the lowest categories of tooth loss were 1.86 (95% CI: 1.08–3.21) and 1.31 (95% CI: 1.12–1.53) in case control and cohort studies, respectively. However, unstable results were observed in the stratified and sensitivity analysis. The current evidence, based solely on four case-control studies and five cohort studies, suggested that tooth loss is a potential marker of gastric cancer. However, we can not concluded at this time that tooth loss may be a risk factor for gastric cancer due to significant heterogeneity among studies and mixed results between case-control studies and cohort studies. Additional large-scale and high-quality prospective studies are required to evaluate the association between tooth loss and risk of gastric cancer.

Histopathologic characteristics of gastric adenocarcinoma in Mexican patients: a 10-year experience at the Hospital Juárez of Mexico

BACKGROUND

Gastric cancer is the second cause of death by cancer worldwide. Histologic classification may predict tumor biology, clinical behavior, and outcome. According to the Lauren classification, the disease is divided into 2 types, diffuse and intestinal, and the latter has a better prognosis.

AIM

To determine the frequency of gastric adenocarcinoma and compare the histopathologic characteristics of intestinal and diffuse-type gastric adenocarcinoma in Mexican patients treated at a tertiary referral hospital.

METHODOLOGY

A retrospective study evaluated the pathology reports of patients with gastric adenocarcinoma corresponding to the time frame of January 2003 to December 2012. Adenocarcinomas of the gastric cardia were excluded. Frequencies were expressed as percentages and the categorical variables were compared with the chi-square test. Statistical significance was set at a P<.05.

RESULTS

A total of 417 cases of gastric adenocarcinoma were found, 230 (55.2%) of which were diffuse-type and 118 (28.2%) were intestinal-type. The mean age of the patients with diffuse type gastric cancer was 54.02±14.93 and 119 (51.3%) of those patients were men. The mean age of the patients with intestinal-type gastric cancer was 63.43±13.78, and 69 (62.2%) were men. Ninety-two of the diffuse-type patients were under the age of 50 years, compared with 22 of the patients with intestinal-type carcinoma.

CONCLUSIONS

This is the first study on the Mexican population to analyze the differences in the histologic types of adenocarcinoma. Diffuse-type gastric carcinoma was the most frequent subtype in our study population and it is associated with worse outcome.

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.

Dietary Factors in Relation to Helicobacter pylori Infection

Background and Aim. Helicobacter pylori (HP) and diet are both risk factors for gastric cancer. The aim of this study was to evaluate the Helicobacter pylori infection and dietary habits common in Khuzestan province. Methods. This cross-sectional study was conducted in 2011–2013 on 374 patients. Participants were interviewed using a food frequency questionnaire and tissue sample of the antrum was sent for pathology lab. The histopathological major variables were graded on a scale of 3 (mild, moderate, and severe) and data analyzed using nonparametric tests. Results. In this study, of 160 patients (43%) that were determined, 8.1 percent had severe contamination. Among dietary patterns, relationship between energy intake and carbohydrate with H. pylori was significant. A direct association was found between mean daily intakes of sausage (P = 0.001) and burgers (P < 0.05) with HP infection. Low intake of fresh vegetables and fruits was the most significant risk factors (P < 0.05). Conclusion. There is a possibility that some dietary factors such as consumption of fast foods and low intake of fresh vegetables may increase the chance of HP and severity of this infection.

Virulence Factors of Helicobacter pylori: A Review

Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa, a condition that affects the relative risk of developing various clinical disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. H. pylori presents a high-level of genetic diversity, which can be an important factor in its adaptation to the host stomach and also for the clinical outcome of infection. There are important H. pylori virulence factors that, along with host characteristics and the external environment, have been associated with the different occurrences of diseases. This review is aimed to analyzing and summarizing the main of them and possible associations with the clinical outcome.

Card15 mutations and gastric cancer in a Portuguese population

BACKGROUND. CARD15 is involved in the innate immune response and mutations of this gene have been linked with increased risk of Crohn's disease and colorectal cancer. The relation between CARD15 mutations and gastric cancer (GC) remains controversial. AIMS. To assess whether CARD15 mutations are risk factors for GC in Portugal and whether there are genotype-phenotype correlations in these patients. METHODS. The 3 main CARD15 mutations (3020insC, R702W and G908R) were searched in 150 patients with GC and in 202 healthy controls. RESULTS. Overall, CARD15 mutations were found in 28 patients (18.7%) and in 27 controls (13.4%) (p = 0.176). Individually, the incidence of 3020insC was significantly higher in patients than in controls (6.0% vs. 1.0%, p = 0.021). This polymorphism was linked with an increased risk for the intestinal-type of GC (p = 0.002), while no association was found with the diffuse and/or mixed types. Genotype frequencies for R702W (10.0% vs. 7.9%) and G908R (4.0% vs. 4.0%) were not statistically different between the two groups. Similarly, no significant associations were detected between these two polymorphisms and the different histological GC types. No correlations were observed between CARD15 mutations and family history, mean age at diagnosis or GC stage. CONCLUSIONS. The CARD15 3020insC variant is a risk factor for intestinal GC in Portugal. CARD15 variants are not correlated with age of diagnosis or family aggregation of the disease neither with the GC stage.

Association of tooth loss and oral hygiene with risk of gastric adenocarcinoma

Poor oral health and tooth loss have been proposed as possible risk factors for some chronic diseases, including gastric cancer. However, a small number of studies have tested these associations. We conducted a case-control study in Golestan Province, Iran, that enrolled 309 cases diagnosed with gastric adenocarcinoma (118 noncardia, 161 cardia, and 30 mixed-locations) and 613 sex, age, and neighborhood matched controls. Data on oral health were obtained through physical examination and questionnaire including tooth loss, the number of decayed, missing, and filled teeth, and frequency of tooth brushing. ORs and 95% confidence intervals (95% CI) were obtained using conditional logistic regression models adjusted for potential confounders. Standard one degree-of-freedom linear trend test and a multiple degree-of-freedom global test of the effect of adding oral hygiene variables to the model were also calculated. Our results showed apparent associations between tooth loss and decayed, missing, filled teeth (DMFT) score with risk of gastric cancer, overall and at each anatomic subsite. However, these associations were not monotonic and were strongly confounded by age. The results also showed that subjects who brushed their teeth less than daily were at significantly higher risk for gastric cardia adenocarcinoma ORs (95% CI) of 5.6 (1.6-19.3). We found evidence for an association between oral health and gastric cancer, but the nonmonotonic association, the relatively strong effect of confounder adjustment, and inconsistent results across studies must temper the strength of any conclusions.

Omission of breakfast and risk of gastric cancer in Mexico

AIM

To investigate factors associated with gastric cancer (GC) in the Mexican population using a validated questionnaire.

METHODS

We designed and validated in Spanish a Questionnaire to Find Factors Associated with Diseases of the Digestive Tract using GC as a model. A cross-sectional study using 49 subjects, with confirmed histopathological GC diagnosis, and 162 individuals without GC participated. Odds ratio and 95% CIs were estimated in univariate and multivariate analysis adjusted for possible confounding factors. In order to match age groups, a multivariate sub-analysis was performed in subjects ≥ 39 years of age and in females and males separately.

RESULTS

In the univariate analysis, we found an association between GC and education to primary level or below, low socioeconomic status, the use of dental prostheses, omission of breakfast, consumption of very hot food and drink, addition of salt to prepared foods, consumption of salt-preserved foods and the pattern of alcohol consumption. We found protection against GC associated with the use of mouthwash, food refrigeration and regular consumption of fruit and vegetables. In the multivariate sub-analysis with subjects of ≥ 39 years, the omission of breakfast was identified as a risk factor for GC.

CONCLUSION

Our study suggests an association between the omission of breakfast and the failure to refrigerate food with GC in the Mexican population.

Case-control study of dietary pattern and other risk factors for gastric cancer

BACKGROUND

The rates of gastric cancer reported from Ardabil Province of Iran, are among the highest in the world. The aim of this study was to investigate the risk factors for gastric cancer in Ardabil Province.

METHODS

This case-control study was conducted on 128 adults with mean age of 56.5 ± 12.8 yr old in Ardebil City, Iran in 2010 - 2011. Forty-two people with gastric cancer and 86 healthy people were recruited. Participants were interviewed using a structured questionnaire. Fasting blood samples were taken for measurement of IgG and IgA indices against Helicobacter pylori infection. Data were analyzed using the Chi-square and Independent sample t-test. 

RESULTS

Diet and H. pylori infection indices had the significant relationship with gastric cancer (P<0.05). Among dietary patterns, drinking hot tea, low intake of fresh vegetables and fruits, and unsaturated fat were the most significant risk factors (P<0.05). In gastric cancer patients, the levels of serum IgG and IgA as indicator of H. pylori infection were significantly (P<0.05) higher than the healthy subjects (IgG 37.7 ± 29.3 vs. 16.9 ± 11.1 U/ml and IgA 50.5 ± 44.7 vs. 22.9 ± 15.8 U/ml). No significant relationship was observed between tobacco smoking and alcohol consumption with gastric cancer.

CONCLUSION

Dietary pattern especially drinking hot tea and low consumption of unsaturated fat, fresh vegetables, and fruits, as well as H. pylori infection were the most important risk factors in gastric cancer patients.

Seroprevalence of Helicobacter pylori in female Vietnamese immigrants to Korea

AIM: To investigate the seroprevalence of Helicobacter pylori (H. pylori) and its relationship to nutritional factors in female Vietnamese immigrants to Korea.

METHODS: A total of 390 female immigrants from Vietnam and 206 Korean male spouses participated in the study. Blood samples from 321 female immigrants and 201 Korean male spouses were analyzed for H. pylori antibodies. Data on age, sex, alcohol consumption, smoking status, dietary nutritional factors and gastrointestinal symptoms were collected using questionnaires. The daily intakes of the following nutrients were estimated: energy, protein, niacin, lipid, fiber, calcium, iron, sodium, potassium, zinc, folate, cholesterol, and vitamins A, B1, B2, B6, C and E.

RESULTS: The prevalence of H. pylori positivity was lower in the immigrants than in age-matched Korean females (55.7% vs 71.4%, respectively; P < 0.0001) and the domestic population of Vietnam. The prevalence of H. pylori positivity among married couples was 31.7% for both spouses. There were no statistically significant differences in the incidence of smoking, amount of alcohol consumed, or nutritional factors between the H. pylori-positive and negative groups.

CONCLUSION: The prevalence of H. pylori positivity was lower among female Vietnamese immigrants than among Korean females. Nutritional factors did not differ between the H. pylori-positive and negative groups.

Ecological study for refrigerator use, salt, vegetable, and fruit intakes, and gastric cancer

We used an ecological approach to determine the correlation between vegetable, fruit and salt intakes, refrigerator use, and gastric cancer mortality in Korean population. Information on fruit and vegetable intakes per capita from the National Health and Nutrition Survey, death certificate data from the National Statistical office, refrigerator per household data from Korean Statistical Information Service, and salt/sodium intake data from a cross-sectional survey were utilized. Correlation coefficients were calculated between vegetable and fruit intakes, refrigerator per household, and gastric cancer mortality and between salt and sodium intakes, and gastric cancer mortality and incidence in the four areas. With 5, 10, and 15 years lag time, refrigerator usage and fruit intake were negatively associated with gastric cancer mortality (p < 0.01), but vegetable intake was not associated with gastric cancer mortality. When estimates of salt/sodium intake evaluated by 24-h urine collection in four areas of Korea were compared to the gastric cancer mortality and incidence in these regions, positive correlation was shown between salt/sodium intake, and gastric cancer incidence and mortality. Negative associations between refrigerator use, fruit intake, and gastric cancer mortality and positive associations between salt/sodium intake and gastric cancer mortality and incidence were suggested.

Gastric cancer in India

The incidence of gastric cancer in India is low compared to developed countries, though there are certain geographical areas (Southern part and northeastern states of country) where the incidence is comparable to high-incidence areas of world. Despite the large number of patients being treated for gastric cancer, there are not sufficient publications discussing associated risk factors and outcomes in these patients. This article discusses relevant Indian epidemiological and clinical studies about gastric cancers. This article also highlights the gap in publication from India and developed countries regarding gastric cancer and stresses on collaborative efforts of the Indian scientific community to conduct epidemiological, pathological, and clinical studies to have a new standard of care for Indian patients.

Glutamate receptor, ionotropic, kainate 2 silencing by DNA hypermethylation possesses tumor suppressor function in gastric cancer

Aberrant DNA methylation is considered a major mechanism for silencing tumor suppressor genes in gastric cancer. We used CpG microarray and differential methylation hybridization strategies to identify potential tumor suppressor genes and recovered glutamate receptor, ionotropic, kainate 2 (GRIK2) as a novel epigenetic target in gastric cancer. Additional experiments showed that the promoter region of GRIK2 was hypermethylated in 3 of the 4 tested gastric cancer cell lines, and its expression was restored by treatment of cells with the DNA methylation inhibitor, 5'-aza-dC. In clinical samples, the GRIK2 promoter was differentially hypermethylated in tumor tissues compared with adjacent normal tissues (p < 0.001), and this methylation was inversely correlated with the expression level of GRIK2 mRNA (r = -0.44). Functional studies further showed that GRIK2-expressing gastric cancer cell lines showed decreased colony formation and cell migration. Taken together, these results suggest that GRIK2 may play a tumor-suppressor role in gastric cancer. Future studies are warranted to examine whether DNA hypermethylation of the GRIK2 promoter can be used as a potential tumor marker for gastric cancer.

Characterization of tumor antigen peptide-specific T cells isolated from the neoplastic tissue of patients with gastric adenocarcinoma

Gastric cancer is a significant cause of morbidity and mortality worldwide. Surgical resection remains the primary curative treatment for gastric adenocarcinoma, but the poor (15-35%) survival rate at 5 years has prompted many studies for new therapeutic strategies, such as specific immunotherapy. The aim of this study was to analyze the functional properties of the T cell response to different antigen peptides related to gastric cancer in patients with gastric adenocarcinoma. To this purpose, we have cloned and characterized tumor-infiltrating T cells (TILs) isolated from the neoplastic gastric tissue samples. A T cell response specific to different peptides of gastric cancer antigens tested was documented in 17 out of 20 patients, selected for their HLA-A02 and/or -A24 alleles. Most of the cancer peptide-specific TILs expressed a Th1/Tc1 profile and cytotoxic activity against target cells. The effector functions of cancer peptide-specific T cells obtained from the peripheral blood of the same patients were also studied. The majority of peripheral blood peptide-specific T cells also expressed the Th1/Tc1 functional profile. In conclusion, in most of the patients with gastric adenocarcinoma, a specific type-1 T cell response to gastric cancer antigens was detectable and would have the potential of hamper tumor cell growth. However, in order to get tumor cell killing in vivo, the activity and the number of cancer peptide-specific Th1/Tc1 cells probably need to be enhanced by vaccination with the appropriate cancer antigenic peptides or by injection of the autologus tumor peptide-specific T cells expanded in vitro.

The role of diet and other environmental factors in the causation of gastric cancer in Iran--a population based study

Despite a declining trend in the incidence of gastric cancer (GC), it is still a major global public health concern of the 21st century. The rates of GC reported from Ardabil Province, Iran, are among the highest in the world. To investigate risk factors for GC in Ardabil, we undertook a population-based case-control study. The study aimed to recruit all Ardabil residents newly diagnosed with GC in the time period of 2004-2005, and 2 controls per case. Participants were interviewed using a structured questionnaire. Ten milliliters of blood was collected for blood grouping and investigating the presence of IgG antibodies against Helicobacter pylori. During the study period, 217 people with GC and 394 controls were recruited. In multivariate analysis, diet and Helicobacter pylori infection (OR = 2.41; 95% CI: 1.35-4.32) were found to be the factors that were most strongly related to GC. High intake of Allium vegetables (OR = 0.35) and fruit, especially citrus fruit (OR = 0.31) and consumption of fresh fish (OR = 0.37) were significantly protective. On the other hand, consumption of red meat (OR = 3.40) and dairy products (OR = 2.28) were positively associated with the risk of GC. People who had a preference for higher salt intake (OR = 3.10) and drinking strong and hot tea (OR = 2.64 and 2.85, respectively) were at higher risk. In conclusion, Helicobacter pylori infection as measured by serum IgG as well as the consumption of red meat and dairy products increases the risk of GC in Ardabil, while the intake of fresh fruit and fresh fish decrease the risk.

Effect of Helicobacter pylori eradication on incidence of gastric cancer in human and animal models: underlying biochemical and molecular events

BACKGROUND

Gastric cancer remains one of the most common cancers worldwide. A strong association exists between Helicobacter pylori infection and the risk of developing noncardia gastric cancer. H. pylori eradication by antibiotic treatment is regarded as a primary chemoprevention strategy to reduce gastric cancer incidence.

AIM

To analyze the efficacy of H. pylori eradication in preventing gastric cancer in human and animal models, and to discuss whether biochemical, genetic, and epigenetic changes associated with H. pylori infection are reversible after curing the infection.

RESULTS

Several intervention trials have indicated that in some patients, H. pylori eradication leads to regression and prevents the progression of precancerous lesions. The eradication therapy reduces gastric cancer incidence in patients without any precancerous lesions at the baseline and is most effective before the development of atrophic gastritis. A few recent intervention studies in Japan have demonstrated significant prophylactic effects of eradication therapy on the development of gastric cancer, suggesting the use of eradication therapy in high-risk populations as a gastric cancer reduction strategy. However, gastric cancer may still develop despite successful eradication therapy. Studies in animal models have confirmed the use of eradication therapy at an early point of infection to prevent gastric cancer development.

CONCLUSION

H. pylori eradication may not completely abolish the risk of gastric cancer. However, eradication therapy may be used in high-risk populations to reduce gastric cancer incidence. It can reverse many biochemical, genetic, and epigenetic changes that H. pylori infection induces in the stomach.

Association of Helicobacter pylori infection and diet on the risk of gastric cancer: a case-control study in Hawaii

OBJECTIVE

The risk factors most strongly associated with gastric cancer are the gastric bacteria Helicobacter pylori and diet. Utilizing data from a case-control study among residents in Hawaii, we examined the association of diet, presence of H. pylori, and non-cardia gastric cancer risk.

METHODS

Serum taken at diagnosis for cases (n = 212) and at interview for controls (n = 336) was assayed for IgG antibodies to H. pylori group antigens and to a recombinant fragment of the cytotoxin-associated antigen A (CagA) protein, and subjects completed food frequency questionnaires. Risk measures were calculated using logistic regression. The likelihood ratio test was used to assess interactions.

RESULTS

Inverse associations were found between gastric cancer risk and increasing intake of several micronutrients and vegetables among all individuals. For H. pylori/CagA-positive subjects, significant trends were present for total, green, and yellow vegetables, while a significant trend was present only for yellow vegetables among H. pylori/CagA-negative individuals. For intestinal gastric cancer, there was a suggestion that intake of vegetables, especially cruciferous vegetables, had a stronger protective effect for the H. pylori/CagA-positive group.

CONCLUSIONS

Diet may play a greater role in the etiology of non-cardia gastric cancer among individuals with evidence of H. pylori infection than among those without.

Helicobacter pylori infection: a clinical overview

BACKGROUND

Helicobcater pylori colonizes the stomach of more than half of the world's population, and the infection continues to play a key role in the pathogenesis of a number of gastroduodenal diseases. Colonization of the gastric mucosa with Helicobcater pylori results in the development of chronic gastritis in all infected individuals and in a subset of patients chronic gastritis progresses to complications (i.e. ulcer disease, gastric neoplasias, some distinct extragastric disorders). The clinical outcome of the disease is dependent on many variables, including Helicobcater pylori genotype, innate host physiology, genetic predisposition and environmental factors. Helicobcater pylori eradication decreases the incidence of gastroduodenal ulcer and prevents its recurrence. Helicobcater pylori eradication for gastric cancer prevention has been suggested by preclinical research and clinical trials, showing even reversibility of precancerous lesions (atrophic gastritis and intestinal metaplasia) after Helicobcater pylori eradication.

AIMS

To review the current literature about H. pylori and its related pathologies.

CONCLUSION

At present, several clinical manifestations are recognized to be causally linked to Helicobcater pylori infection, and most of them can be cured by Helicobcater pylori eradication. Besides the relationship of Helicobcater pylori and gastroduodenal diseases, it has been well established that Helicobcater pylori infection is also involved in some extragastrointestinal diseases.

Cytogenetic and molecular aspects of gastric cancer: clinical implications

Gastric cancer is of major importance world-wide being the second most common cause of cancer-related death in the world. According to Lauren's histological classification gastric cancer is divided in two groups, the better differentiated intestinal carcinomas and the poorly differentiated diffuse-type cancers. The genetic changes underlying the initiation and progression of gastric cancer are not well defined. Gastric carcinogenesis is a multistep process involving a number of genetic and epigenetic factors. Although it has been proposed that different genetic pathways exist for differentiated and undifferentiated carcinomas, the two histological subtypes of gastric cancer share some common genetic alterations. Currently, tumor histology and pathologic stage are the major prognostic variables used in the clinical practice for gastric cancer patients. However, it is known that tumors with similar morphology may differ in biological aggressiveness, prognosis and response to treatment. Molecular genetic analysis of gastric cancer revealed a number of associations of certain genetic changes with pathological features, tumor biological behavior and prognosis of gastric cancer patients, suggesting that these genetic abnormalities might play an important role in gastric tumorigenesis. Increasing evidence suggests that the molecular genetic changes could be helpful in the clinical setting, contributing to prognosis and management of patients. Regarding epigenetic events in gastric tumorigenesis, a number of methylating markers have been proposed for risk assessment, prognostic evaluation and as therapeutic targets. However, further research is required in order to systematically investigate the genetic changes in gastric cancer estimating also their usefulness in the clinical practice. A good understanding of the genetic changes underlying gastric carcinogenesis may provide new perspectives for prognosis and screening of high risk individuals. Some of the genetic alterations could definitely improve tumor classification and management of gastric cancer patients. Also, based on molecular data identified in gastric cancer novel therapeutics might help to improve the treatment of this disease.

Epigenetic alterations due to diet and Helicobacter pylori infection in gastric carcinogenesis

Sporadic gastric cancer is considered to be the result of a progressive accumulation of genotypic changes due to an adverse environment (i.e., diet and Helicobacter pylori infection). The main molecular mechanism implicated in cancer-related molecular alterations is of epigenetic nature, which includes DNA methylation and histone modification. Diet may influence the methylation status supplying methyl groups S-adenosyl-methionine formation, modifying DNA methyltransferase activity and influencing DNA demethylation activity. H. pylori may affect DNA methyltransferase directly or through inflammatory mediators (e.g., reactive oxygen species or nitric oxide). In conclusion, gastric cancer is a multistep process due to an adverse environment over a long period of time. Dietary habit and H. pylori infection can induce epigenetic alterations that, in turn, trigger gastric carcinogenesis.