Nutrition and gastric cancer risk: an update

Effects of Diet on Aristolochic Acid-DNA Adduct Formation: Implications for Balkan Endemic Nephropathy Etiology

Prolonged exposure to aristolochic acids (AAs) through AA-containing herbal medicine or AA-contaminated food is associated with the development of aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN), both public health risks to which the World Health Organization is calling for global action to remove exposure sources. The AA exposure-induced DNA damage is believed to be related to both the nephrotoxicity and carcinogenicity of AA observed in patients suffering from BEN. While the chemical toxicology of AA is well-studied, we investigated in this study the understated effect of different nutrients, food additives, or health supplements on DNA adduct formation by aristolochic acid I (AA-I). By culturing human embryonic kidney cells in an AAI-containing medium enriched with different nutrients, results showed that cells cultured in fatty acid-, acetic acid-, and amino acid-enriched media produced ALI-dA adducts at significantly higher frequencies than that cultured in the normal medium. ALI-dA adduct formation was most sensitive to amino acids, indicating that amino acid- or protein-rich diets might lead to a higher risk of mutation and even cancer. On the other hand, cells cultured in media supplemented with sodium bicarbonate, GSH, and NAC reduced ALI-dA adduct formation rates, which sheds light on their potential use as risk-mitigating strategies for people at risk of AA exposure. It is anticipated that the results of this study will help to better understand the effect of dietary habits on cancer and BEN development.

Cruciferous vegetables as a treasure of functional foods bioactive compounds: Targeting p53 family in gastrointestinal tract and associated cancers

In the past few years, phytochemicals from natural products have gotten the boundless praise in treating cancer. The promising role of cruciferous vegetables and active components contained in these vegetables, such as isothiocyanates, indole-3-carbinol, and isothiocyanates, has been widely researched in experimental in vitro and in vivo carcinogenesis models. The chemopreventive agents produced from the cruciferous vegetables were recurrently proven to affect carcinogenesis throughout the onset and developmental phases of cancer formation. Likewise, findings from clinical investigations and epidemiological research supported this statement. The anticancer activities of these functional foods bioactive compounds are closely related to their ability to upregulate p53 and its related target genes, e.g., p21. As the “guardian of the genome,” the p53 family (p53, p63, and p73) plays a pivotal role in preventing the cancer progression associated with DNA damage. This review discusses the functional foods bioactive compounds derived from several cruciferous vegetables and their use in altering the tumor-suppressive effect of p53 proteins. The association between the mutation of p53 and the incidence of gastrointestinal malignancies (gastric, small intestine, colon, liver, and pancreatic cancers) is also discussed. This review contains crucial information about the use of cruciferous vegetables in the treatment of gastrointestinal tract malignancies.

Microbiota and the Immune System-Actors in the Gastric Cancer Story

Simple Summary

Stomach cancer is one of the most commonly diagnosed cancers in the world. Although the number of new cases is decreasing year by year, the death rate for this type of cancer is still high. The heterogeneous course and the lack of symptoms in the early stages of the disease mean that the diagnosis is made late, which translates into a worse prognosis for such patients. That is why it is so important to analyze potential risk factors that may increase the risk of developing gastric cancer and to search for new effective methods of treatment. These requirements are met by the analysis of the composition of the gastric microbiota and its relationship with the immune system, which is a key element in the human anti-cancer fight. This publication was created to systematize the current knowledge on the impact of dysbiosis of human microbiota on the development and progression of gastric cancer. Particular emphasis was placed on taking into account the role of the immune system in this process.

Abstract

Gastric cancer remains one of the most commonly diagnosed cancers in the world, with a relatively high mortality rate. Due to the heterogeneous course of the disease, its diagnosis and treatment are limited and difficult, and it is associated with a reduced prognosis for patients. That is why it is so important to understand the mechanisms underlying the development and progression of this cancer, with particular emphasis on the role of risk factors. According to the literature data, risk factors include: changes in the composition of the stomach and intestinal microbiota (microbiological dysbiosis and the participation of Helicobacter pylori), improper diet, environmental and genetic factors, and disorders of the body’s immune homeostasis. Therefore, the aim of this review is to systematize the knowledge on the influence of human microbiota dysbiosis on the development and progression of gastric cancer, with particular emphasis on the role of the immune system in this process.

The Effects of Vitamins and Micronutrients on Helicobacter pylori Pathogenicity, Survival, and Eradication: A Crosstalk between Micronutrients and Immune System

Helicobacter pylori as a class I carcinogen is correlated with a variety of severe gastroduodenal diseases; therefore, H. pylori eradication has become a priority to prevent gastric carcinogenesis. However, due to the emergence and spread of multidrug and single drug resistance mechanisms in H. pylori, as well as serious side effects of currently used antibiotic interventions, achieving successful H. pylori eradication has become exceedingly difficult. Recent studies expressed the intention of seeking novel strategies to improve H. pylori management and reduce the risk of H. pylori-associated intestinal and extragastrointestinal disorders. For which, vitamin supplementation has been demonstrated in many studies to have a tight interaction with H. pylori infection, either directly through the regulation of the host inflammatory pathways or indirectly by promoting the host immune response. On the other hand, H. pylori infection is reported to result in micronutrient malabsorption or deficiency. Furthermore, serum levels of particular micronutrients, especially vitamin D, are inversely correlated to the risk of H. pylori infection and eradication failure. Accordingly, vitamin supplementation might increase the efficiency of H. pylori eradication and reduce the risk of drug-related adverse effects. Therefore, this review aims at highlighting the regulatory role of micronutrients in H. pylori-induced host immune response and their potential capacity, as intrinsic antioxidants, for reducing oxidative stress and inflammation. We also discuss the uncovered mechanisms underlying the molecular and serological interactions between micronutrients and H. pylori infection to present a perspective for innovative in vitro investigations, as well as novel clinical implications.

Relationship between maximum occlusal force and gastrointestinal cancer in community-dwelling older Japanese adults

Globally, the cancer burden is expected to increase as populations are ageing. Therefore, cancer prevention among older age groups is important. This prospective cohort study examined the relationship between the number of remaining teeth, maximum occlusal force, and incidence of gastrointestinal cancer in community-dwelling older Japanese individuals using data from the Tsurugaya project; 847 participants were included. The exposure variables were the number of remaining teeth and the maximum occlusal force, with the outcome being the incidence of gastrointestinal cancer. Covariates were age, sex, medical history, smoking, alcohol consumption, educational attainment, and physical function. The Cox proportional hazard model was used to examine the relationship between the number of remaining teeth, maximum occlusal force, and incidence of gastrointestinal cancer. With a median follow-up of 7.6 years, 63 participants were confirmed to have gastrointestinal cancer. The risk of gastrointestinal cancer was significantly higher in those with an occlusal force lower than the median (hazard ratio, 2.80; 95% confidence interval, 1.54–5.10). No significant risk difference was found according to the number of remaining teeth. Low maximum occlusal force was associated with the incidence of gastrointestinal cancer in community-dwelling older Japanese adults.

Community-driven research in the canadian arctic: dietary exposure to methylmercury and gastric health outcomes

Indigenous Arctic Canadians have a higher prevalence of gastric neoplasms relative to North Americans of European ancestry. We investigated the hypothesis that low-dose methylmercury exposure from eating fish/whale increases the risk of gastric cancer in Arctic communities. We used intermediate endpoints from an established model of gastric carcinogenesis: intestinal metaplasia, atrophy, and severe chronic gastritis. During 2008-2012, we obtained gastric biopsies from participants of community-driven projects in 3 communities. In 2016, we collected hair samples to measure methylmercury levels and interviewed them about diet. In cross-sectional analysis, logistic regression estimated odds ratios for the estimated effect of hair-methylmercury concentration on the prevalence of each pathology outcome stratified by selenium intake. Among 80 participants, prevalence of intestinal metaplasia, atrophy and severe chronic gastritis was 17, 29 and 38%, respectively. Adjusted Odds of severe chronic gastritis and atrophy were highest at hair-methylmercury concentrations ≥1μg/g when estimated selenium intake was 0, and approached 0 for all methylmercury levels as estimated selenium intake increased. Gastric pathology increased with methylmercury exposure when selenium intake was low. Though limited by small numbers, these findings suggest selenium ingested by eating fish/whale may counter harmful effects of methylmercury exposure in Arctic populations.

Diagnostic Value of Serum Pepsinogen Levels for Screening Gastric Cancer and Atrophic Gastritis in Asymptomatic Individuals: A Cross-Sectional Study

Background

Pepsinogens (PGs) can be used for gastric cancer (GC) screening, but the cutoff levels vary among studies, and PG levels are influenced by numerous factors. The aim of this article is to examine the diagnostic value of PG levels and Helicobacter pylori (Hp) status for GC and atrophic gastritis screening in asymptomatic individuals undergoing health checkup in China.

Patients and Methods

This was a multicenter cross-sectional study of subjects who underwent health checkup from 10/2016 to 10/2018 at nine International Healthcare Centers in China. All participants underwent gastroscopy and pathological examination, serum PG, ¹³C-urea breath test, and/or Hp serological current infection marker rapid test, all on the same day. PG-related parameters were analyzed in different Hp subgroups and regions.

Results

The patients were grouped as non-atrophic (NAG, n = 1,590), mild to moderate atrophic (MAG, n = 273), severe atrophic (SAG, n = 49), and GC (n = 10). The serum PG levels in these groups decreased with increasing pathological severity. In the same pathological groups, PGI and PGII levels were higher in the Hp-positive subgroup, while PGR (PGI/PGII ratio) was lower (P < 0.05). The best cutoff values for atrophy diagnosis were PGI ≤73.1 ng/ml and PGR ≤9.8, for severe atrophy were PGI ≤63.9 ng/ml and PGR ≤9.09, and for GC was PGR ≤4.7 (all P < 0.05 and area under the curve >0.7). The cutoff points varied with Hp status and China regions.

Conclusion

Serum PG levels might be used for the screening of gastric atrophic gastritis lesions. The results suggest that different cutoff values should possibly be used in different Hp status groups and geographical regions, but it will have to be validated in future studies. Future studies should also examine the value of PG levels for GC detection.

Gastric cancer: epidemiology, biology, and prevention: a mini review

Gastric cancer is one of the most common causes of cancer-related mortality worldwide. The objective of this article is to review the epidemiology and biology of gastric cancer risk. This literature review explores the biological, clinical, and environmental factors that influence the rates of this disease and discuss the different intervention methods that may not only increase the awareness of gastric cancer but also increase screening in efforts to reduce the risk of gastric cancer. Helicobacter pylori infection is the primary risk factor for gastric cancer. Additional risk factors include geographical location, age, sex, smoking, socioeconomic status, dietary intake, and genetics. Primary and secondary prevention strategies such as dietary modifications and screenings are important measures for reducing the risk of gastric cancer. Interventions, such as H. pylori eradication through chemoprevention trials, have shown some potential as a preventative strategy. Although knowledge about gastric cancer risk has greatly increased, future research is warranted on the differentiation of gastric cancer epidemiology by subsite and exploring the interactions between H. pylori infection, genetics, and environmental factors. Better understanding of these relationships can help researchers determine the most effective intervention strategies for reducing the risk of this disease.

Dietary patterns and gastric cancer risk in a Korean population: a case-control study

PURPOSE

Dietary pattern analysis has been considered as an approach to capture the complex interactions of overall diet, which are often lost in studies of single dietary components (e.g., foods and nutrients). The aim of this study was to identify the major dietary patterns of Koreans via principal component analysis based on the food groups and to investigate the association between dietary patterns and gastric cancer (GC) risk.

METHODS

In this study, participants were recruited from the National Cancer Center, Korea. Among them, 415 cases were diagnosed with early GC, and 830 controls were age- and sex-matched at a ratio of 1:2. To determine the subjects' dietary patterns, 34 predefined food groups based on the 106-item semiquantitative food frequency questionnaire (SQFFQ) were used. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated across the tertiles of dietary pattern scores using logistic regression models.

RESULTS

The two dietary patterns derived in this study were named westernized and prudent. Those patterns explained 24.83% of the total variation in food intake. Higher scores on the prudent pattern was inversely associated with the risk of GC (OR [95% CI] for the highest vs. lowest tertiles: 0.58 [0.41-0.84], p for trend = 0.004).

CONCLUSION

Our findings suggest that adherence to the prudent dietary pattern represented by high loadings of vegetables and fruits, was associated with lower GC risk. Further studies with a prospective design and larger sample sizes are necessary.

Genomic Characterization of Non-Invasive Differentiated-Type Gastric Cancer in the Japanese Population

Background and aims: Recent genomic characterization of gastric cancer (GC) by sequencing has revealed a large number of cancer-related genes. Research to characterize the genomic landscape of cancer has focused on established invasive cancer to develop biomarkers for therapeutic or diagnostic targets, and nearly all GC reports have been about advanced GC. The aim of this study is to identify recurrently mutated genes in non-invasive GC and, in particular, the driver mutations that are associated with the development of GC. Methods and results: We performed whole-exome sequencing of 19 fresh frozen specimens of differentiated-type non-invasive GC and targeted sequencing for 168 genes of 30 formalin-fixed paraffin-embedded archival specimens of differentiated-type non-invasive GC. We found that TP53 and LRP1 are significantly associated with non-invasive GC. It has been reported that LPR1 is associated with CagA autophagy in gastric mucosa. Therefore, we downloaded RNA sequence data for gastric cancer from the The Cancer Genome Atlas (TCGA) Genomic Data Commons Data Portal and examined the differences in LRP1 gene expression levels. The expression level was significantly lower in cases without LRP1 mutation than in cases with LRP1 mutation. Based on these results, fluorescent immunostaining for CagA was performed for 49 of the above samples to evaluate CagA accumulation within the cancerous tissue. Accumulation of CagA was significantly greater when an LRP1 mutation was present than without a mutation. Conclusion: These data suggest that LRP1 mutation is an important change promoting the transformation of gastric mucosa to GC early in the carcinogenesis of cancer.

miR-30a-3p Targets MAD2L1 and Regulates Proliferation of Gastric Cancer Cells

Purpose

This study was done to investigate the inhibition effects of miR-30a-3p on mitotic arrest deficient 2 like 1 (MAD2L1) expression and the proliferation of gastric cancer cells.

Patients and methods

Cluster analysis and the TCGA database were used to screen the key genes highly expressed in gastric cancer. Based on the LinkedOmics website, the correlation between the miR-30a-3p and the cell cycle-related target gene MAD2L1 in gastric cancer was analyzed. The mRNA and protein expression levels were detected with the quantitative real-time PCR and Western blot analysis. The cell proliferation and cell cycle were also detected and analyzed.

Results

Bioinformatics analysis showed that MAD2L1 was highly expressed in tumor tissues compared with normal tissues. Compared with normal tissues, the miR-30a-3p was significantly decreased in the gastric cancer tissues. Moreover, MAD2L1 was significantly negatively correlated with the miR-30a-3p expression. Furthermore, over-expression of miR-30a-3p decreased the expression of MAD2L1 at the protein level, which inhibited the proliferation of AGS and BGC-823 gastric cancer cells. In addition, the cell cycles of AGS and BGC-823 cells were arrested at the G0/G1 phase.

Conclusion

MAD2L1 is a pro-oncogene which is up-regulated in gastric cancer. The miR-30a-3p can down-regulate the MAD2L1 expression, inhibiting the proliferation of gastric cancer cells and affect the cell cycle.

The Protective Effect of Curcumin against Nitrosamine-Induced Gastric Oxidative Stress in Rats

Curcumin has a wide spectrum of biological, pharmaceutical, and antioxidant effects in cancer experimental models. Nitrosamine is commonly used as an experimental oxidizing agent which induces gastric oxidative stress and gastric carcinogenesis in rats. We examined the antioxidant potential effect of curcumin against nitrosamine-induced gastric oxidative stress in rats. Forty Sprague-Dawley rats were randomly divided into 4 groups (10 rats/group). The control group was fed a standard diet and received a single dose of normal saline, the nitrosamine-treated group was fed a standard diet and received an intraperitoneal injection of nitrosamine at a single dose of 100 mg/kg body weight (b.w.). The other two groups received a daily dose of curcumin (200 mg/kg b.w.) via intra-gastric intubation in the presence or absence of nitrosamine injection. After 16 weeks, all rats were sacrificed, and the gastric tissues were dissected for histopathological examination and for biochemical measurements of oxidative stress indices. Our results showed that nitrosamine causes oxidative stress in gastric tissues as evidenced by glutathione depletion, increased level of lipid peroxides, nitric oxide release, impairment of total antioxidant capacity, DNA oxidative damage, and inhibition of antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase, and superoxide dismutase). Histopathological findings revealed abnormal gastric architecture in association with nitrosamine injection compared to the non-treated control group. Curcumin significantly suppressed the gastric oxidative damage associated with nitrosamine treatment and mitigated its histopathological effect. These results suggest that curcumin, as an antioxidant, has a therapeutic effect against oxidative stress-mediated gastric diseases.

Association of RAGE gene four single nucleotide polymorphisms with the risk, invasion, metastasis and overall survival of gastric cancer in Chinese

Objectives: The receptor for advanced glycation end products (RAGE) is an oncogenic trans-membranous receptor expressed in many cells. The aim of this study was to clarify the association between RAGE gene 4 single nucleotide polymorphisms (SNPs) and the risk, invasion, metastasis and overall survival of gastric cancer.

Methods and Results: We performed a hospital-based case-control study involving 369 gastric cancer patients and 493 cancer free controls. Four widely-studied SNPs, rs1800625 (T-429C), rs1800624 (T-374A), rs2070600 (Gly82Ser) and rs184003 (G1704T) in RAGE gene, were genotyped by the polymerase chain reaction - ligase detection reaction method. The RAGE gene rs1800625 TT genotype and T allele were significantly associated with a reduced risk of gastric cancer (TT vs. CC: adjusted odds ratio [OR]: 0.72, 95% CI: 0.55-0.95, p=0.021; T vs. C: adjusted OR: 0.67, 95% CI: 0.46-0.97, p=0.032). No hints of significance were detected for the other three SNPs in association with gastric cancer risk. Moreover, rs1800625 and rs184003 were significantly associated with tumor clinical stage (p=0.010 and 0.032, respectively). Survival curves differed significantly between the genotypes of rs1800625.

Conclusions:RAGE gene SNP rs1800625 was significantly associated with gastric cancer risk, and rs1800625 and rs184003 were related to tumor clinical stage, indicating that RAGE gene may be a gastric cancer-susceptibility gene.

From humans to hydra: patterns of cancer across the tree of life

Cancer is a disease of multicellularity; it originates when cells become dysregulated due to mutations and grow out of control, invading other tissues and provoking discomfort, disability, and eventually death. Human life expectancy has greatly increased in the last two centuries, and consequently so has the incidence of cancer. However, how cancer patterns in humans compare to those of other species remains largely unknown. In this review, we search for clues about cancer and its evolutionary underpinnings across the tree of life. We discuss data from a wide range of species, drawing comparisons with humans when adequate, and interpret our findings from an evolutionary perspective. We conclude that certain cancers are uniquely common in humans, such as lung, prostate, and testicular cancer; while others are common across many species. Lymphomas appear in almost every animal analysed, including in young animals, which may be related to pathogens imposing selection on the immune system. Cancers unique to humans may be due to our modern environment or may be evolutionary accidents: random events in the evolution of our species. Finally, we find that cancer‐resistant animals such as whales and mole‐rats have evolved cellular mechanisms that help them avoid neoplasia, and we argue that there are multiple natural routes to cancer resistance.

Gastric cancer & prospects of cancer in Saudi Arabia peninsula

Gastric cancer is classified to be an aggressive disease with poor treatment outcome, as most cases remain undetected until later stages, wherein surgery and few chemotherapeutics become the only recommended treatment course. The process of cancer development is multistep involving many stages and types of precancerous lesions, and hence, routine monitoring becomes a necessity in those detected with these or exposed to risk factors. Studying the pattern of gastric cancer for any geographical region is also important to control mortality and focus on implementation of efficient management and treatment guidelines. The cause for gastric cancer can be genetic, racial as well as environmental, and hence the pattern of this malignancy differs across geographical regions and between the developing and the developed nations. In case of the Kindgom of Saudi Arabia, very few hospital-based reports have been published highlighting the pattern of gastric cancer, and the associated incidence and mortality rates. However, classified to be one of the most crucial cancer forms in Saudi Arabia, research pertaining to epidemiology, presentation and pathological features are limited. Studying gastric cancer occurrence from public health viewpoint is important also because eradication of causative agents like those that H. pylori has also shown been not reduce the risk of cancer development among individuals with atrophic metaplastic gastritis. In case of Saudi Arabia, many inherent risks for this malignancy exists like waterpipe smoking and shift in diet pattern from the traditional Mediterranean diet. Our review focusses on pattern of gastric cancer on a global scale in comparison to scenario in Saudi Arabia. The aim is to encompass all of the less stressed upon facts about this malignancy in the Kingdom, paving way for future work in this regards.

Human health risk assessment on the consumption of fruits and vegetables containing residual pesticides: A cancer and non-cancer risk/benefit perspective

Pesticide residues in food is a public health concern. This study aimed to evaluate health risk and benefit associated with chronic consumption of fruits and vegetables (F&V) containing residual pesticides in the province of Quebec, Canada. Based on a representative sample of Quebecers (n=4727, aged 1-79) enrolled in the Canadian nutrition survey, population's mean chronic dietary exposure through consumption of F&V was evaluated for 169 different pesticide active ingredients (PAI), including 135 for which toxicological reference values (TRV) were available in the literature. Total lifetime cancer risk was estimated to be 3.3×10^-4 considering the 28 substances for which an oral slope factor was also available. Non-cancer risk quotients greater than 1 were obtained at the 95th percentile of children's exposure for 10 of the 135 PAIs, and considering the most severe pesticide-specific TRV. Dithiocarbamates and imazalil are the authorized PAI that contribute the most to cancer and non cancer risk; they are therefore identified as "priority" PAI. For each estimated case of cancer triggered by PAI exposure, at least 88 cases were deemed prevented by the consumed F&V, based on the population's etiological fraction of the cancer risk that F&V prevent. Concluding, chronic health risks investigated are low and health benefits of F&V consumption by far outweigh the PAI-related risk. However, risk estimates are not negligeable and uncertainties remain. Thus, reducing PAI exposure through F&V consumption with a particular focus on "priority" PAI mentionned above, while maintaining an abundant and varied F&V diet, is desirable.

Re-evaluation of sodium nitrate (E 251) and potassium nitrate (E 252) as food additives

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provided a scientific opinion re-evaluating the safety of sodium nitrate (E 251) and potassium nitrate (E 252) when used as food additives. The current acceptable daily intakes (ADIs) for nitrate of 3.7 mg/kg body weight (bw) per day were established by the SCF (1997) and JECFA (2002). The available data did not indicate genotoxic potential for sodium and potassium nitrate. The carcinogenicity studies in mice and rats were negative. The Panel considered the derivation of an ADI for nitrate based on the formation of methaemoglobin, following the conversion of nitrate, excreted in the saliva, to nitrite. However, there were large variations in the data on the nitrate-to-nitrite conversion in the saliva in humans. Therefore, the Panel considered that it was not possible to derive a single value of the ADI from the available data. The Panel noticed that even using the highest nitrate-to-nitrite conversion factor the methaemoglobin levels produced due to nitrite obtained from this conversion would not be clinically significant and would result to a theoretically estimated endogenous N-nitroso compounds (ENOC) production at levels which would be of low concern. Hence, and despite the uncertainty associated with the ADI established by the SCF, the Panel concluded that currently there was insufficient evidence to withdraw this ADI. The exposure to nitrate solely from its use as a food additive was estimated to be less than 5% of the overall exposure to nitrate in food based on a refined estimated exposure scenario. This exposure did not exceed the current ADI (SCF, 1997). However, if all sources of exposure to dietary nitrate are considered (food additive, natural presence and contamination), the ADI would be exceeded for all age groups at the mean and the highest exposure.

Gastrin and Gastric Cancer

Gastric cancer is the third leading cause of cancer-related mortality worldwide. Despite progress in understanding its development, challenges with treatment remain. Gastrin, a peptide hormone, is trophic for normal gastrointestinal epithelium. Gastrin also has been shown to play an important role in the stimulation of growth of several gastrointestinal cancers including gastric cancer. We sought to review the role of gastrin and its pathway in gastric cancer and its potential as a therapeutic target in the management of gastric cancer. In the normal adult stomach, gastrin is synthesized in the G cells of the antrum; however, gastrin expression also is found in many gastric adenocarcinomas of the stomach corpus. Gastrin's actions are mediated through the G-protein-coupled receptor cholecystokinin-B (CCK-B) on parietal and enterochromaffin cells of the gastric body. Gastrin blood levels are increased in subjects with type A atrophic gastritis and in those taking high doses of daily proton pump inhibitors for acid reflux disease. In experimental models, proton pump inhibitor-induced hypergastrinemia and infection with Helicobacter pylori increase the risk of gastric cancer. Understanding the gastrin:CCK-B signaling pathway has led to therapeutic strategies to treat gastric cancer by either targeting the CCK-B receptor with small-molecule antagonists or targeting the peptide with immune-based therapies. In this review, we discuss the role of gastrin in gastric adenocarcinoma, and strategies to block its effects to treat those with unresectable gastric cancer.

Association between Dietary Inflammatory Index and Gastric Cancer Risk in an Italian Case-Control Study

BACKGROUND

In this study, we explored the association between the dietary inflammatory index (DII) and gastric cancer risk in an Italian case-control study.

MATERIALS AND METHODS

Cases were 230 patients with incident, histologically confirmed cases of gastric cancer from the Greater Milan area, Northern Italy. Controls were 547 frequency-matched subjects admitted to the same network of hospitals as cases for a wide spectrum of acute, non-neoplastic conditions. The DII was computed using a reproducible and valid 78-item food frequency questionnaire. Odds ratios (ORs) were estimated through logistic regression models conditioned on age and sex and adjusted for recognized confounding factors, including total energy intake.

RESULTS

Subjects with the most pro-inflammatory diet had a higher risk of gastric cancer compared to subjects with the most anti-inflammatory diet (ORQuartile4vs1 = 2.35, 95% confidence interval, 1.32, 4.20; P-trend = 0.004).

CONCLUSION

These results indicate that a pro-inflammatory diet, as indicated by higher DII score, was associated with increased risk of gastric cancer.

Meeting the Vitamin A Requirement: The Efficacy and Importance of β-Carotene in Animal Species

Vitamin A is essential for life in all vertebrate animals. Vitamin A requirement can be met from dietary preformed vitamin A or provitamin A carotenoids, the most important of which is β-carotene. The metabolism of β-carotene, including its intestinal absorption, accumulation in tissues, and conversion to vitamin A, varies widely across animal species and determines the role that β-carotene plays in meeting vitamin A requirement. This review begins with a brief discussion of vitamin A, with an emphasis on species differences in metabolism. A more detailed discussion of β-carotene follows, with a focus on factors impacting bioavailability and its conversion to vitamin A. Finally, the literature on how animals utilize β-carotene is reviewed individually for several species and classes of animals. We conclude that β-carotene conversion to vitamin A is variable and dependent on a number of factors, which are important to consider in the formulation and assessment of diets. Omnivores and herbivores are more efficient at converting β-carotene to vitamin A than carnivores. Absorption and accumulation of β-carotene in tissues vary with species and are poorly understood. More comparative and mechanistic studies are required in this area to improve the understanding of β-carotene metabolism.

The Growth of SGC-7901 Tumor Xenografts Was Suppressed by Chinese Bayberry Anthocyanin Extract through Upregulating KLF6 Gene Expression

To investigate the antitumor effect of anthocyanins extracted from Chinese bayberry fruit (Myrica rubra Sieb. et Zucc.), a nude mouse tumor xenograft model was established. Treatments with C3G (cyanidin-3-glucoside, an anthocyanin) significantly suppressed the growth of SGC-7901 tumor xenografts in a dose-dependent manner. Immunohistochemical staining showed a significant increase in p21 expression, indicating that the cell cycle of tumor xenografts was inhibited. qPCR screening showed that C3G treatment up-regulated the expression of the KLF6 gene, which is an important tumor suppressor gene inactivated in many human cancers. Western blot showed that C3G treatments markedly increased KLF6 and p21 protein levels, inhibited CDK4 and Cyclin D1 expression, but did not notably change the expression of p53. These results indicated that KLF6 up-regulates p21 in a p53-independent manner and significantly reduces tumor proliferation. This study provides important information for the possible mechanism of C3G-induced antitumor activity against gastric adenocarcinoma in vivo.

Adhesive Properties and Acid-Forming Activity of Lactobacilli and Streptococci Under Inhibitory Substances, Such as Nitrates

One of the main requirements for probiotics is their ability to survive during passage through gastrointestinal tract and to maintain their activity at different adverse conditions. The aim of the study was to look for the strains of lactobacilli and streptococci with high adhesive properties even affected by inhibitory substances, such as nitrates (NO3 (-)). To study the adhesion properties hemagglutination reaction of bacterial cells with red blood cells of different animals and humans was used. The acid formation ability of bacteria was determined by the method of titration after 7 days of incubation in the sterile milk. These properties were investigated at different concentrations of NO3 (-). The high concentration (mostly ≥2.0 %) NO3 (-) inhibited the growth of both lactobacilli and streptococci, but compared with streptococcal cultures lactobacilli, especially Lactobacillus acidophilus Ep 317/402, have shown more stability and higher adhesive properties. In addition, the concentrations of NO3 (-) of 0.5-2.0 % decreased the acid-forming activity of the strains, but even under these conditions they coagulated milk and, in comparison to control, formed low acidity in milk. Thus, the L. acidophilus Ep 317/402 with high adhesive properties has demonstrated a higher activity of NO3 (-) transformation.

Helicobacter pylori in gastric carcinogenesis

Gastric cancer still is a major concern as the third most common cancer worldwide, despite declining rates of incidence in many Western countries. Helicobacter pylori (H. pylori) is the major cause of gastric carcinogenesis, and its infection insults gastric mucosa leading to the occurrence of atrophic gastritis which progress to intestinal metaplasia, dysplasia, early gastric cancer, and advanced gastric cancer consequently. This review focuses on multiple factors including microbial virulence factors, host genetic factors, and environmental factors, which can heighten the chance of occurrence of gastric adenocarcinoma due to H. pylori infection. Bacterial virulence factors are key components in controlling the immune response associated with the induction of carcinogenesis, and cagA and vacA are the most well-known pathogenic factors. Host genetic polymorphisms contribute to regulating the inflammatory response to H. pylori and will become increasingly important with advancing techniques. Environmental factors such as high salt and smoking may also play a role in gastric carcinogenesis. It is important to understand the virulence factors, host genetic factors, and environmental factors interacting in the multistep process of gastric carcinogenesis. To conclude, prevention via H. pylori eradication and controlling environmental factors such as diet, smoking, and alcohol is an important strategy to avoid H. pylori-associated gastric carcinogenesis.

Emphasizing the losses or the gains: Comparing situational and individual moderators of framed messages to promote fruit and vegetable intake

Health messages are a commonly used way to promote changes in dietary habits but their efficacy could be enhanced by strategies such as the way in which the presented arguments are framed. This study aimed to test the effectiveness of framed messages (gain vs. loss) on behavioural intention and fruit and vegetable (FV) intake, comparing predictions based on prominent theoretical perspectives on message framing (function of the health behaviour and recipients' motivational orientation) and by further exploring the role of baseline intentions as a potential moderator of the framing effects. Undergraduate students (N = 180) completed the three assessment points in time. At baseline, individual moderators (motivational orientation and intentions) and fruit and vegetable intake were assessed. One week later, participants were randomly assigned to the loss or gain-framed message and indicated their intentions for FV intake the following week. A week later, FV intake over the previous week was assessed. The gain-frame was not conducive, per se, to higher intentions or behaviour. Having intention as the outcome, only baseline intentions moderated the effects of message frame. When considering FV intake as the outcome, both motivational orientation and baseline intentions moderated the effects of message frame, with the loss-frame promoting higher FV intake among individuals who were prevention-oriented and had higher baseline intentions. Findings suggest that the success of framed messages for FV intake depends upon the recipient's characteristics, such as motivational orientation, baseline intentions, and cultural background, with implications for health communication interventions.

Is there any relationship between food habits in the last two decades and gastric cancer in North-Western Iran?

PURPOSE

The aims of this case-control study were to assess the correlation between some food habits in the last two decades and gastric cancer in East Azerbaijan of Iran.

MATERIALS AND METHODS

In this hospital based case control study, 616 patients (212 gastric cancer patients, 404 cancer free patients) were recruited. Food habits of patients over the past two decades were assessed with a structured questionnaire. We used conditional logistic regression analysis for estimating crude and adjusted odds ratios (OR) and their respective 95% confidence intervals (95%CI).

RESULTS

In this study, over-eating, consumption of high fat milk and yogurt and especial types of cheese increased the risk of gastric cancer (All<0.05). Consumption of such especial cheeses such as Koze and Khiki increased the risk of gastric cancer by 12.6 fold (95% CI:1.99-79.36) and 7.36 fold (95% CI:1.33- 40.54), respectively. In addition, high fat food, moldy food, and pickled vegetables consumption as well as reuse of cooking oil for frying were significantly associated with gastric cancer risk. Furthermore, intake of Ghorme (deep fried meat) was positively correlated with gastric cancer risk (OR:1.31;95%CI: 0.91-1.87).

CONCLUSIONS

It can be confirmed that particular food habits which have been very common in East-Azerbaijan in the last two past decades increase risk of gastric cancer. According to our results and taking into account the long latency period of gastric cancer it can be concluded that nutrition education for a healthy diet should be performed from early childhood. However, further well designed cohort studies are needed to achieve more clear results.

Detection of oral Helicobacter Pylori infection using saliva test cassette

OBJECTIVE

To investigate the incidence of oral infection with Helicobacter pylori (H. pylori) and identify related epidemiological factors among freshmen of four colleges in Yancheng.

METHODS

The data, scored positive or negative, were collected on 160 individuals who had been diagnosed by H. pylori Saliva Test Cassette (HPS) during October 2013 to October 2014. H. pylori Saliva Test Cassette (HPS) is to use colloidal gold technique to specifically identify urease in saliva. A standard questionnaire, with variables including sex, educational degree of parents etc., was used in the subjects. Statistical data of diagnostic test were analyzed by SPSS17.0 software.

RESULTS

Out of 160, 82 subjects were detected positive and 78 were negative. In univariate analysis, dental plaque, family history of stomach diseases, habit of washing hands before meals and habit of brushing teeth twice daily were associated negatively with H. pylori infection. Multivariate logistic regression analysis showed that dental plaque and family history of stomach diseases were the risk factors which may be associated with H. pylori infection.

CONCLUSIONS

Dental plaque and family history of gastric diseases were risk factors of oral H. pylori infection. It is vital for the prevention of H. pylori infection to focus on health education and oral hygiene, and avoid transmission by oral-oral route as well.

Anticancer Effect of Lycopene in Gastric Carcinogenesis

Gastric cancer ranks as the most common cancer and the second leading cause of cancer-related death in the world. Risk factors of gastric carcinogenesis include oxidative stress, DNA damage, Helicobacter pylori infection, bad eating habits, and smoking. Since oxidative stress is related to DNA damage, smoking, and H. pylori infection, scavenging of reactive oxygen species may be beneficial for prevention of gastric carcinogenesis. Lycopene, one of the naturally occurring carotenoids, has unique structural and chemical features that contributes to a potent antioxidant activity. It shows a potential anticancer activity and reduces gastric cancer incidence. This review will summarize anticancer effect and mechanism of lycopene on gastric carcinogenesis based on the recent experimental and clinical studies.

Dietary intake of Zinc, serum levels of Zinc and risk of gastric cancer: A review of studies

Gastric cancer (GC) is considered as most fourth common cancer in the world. Findings from animal, experimental and epidemiologic studies indicate that diet plays an important role in the etiology of stomach cancer. Among dietary factors, Zinc status has received great attention in recent years. The purpose of the present study was to review the association of serum levels of Zinc, dietary intake of Zinc and GC risk. A complete search was performed about the association of Zinc status and risk of GC was in databases electronic through such as ISI web of science, PubMed, Scopus, IrMedx and SID. Our results of current review suggest that dietary intake of Zinc and serum levels of Zinc are lower in GC patient. In other word, high serum levels of Zinc may be protective in GC risk. However, it seems further studies in particular epidemiological studies with large scale setting are required to reach a definite conclusion.

Macronutrient intake and stomach cancer

PURPOSE

This study examines the association between intake of selected macronutrients and the risk of stomach cancer in a Northern American population.

METHODS

Mailed questionnaires were completed between 1994 and 1997 in eight Canadian provinces by 1,181 incident, histologically confirmed cases of stomach cancer and 5,039 population controls. Information on nutrient intake was obtained using a food frequency questionnaire. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were derived through unconditional logistic regression to adjust for potential confounders, including an estimate of total energy intake.

RESULTS

Intakes of total fat, saturated fat, and cholesterol were significantly associated with the risk of stomach cancer: The ORs for the highest versus the lowest quartile were 1.58 (95% CI 1.13-2.20), 1.86 (95% CI 1.37-2.52), and 1.75 (95% CI 1.36-2.25), respectively. Total fiber was inversely associated with stomach cancer (p = 0.03). The positive associations with intake of total fat and saturated fat were apparently stronger in women, overweight or obese subjects, and ever smokers. Saturated fat was specifically associated with increased risk of gastric cardia cancer, with an OR of 3.31 (95% CI 1.48-7.43).

CONCLUSIONS

A diet high in saturated fat appears to increase the risk of stomach cancer, particularly among obese subjects and for gastric cardia cancer.

Pathogenetic mechanisms in gastric cancer

Gastric cancer (GC) is a major public health issue as the fourth most common cancer and the second leading cause of cancer-related death. Recent advances have improved our understanding of its molecular pathogenesis, as best exemplified by elucidating the fundamental role of several major signaling pathways and related molecular derangements. Central to these mechanisms are the genetic and epigenetic alterations in these signaling pathways, such as gene mutations, copy number variants, aberrant gene methylation and histone modification, nucleosome positioning, and microRNAs. Some of these genetic/epigenetic alterations represent effective diagnostic and prognostic biomarkers and therapeutic targets for GC. This information has now opened unprecedented opportunities for better understanding of the molecular mechanisms of gastric carcinogenesis and the development of novel therapeutic strategies for this cancer. The pathogenetic mechanisms of GC are the focus of this review.

Medical management of gastric cancer: a 2014 update

Gastric cancer represents a serious health problem on a global scale. It is the second leading cause of cancer-related death worldwide. Novel therapeutic targets are desperately needed because the meager improvement in the cure rate of about 10% realized by adjunctive treatments to surgery is unacceptable as > 50% patients with localized gastric cancer succumb to their disease. Either postoperative chemoradiotherapy (United States), pre-and post-operative chemotherapy (Europe), and adjuvant chemotherapy after a D2 resection (Asia) can all be regarded as standards of care in the localized gastric cancer management. In metastatic disease the addition of trastuzumab to chemotherapy is standard of care in Her2 positive disease. In the HER2 negative population, the treatments remain limited. In the first line setting, the standard of care is a combination of fluoropyrimidine and platinum containing chemotherapy, with or without epirubicin or docetaxel. The results of targeted therapy trials have by and large been disappointing, but none of these trials looked at an appropriately enriched population. Finally there is a meager overall survival benefit in treating patients with metastatic disease in the second line setting, with either irinotecan, docetaxel or ramucirumab however none of these drugs have been compared head to head in a well-powered randomized controlled trial.

One-carbon metabolism dietary factors and distal gastric cancer risk in chinese women

BACKGROUND

Previous studies on the association between one-carbon dietary factors and gastric cancer risk have been inconsistent.

METHODS

We investigated this association using data from a prospective study, the Shanghai Women's Health Study (1997-2010), including 323 distal gastric cancer cases identified from 73,009 Chinese women. HRs and 95% confidence intervals (CI) were estimated using Cox proportional hazard regression after adjusting for confounders.

RESULTS

Overall, no statistically significant association of gastric cancer was observed with dietary intake of folate, methionine, or B vitamins. However, when stratified by menopausal status, higher intake of riboflavin was associated with decreased gastric cancer risk in premenopausal women with HR of 0.35 (95% CI, 0.17-0.73), 0.48 (0.24-0.97), 0.28 (0.12-0.65), and 0.23 (0.07-0.91), respectively, for the quintiles 2 to 5 intake groups compared with the lowest quintile intake (P for trend = 0.02). Among premenopausal women, highest intake of folate was associated with increased gastric cancer risk (HR, 2.62; 95% CI, 1.04-6.59). There were no statistically significant associations observed among postmenopausal women.

CONCLUSIONS

These results suggest that dietary factors involved in one-carbon metabolism are associated with gastric cancer risk among premenopausal women.

IMPACT

Riboflavin may be a protective factor and folate may be a risk factor for premenopausal gastric cancer.

Helicobacter pylori and gastric cancer

Infection with Helicobacter pylori is established as the major risk factor for gastric cancer development. Damage of the mucosal barrier due to H. pylori-induced inflammation enhances the carcinogenic effect of other risk factors such as salt intake or tobacco smoking. The genetic disposition of both the bacterial strain and the host can increase the potential towards gastric cancer formation. Genetic variance of the bacterial proteins CagA and VacA is associated with a higher gastric cancer risk, as are polymorphisms and epigenetic changes in host gene coding for interleukins (IL1β, IL8), transcription factors (CDX2, RUNX3) and DNA repair enzymes. Application of high-throughput assays for genome-wide assessment of either genetic structural variance or gene expression patterns may lead to a better understanding of the pathobiological background of these processes, including the underlying signaling pathways. Understanding of the stepwise alterations that take place in the transition from chronic atrophic gastritis, via metaplastic changes, to invasive neoplasia is vital to define the 'point of no return' before which eradication of H. pylori has the potential to prevent gastric cancer. Currently, eradication as preventive strategy is only recommended for high-incidence regions in Asia; large population studies with an adequate follow-up are required to demonstrate the effectiveness of such an approach in Western populations.

Low expression of ERK signaling pathway affecting proliferation, cell cycle arrest and apoptosis of human gastric HGC-27 cells line

This study was carried out for the first time to examine the potential role and the underlying mechanisms of Lycopene in the gastric cancer HGC-27 cells. HGC-27 cells were seeded onto heat-sterilized coverslips in six-well plates and exposed to Lycopene (5, 10, 20, 30 and 40 μmol/L) for periods of 72 h at 37 °C. Results showed that Lycopene (5, 10, 20, 30 and 40 μmol/L) dose-dependently increased NBT positive rate and decreased lactate dehydrogenase activity in HGC-27 cells. In addition, Lycopene (5, 10, 20, 30 and 40 μmol/L) inhibited proliferation and induced G0-G1 phase cell cycle arrest in HGC-27 cells. Western blot and FQRT-PCR analysis showed that Lycopene decreased pERK and extracellular signal-regulated kinase (ERK) protein and mRNA expression in a dose-dependent manner. These findings demonstrate that Lycopene inhibited gastric cancer HGC-27 cells growth and stimulated its apoptosis via the suppressing ERK signaling pathway.

Anti-proliferative and apoptosis-inducing activity of lycopene against three subtypes of human breast cancer cell lines

Although lycopene, a major carotenoid component of tomatoes, has been suggested to attenuate the risk of breast cancer, the underlying preventive mechanism remains to be determined. Moreover, it is not known whether there are any differences in lycopene activity among different subtypes of human breast cancer cells. Using ER/PR positive MCF-7, HER2-positive SK-BR-3 and triple-negative MDA-MB-468 cell lines, we investigated the cellular and molecular mechanism of the anticancer activity of lycopene. Lycopene treatment for 168 consecutive hours exhibited a time-dependent and dose-dependent anti-proliferative activity against these cell lines by arresting the cell cycle at the G₀/G₁ phase at physiologically achievable concentrations found in human plasma. The greatest growth inhibition was observed in MDA-MB-468 where the sub-G₀/G₁ apoptotic population was significantly increased, with demonstrable cleavage of PARP. Lycopene induced strong and sustained activation of the ERK1/2, with concomitant cyclin D1 suppression and p21 upregulation in these three cell lines. In triple negative cells, lycopene inhibited the phosphorylation of Akt and its downstream molecule mTOR, followed by subsequent upregulation of proapoptotic Bax without affecting anti-apoptotic Bcl-xL. Taken together, these data indicate that the predominant anticancer activity of lycopene in MDA-MB-468 cells suggests a potential role of lycopene for the prevention of triple negative breast cancer.

Histopathological changes in rabbit gastric mucosa after chronic exposure to pickled vegetables: an experimental study

Gastric cancer (GC) is very common in Iran. Daily consumption of pickled vegetables is a routine dietary habit in most areas of Iran. Because pickled vegetables have been associated with GC it can be of importance to study the relationship between the two. We have therefore studied the histo-morphological effects of pickled vegetables on the Rabbit gastric mucosa. Forty and twenty healthy male rabbits were respectively allocated in the experimental and control groups. The rabbits were fed freely with pickled (experimental group) and fresh vegetables (control group) for 1 yr. The gastric mucosa of rabbits was examined and the results were compared. In addition to all the rabbits of the control group, 14 rabbits (35%) of the experimental group had normal gastric mucosa. The rest showed abnormal changes including atypia-so called indefinite for dysplasia-in 10 (25%), low-grade dysplasia in 14 (35%), and high-grade dysplasia in 2 (5%). The analysis showed significant difference between results of the 2 groups (P < 0.001). Daily consumption of pickled vegetables can produce atypical and dysplastic changes in the gastric mucosa. Such preneoplastic changes can potentially transform to gastric carcinoma. This process could be prevented by reduction or cessation of daily pickled food consumption.

Quantitative assessment of the influence of glutathione S-transferase T1 null variant on gastric cancer risk

Glutathione S-transferase T1 (GSTT1) catalyzes reactions between glutathione and lipophilic compounds with electrophilic centers, leading to neutralization of toxic compounds, xenobiotics, and products of oxidative stress. In the past decade, a number of case-control studies have been carried out to investigate the relationship between the GSTT1 null polymorphism and gastric cancer (GC), but the results have been inconclusive. To investigate this inconsistency, we performed a meta-analysis of 46 studies involving a total of 9012 GC cases and 14,215 controls for null variant of the GSTT1 gene to evaluate the effect of GSTT1 on genetic susceptibility for GC. Potential sources of heterogeneity including ethnicity, source of control, and sample size were also assessed. Overall, significantly increased GC risk was associated with GSTT1 null polymorphism with OR of 1.20 (95% CI, 1.10-1.32; P < 0.05). In the subgroup analysis by ethnicity, significantly increased risks were found in East Asians and Indians, while no significant associations were found among Caucasian, and Middle Eastern and African populations. By pooling data from 19 studies that considered combinations of GSTT1 and GSTM1 genotypes, a statistically significant increased risk for GC (OR = 2.04, 95% CI, 1.49-2.64; P < 0.05) was detected for individuals with dual deletion in both genes compared with positive genotypes. In addition, we found that cigarette smoking and alcohol drinking may modified the association of GSTT1 null genotypes with the risk of GC. In conclusion, this meta-analysis suggests that GSTT1 null polymorphism is associated with elevated GC risk, but these associations vary in different ethnic populations.

Time characteristics of the effect of alcohol cessation on the risk of stomach cancer--a meta-analysis

BACKGROUND

In the Bagnardi et al. (2001) meta-analysis, it was found that alcohol consumption increases the risk of stomach cancer (OR = 1.32 for heavy drinkers). However, it is unknown if drinking cessation reverses this alcohol-elevated risk.

METHODS

A systematic literature review was performed to provide the information for a meta-analysis where the dose-risk trend was estimated for years since drinking cessation and the risk of stomach cancer. A random effect generalised least squares model for trend estimation was used, employing study characteristics to control for heterogeneity.

RESULTS

Nineteen observational studies were identified in the literature review, of which five studies quantified duration of cessation and risk of stomach cancer, giving a total of 1947 cancer cases. No significant effect of drinking cessation on the risk of stomach cancer could be found (OR = 0.99 CI: 0.97-1.02).

CONCLUSIONS

This result should be interpreted with caution due to the limited number of studies in this area. Recent findings suggest a link between heavy drinking and stomach cancer, especially gastric noncardia, but not for moderate drinking. Since all but one of the included studies in this meta-analysis failed to control for consumption level, the current study could not test if the risk decline following drinking cessation differs between moderate and high consumers.

Pre-existing diabetes mellitus increases the risk of gastric cancer: A meta-analysis

AIM: To systematically assess the association between diabetes and incidence of gastric cancer.

METHODS: We searched MedLine (PubMed), EMBASE, and the Cochrane Library without any limitations with respect to publication date or language, we also searched the references of qualifying articles. Case-control studies and cohort studies comparing the risk of gastric cancer between diabetic patients and control subjects were included. We excluded studies reporting only standardized incidence ratios without control groups and those that investigated only mortality but not incidence. Seventeen studies met our criteria, and the qualities of these studies were assessed using the Newcastle-Ottawa Quality Assessment Scale. We performed a meta-analysis of pre-existing diabetes and gastric cancer incidence using the DerSimonian-Laird method for random-effects. For subgroup analyses, we separated the studies by study type, region, sex and method to determine confounding factors and reliability. We also conducted subgroup analyses to examine the effects of smoking, Helicobacter pylori (H. pylori) infection, and cancer site. Publication bias was evaluated using Begg’s test.

RESULTS: A random-effects model meta-analysis showed an increased gastric cancer risk in diabetic patients [relative risk (RR) = 1.19; 95%CI: 1.08-1.31]. Subgroup analyses indicated that this result persisted in cohort studies (RR = 1.20; 95%CI: 1.08-1.34), in studies on populations of both Western (RR = 1.18; 95%CI: 1.03-1.36) and Eastern countries (RR = 1.19; 95%CI: 1.02-1.38), in a female subgroup (RR=1.24; 95%CI: 1.01-1.52), and in highly qualified studies (RR = 1.17; 95%CI: 1.05-1.31). Moreover, these results persisted when the analysis was confined to studies adjusted for well-known gastric cancer risk factors such as smoking (RR = 1.17; 95%CI: 1.01-1.34) and H. pylori infection (RR = 2.35; 95%CI: 1.24-4.46).

CONCLUSION: Pre-existing diabetes mellitus may increase the risk of gastric cancer by approximately 19%. This effect seems to be unrelated to geographical region.