Synergistic interaction between Helicobacter pylori gastritis and diet in gastric cancer

Gastric microbiota: an emerging player in gastric cancer

Gastric cancer (GC) is a common cancer worldwide with a high mortality rate. Many microbial factors influence GC, of which the most widely accepted one is Helicobacter pylori (H. pylori) infection. H. pylori causes inflammation, immune reactions and activation of multiple signaling pathways, leading to acid deficiency, epithelial atrophy, dysplasia and ultimately GC. It has been proved that complex microbial populations exist in the human stomach. H. pylori can affect the abundance and diversity of other bacteria. The interactions among gastric microbiota are collectively implicated in the onset of GC. Certain intervention strategies may regulate gastric homeostasis and mitigate gastric disorders. Probiotics, dietary fiber, and microbiota transplantation can potentially restore healthy microbiota. In this review, we elucidate the specific role of the gastric microbiota in GC and hope these data can facilitate the development of effective prevention and therapeutic approaches for GC.

Association of Dietary Antioxidant Vitamin Intake and Gastric Cancer Risk According to Smoking Status and Histological Subtypes of Gastric Cancer: A Case-Control Study in Korea

Smoking is a risk factor for gastric cancer (GC) and causes oxidative stress. Antioxidant vitamins may protect against oxidative stress. This study aimed to determine the association between dietary antioxidant vitamin intake and GC risk according to smoking status and the histological subtype. This case-control study included 286 pairs of patients with GC and controls aged 20-79 years enrolled at two hospitals from 2002 to 2006, matched by age (± 2 years), sex, hospital, and participation period (± 1 years). Dietary information was collected using a quantitative food frequency questionnaire (FFQ). When stratified by smoking status, increased intake of vitamin C (OR = 0.38; 95% CI = 0.17-0.84 for highest vs. lowest; P for trend = 0.033) and folate (OR = 0.28; 95% CI = 0.12-0.64 for highest vs. lowest; P for trend = 0.003) decreased GC risk in nonsmokers. Vitamin C (P for interaction = 0.043) and folate (P for interaction =0.015) levels were significantly associated with smoking status. Similar results were observed in nonsmokers with diffuse and mixed types of GC, but not in those with intestinal type of GC. Therefore, we found an inverse association between higher intake of dietary vitamin C and folate with the risk of GC among nonsmokers. These protective associations were strong in nonsmokers with diffuse and mixed types of GC.

Association between soy products, fruits, vegetables, and dairy products and gastric cancer risk in Helicobacter pylori-infected subjects: a case-control study in Korea

BACKGROUND/OBJECTIVES

Consumption of certain protective foods may help inhibit Helicobacter pylori (H. pylori) associated gastric pathologies. However, studies conducted to assess the efficacy of protective foods in H. pylori-infected subjects are either limited or inconsistent. This study evaluated the association of individual or a combination of protective foods on the incidence of gastric cancer (GC) in H. pylori-positive subjects through a case-control study.

MATERIALS/METHODS

Subjects aged 20-79 years were selected from 2 hospitals between December 2002 and September 2006. In total, 134 patients and 212 controls tested positive for H. pylori infection. Among these, we included 82 pairs of cases and controls matched by sex, age (± 5 years), enrollment period (± 1 years), and hospital.

RESULTS

A higher intake of soy products was associated with a significantly lower risk of GC than a lower intake of soy products (odds ratio [OR] = 0.37, 95% confidence interval [CI] = 0.14-0.96). Additionally, a higher fruit intake resulted in a significantly lower risk of GC than a lower fruit intake (OR = 0.35, 95% CI = 0.13-0.94). A combination of food groups was evaluated, and a lower risk of GC was observed with a high intake of both soy products and fruits (OR = 0.20, 95% CI = 0.06-0.67), high intake of soy and dairy products (OR = 0.28, 95% CI = 0.10-0.78) and high intake of fruits and dairy products (OR = 0.28, 95% CI = 0.09-0.83).

CONCLUSIONS

A high intake of soy products or fruits was associated with a lower risk of GC. A combination of soy products or fruits with dairy products was associated with a lower risk of GC. A balanced intake of soy products, fruits, and dairy products may help reduce GC risk.

Mediterranean Dietary Pattern is Associated with Lower Odds of Gastric Cancer: A Case-Control Study

Background

Diet pattern is an important modifiable lifestyle factor. However, epidemiological studies show that the association between dietary patterns and gastric cancer (GC) is conflicting. This study aims to assess the impact of several dietary choices on the risk of GC among newly diagnosed Jordanian patients.

Methods

A case–control study was conducted at major oncology centers and hospitals in Jordan. Study participants included 172 patients with incident gastric cancer and 314 controls. Data was collected using interview-based questionnaires. Dietary intake was estimated using a validated Arabic and reproducible food-frequency questionnaire (FFQ). Dietary patterns were derived using Principal Component Analysis (PCA). Multinomial logistic regression was used to estimate the association between dietary patterns and GC.

Results

Four dietary patterns were itemized; “Mediterranean”, “Prudent”, “Unhealthy” and “High-fruit” dietary patterns. The “Mediterranean” dietary pattern, which includes a diet rich in fresh fruits, vegetables, milk, yogurt, lentils, and olive oil was associated with a significant decrease in the odds ratio (OR) of GC for the third and fourth quartiles (OR, 0.394 (confidence interval (CI): 0.211–0.736); 0.212 (CI: 0.107–0.419), respectively) after adjusting for age, gender, body mass index, smoking, marital status, total energy intake, education level, and physical activity. While the “Unhealthy” and “Prudent” dietary patterns enhance the risk of developing GC, this risk was insignificant at any quartile. Additionally, the “High-Fruit” dietary pattern shows an insignificant protective effect against the risk of GC.

Conclusion

The “Mediterranean” dietary pattern was associated with a reduced risk of GC among Jordanians. However, the other three identified dietary patterns were not significantly associated with the risk of GC.

Risk factors associated with gastric malignancy during chronic Helicobacter pylori Infection

Chronic Helicobacter pylori (Hp) infection is considered to be the single most important risk factor for the development of gastric adenocarcinoma in humans, which is a leading cause of cancer-related death worldwide. Nonetheless, Hp infection does not always progress to malignancy, and, gastric adenocarcinoma can occur in the absence of detectable Hp carriage, highlighting the complex and multifactorial nature of gastric cancer. Here we review known contributors to gastric malignancy, including Hp virulence factors, host genetic variation, and multiple environmental variables. In addition, we assess emerging evidence that resident gastric microflora in humans might impact disease progression in Hp-infected individuals. Molecular approaches for microbe identification have revealed differences in the gastric microbiota composition between cancer and non-cancerous patients, as well as infected and uninfected individuals. Although the reasons underlying differences in microbial community structures are not entirely understood, gastric atrophy and hypochlorhydria that accompany chronic Hp infection may be a critical driver of gastric dysbiosis that promote colonization of microbes that contribute to increased risk of malignancy. Defining the importance and role of the gastric microbiota as a potential risk factor for Hp-associated gastric cancer is a vital and exciting area of current research.

Index-based dietary patterns in relation to gastric cancer risk: a systematic review and meta-analysis

Dietary indices are widely used in diet quality measurement, and the index-based dietary patterns are related to gastric cancer risk. To evaluate the relationship between different kinds of index-based dietary patterns and gastric cancer risk, we systematically searched four English-language databases and four Chinese-language databases. The quality of studies was assessed by the Newcastle–Ottawa Scale. Meta-analyses were performed to estimate the association between gastric cancer incidence and different types of index-based dietary patterns. The OR and hazard ratios (HR) of gastric cancer incidence were calculated by regression models in case–control studies and prospective cohort studies, respectively. The studies were pooled in the random effects model to calculate the summarised risk estimate of the highest quantile interval of dietary indices, taking the lowest as the referent. The dietary indices included different versions of Mediterranean diet score (MDS) and dietary inflammatory index (DII), healthy eating index, Chinese Food Pagoda score and food index score. The meta-analysis was carried out for studies on MDS and DII. The combined OR of gastric cancer for the highest MDS v. the referent was 0·42 (95 % CI 0·2, 0·86), and the combined HR was 0·89 (95 % CI 0·68, 1·17). The combined OR for DII was 2·11 (95 % CI 1·41, 3·15). Higher Mediterranean dietary pattern consumption might reduce gastric cancer risk, while higher inflammatory diet pattern consumption might increase gastric cancer risk.

Arsenic sulfide induces miR-4665-3p to inhibit gastric cancer cell invasion and migration

Purpose

Gastric carcinogenesis is a multistep process and is the second-highest cause of cancer death worldwide with a high incidence of invasion and metastasis. MicroRNAs (miRNAs) engage in complex interactions with the machinery that controls the transcriptome and concurrently target multiple mRNAs. Recent evidence has shown that miRNAs are involved in the cancer progression, including promoting cell-cycle, conferring resistance to apoptosis, and enhancing invasiveness and metastasis. Here, we aim to elucidate the roles of miRNAs, especially microRNA-4665-3p (miR-4665-3p), in the inhibitory effect of arsenic sulfide in gastric cancer (GC).

Methods

The arsenic sulfide-induced miRNA expression alterations in AGS cells was determined by miRNA microarray. RT-PCR was used to further verify the arsenic sulfide-regulated miRNAs in GC tissues. The inhibition of miR-4665-3p on the migration and invasion of GC cells were determined by wound healing assay and transwell assay. Western blot analysis was used to detect the expression of EMT related proteins and the putative target of miR-4665-3p.

Results

The miR-4665-3p was up-regulated by arsenic sulfide and showed inhibition upon the migration and invasion of GC cells. MiRBase and Western blotting indicated that miR-4665-3p directly down-regulated the oncoprotein GSE1. Morphological observation also indicated that the up-regulation of miR-4665-3p inhibits the EMT in GC cells.

Conclusion

Our data demonstrates that the increased expression of miR-4665-3p induced by arsenic sulfide suppresses the cell invasion, metastasis and EMT of GC cells, and has the potential to be a novel therapeutic target in GC.

Benchmarking life expectancy and cancer mortality: global comparison with cardiovascular disease 1981-2010

Objective To quantify the impact of cancer (all cancers combined and major sites) compared with cardiovascular disease (CVD) on longevity worldwide during 1981-2010.Design Retrospective demographic analysis using aggregated data.Setting National civil registration systems in member states of the World Health Organization.Participants 52 populations with moderate to high quality data on cause specific mortality.Main outcome measures Disease specific contributions to changes in life expectancy in ages 40-84 (LE40-84) over time in populations grouped by two levels of Human Development Index (HDI) values.Results Declining CVD mortality rates during 1981-2010 contributed to, on average, over half of the gains in LE40-84; the corresponding gains were 2.3 (men) and 1.7 (women) years, and 0.5 (men) and 0.8 (women) years in very high and medium and high HDI populations, respectively. Declines in cancer mortality rates contributed to, on average, 20% of the gains in LE40-84, or 0.8 (men) and 0.5 (women) years in very high HDI populations, and to over 10% or 0.2 years (both sexes) in medium and high HDI populations. Declining lung cancer mortality rates brought about the largest LE40-84 gain in men in very high HDI populations (up to 0.7 years in the Netherlands), whereas in medium and high HDI populations its contribution was smaller yet still positive. Among women, declines in breast cancer mortality rates were largely responsible for the improvement in longevity, particularly among very high HDI populations (up to 0.3 years in the United Kingdom). In contrast, losses in LE40-84 were observed in many medium and high HDI populations as a result of increasing breast cancer mortality rates.Conclusions The control of CVD has led to substantial gains in LE40-84 worldwide. The inequality in improvement in longevity attributed to declining cancer mortality rates reflects inequities in implementation of cancer control, particularly in less resourced populations and in women. Global actions are needed to revitalize efforts for cancer control, with a specific focus on less resourced countries.

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.

Long non-coding antisense RNA KRT7-AS is activated in gastric cancers and supports cancer cell progression by increasing KRT7 expression

Alterations in long non-coding RNAs (lncRNAs) are associated with human carcinogenesis. One group of lncRNAs, which are antisense in orientation to coding mRNAs (ASs), have been recently described in cancers but are poorly understood. We sought to identify ASs involved in human gastric cancer (GC) and to elucidate their mechanisms of action in carcinogenesis. We performed massively parallel RNA sequencing in GCs and matched normal tissues, as well as in GC-derived and normal gastric epithelial cell lines. One AS, designated Homo sapiens keratin 7 (KRT7-AS), was selected due to its marked upregulation and concordant expression with its cognate sense counterpart, KRT7, in GC tissues and cell lines. KRT7-AS formed an RNA-RNA hybrid with KRT7 and controlled KRT7 expression at both the mRNA and the post-transcriptional levels. Moreover, forced overexpression of the KRT7-overlapping region (OL) of KRT7-AS (but not its non-KRT7-OL portions) increased keratin 7 protein levels in cells. Finally, forced overexpression of full-length KRT7-AS or OL KRT7-AS (but not its non-KRT7-OL regions) promoted GC cell proliferation and migration. We conclude that lncRNA KRT7-AS promotes GC, at least in part, by increasing KRT7 expression.

Helicobacter pylori colonization in Nepal; assessment of prevalence and potential risk factors in a hospital-based patient cohort

Background

Helicobacter pylori, a gram-negative bacterium, can cause gastritis, peptic and duodenal ulcers. It is considered an important public health problem for both developed and developing world. This bacterium is classified as the class 1 carcinogen because it can cause cancer.

Methods

A hospital based study was conducted at Chitwan Medical College Teaching Hospital (CMCTH) from May to October 2014. Stool samples were collected from the suspected patients and were subjected to detection of the H. pylori stool antigen (HpSAg) following the procedures recommended by the manufacturer. A standard questionnaire on the potential risk factors was also designed and completed.

Result

HpSAg was detected in 16 % of suspected patients. The children up to 10 years of age were found to be highly infected (36 %). The patients living in urban area were found more susceptible to develop H. pylori infection (P < 0.05). Tea drinking and repeated eating habit (more than twice a day) were listed as the important factors that can limit the H. pylori infections significantly (P < 0.05).

Conclusion

In this hospital based study, a significant rate of prevalence was evaluated. However, we recommend a community based extensive study to reveal the real scenario of H. pylori infection in Nepalese populations.

Landscape of dietary factors associated with risk of gastric cancer: A systematic review and dose-response meta-analysis of prospective cohort studies

BACKGROUND

The associations between dietary factors and gastric cancer risk have been analysed by many studies, but with inconclusive results. We conducted a meta-analysis of prospective studies to systematically investigate the associations.

METHODS

Relevant studies were identified through searching Medline, Embase, and Web of Science up to June 30, 2015. We included prospective cohort studies of intake of dietary factors with risk estimates and 95% confidence intervals for gastric cancer.

RESULTS

Seventy-six prospective cohort studies were eligible and included in the analysis. We ascertained 32,758 gastric cancer cases out of 6,316,385 participants in relations to intake of 67 dietary factors, covering a wide ranging of vegetables, fruit, meat, fish, salt, alcohol, tea, coffee, and nutrients, during 3.3 to 30 years of follow-up. Evidence from this study indicates that consumption of total fruit and white vegetables, but not total vegetables, was inversely associated with gastric cancer risk. Both fruit and white vegetables are rich sources of vitamin C, which showed significant protective effect against gastric cancer by our analysis too. Furthermore, we found concordant positive associations between high-salt foods and gastric cancer risk. In addition, a strong effect of alcohol consumption, particularly beer and liquor but not wine, on gastric cancer risk was observed compared with nondrinkers. Dose-response analysis indicated that risk of gastric cancer was increased by 12% per 5 g/day increment of dietary salt intake or 5% per 10 g/day increment of alcohol consumption, and that a 100 g/day increment of fruit consumption was inversely associated with 5% reduction of risk.

CONCLUSION

This study provides comprehensive and strong evidence that there are a number of protective and risk factors for gastric cancer in diet. Our findings may have significant public health implications with regard to prevention of gastric cancer and provide insights into future cohort studies and the design of related clinical trials.

Hyperglycemia Promotes Human Gastric Carcinoma Progression via Aquaporin 3

BACKGROUND

Hyperglycemia plays an important role in the development of gastric carcinoma (GC). Aquaporin 3 (AQP3) is overexpressed in GC and involved in carcinogenesis and progression of GC. Hyperglycemia promotes AQP3 expression in human peritoneal mesothelial cells.

AIMS

To investigate whether hyperglycemia promotes progression of GC via AQP3.

METHODS

We enrolled 978 patients with GC and evaluated the correlation between preoperative fasting plasma glucose and clinicopathological features. AQP3 was detected by immunohistochemistry in human GC specimens. Western blotting and real-time quantitative polymerase chain reaction evaluated changes in AQP3 expression in human GC MGC803 and SGC7901 cells after co-culture with high glucose. Transwell migration and Cell Counting Kit-8 assays were used to determine migration and proliferation of GC cells.

RESULTS

Hyperglycemia (fasting plasma glucose ≥6.1 mM) correlated with tumor size, location, and pTNM stage. AQP3 expression in tumor tissue was associated with fasting plasma glucose levels. High glucose concentration upregulated AQP3 expression in a dose- and time-dependent manner. High glucose concentration promoted GC cell migration markedly, and AQP3 knockdown with siRNA could abolish the increase in cell migration. However, high glucose concentration inhibited cell proliferation, and AQP3 knockdown significantly enhanced the inhibitory effect of high glucose. The ERK and PI3K/AKT signaling pathways were involved in high glucose regulation of AQP3 in human GC cells.

CONCLUSION

Hyperglycemia promotes GC progress via AQP3. This improves our understanding of the mechanism of hyperglycemia-induced carcinogenesis and provides a potential therapeutic strategy for GC.

Salt processed food and gastric cancer in a Chinese population

To investigate the association between salt processed food and gastric cancer, a hospital based case-control study was conducted in a high risk area of China. One hundred and seven newly diagnosed cases with histological confirmation of gastric cancer and 209 controls were recruited. Information on dietary intake was collected with a validated food frequency questionnaire. Unconditional logistic regression was applied to estimate the odds ratios with adjustment for other potential confounders. Comparing the high intake group with never consumption of salt processed foods, salted meat, pickled vegetables and preserved vegetables were significantly associated with increased risk of gastric cancer. Meanwhile, salt taste preference in diet showed a dose-response relationship with gastric cancer. Our results suggest that consumption of salted meat, pickled and preserved vegetables, are positively associated with gastric cancer. Reduction of salt and salt processed food in diets might be one practical measure to preventing gastric cancer.

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.

Diet, Helicobacter pylori strain-specific infection, and gastric cancer risk among Chinese men

Evidence for the association of diet and gastric cancer is equivocal, and the majority of previous studies have not evaluated the interaction of diet and infection with Helicobacter pylori, the leading risk factor for gastric cancer. We examined these associations among 226 cases and 451 controls nested within a prospective cohort. Dietary intakes were calculated from validated food frequency questionnaires. Blood levels of 15 antibodies to Helicobacter pylori proteins were assessed using multiplex serology. Odds ratios (ORs) were calculated using logistic regression. Among individuals infected with high-risk Helicobacter pylori (sero-positivity to 5-6 virulent H. pylori proteins), increasing intake of red meat, heme iron, and sodium increased risk (comparing highest tertile to lowest: ORs [95% confidence interval {CI}]: 1.85 [1.01-3.40]; 1.95 [1.06-3.57]; and 1.76 [0.91-3.43], respectively) while increasing intake of fruit decreased gastric cancer risk (comparing highest tertile of intake to lowest: OR [95% CI]: 0.52 [0.28-0.94]). No associations of diet with risk were found among individuals infected with low-risk H. pylori (P for interaction for red meat and sodium: 0.02 and 0.01, respectively). In this population with over 90% prevalence of CagA-positive H. pylori infection, categorizing individuals using H. pylori multiplex serology may identify individuals for whom a diet intervention may be effective.

Consumption of fruit, but not vegetables, may reduce risk of gastric cancer: results from a meta-analysis of cohort studies

BACKGROUND AND AIMS

Quantification of the association between consumption of fruit and vegetables and risk of gastric cancer (GC) is controversial. We aimed to conduct a meta-analysis of cohort studies to evaluate the associations.

METHODS

Eligible studies published up to 31st August 2013 were retrieved via both computer searches of PubMed and EMBASE and a manual review of references. Random-effects models were used to calculate summary relative risk (SRR). Heterogeneity among studies was assessed using Cochran's Q and I(2) statistics.

RESULTS

A total of 17 articles (24 studies), were included in this meta-analysis. There were >2.4 million individuals (6632 GC events) with a median follow-up of 10years. Based on the high versus low analysis, consumption of fruit, but not vegetables, may reduce risk of gastric cancer (fruit: SRR=0.90, 95% confidence interval (CI): 0.83-0.98, Pheterogeneity=0.450; vegetable: SRR=0.96, 95% CI: 0.88-1.06, Pheterogeneity=0.150). Meta regression analysis suggested that outcome (incidence versus mortality) and study quality (high versus low) contributed significantly to heterogeneity. The same results were also shown in the linear dose-response analysis (per 100-g/day) (fruit: SRR=0.95, 95% CI: 0.91-0.99; vegetable: SRR=0.96, 95% CI: 0.91-1.01). Significant inverse associations emerged in non-linear models for consumption of fruit (Pnon-linearity=0.04), but not for consumption of vegetables (Pnon-linearity=0.551).

CONCLUSIONS

Findings from this meta-analysis indicate a significant protective effect for the consumption of fruit on GC risk, but not for the consumption of vegetables.

Interaction between dietary factors and Helicobacter pylori infection in noncardia gastric cancer: a population-based case-control study in China

BACKGROUND

The aim of this study was to investigate the relationships among Helicobacter pylori, dietary factors, and the risk of noncardia gastric cancer in a hospital-based case-control study in China.

METHODS

A case-control study of noncardia gastric cancer was performed at 3 hospitals in Xi'an, China, between September 2008 and July 2010. Participants were 257 men and women with histologically diagnosed primary noncardia gastric cancer and 514 sex- and age-matched (± 5 years) control subjects selected from the communities where the cases were living when diagnosed. A questionnaire was used to obtain information regarding potential risk factors, including diet, and blood samples were obtained to examine H pylori infection status.

RESULTS

Positive H pylori status (odds ratio [OR], 3.2; 95% confidence interval [CI], 0.8-5.9) and high consumption of pickled foods (OR, 27.1; 95%, 8.7-79.1) appeared to increase the risk of noncardia gastric cancer, whereas high consumption of vegetables (OR, 0.3; 95% CI, 0.1-0.89), fruits (OR, 0.2; 95% CI, 0.09-0.81), and soya products (OR, 0.04; 95% CI, 0.01-0.3) appeared to decrease the risk. Consumption of meat, cereals, tubers, eggs, oils, nuts, fish, fresh fruit, and red meat was not clearly associated with risk. Effect modification was observed, such that a relatively high consumption of fruit and vegetables appeared to attenuate the association of H pylori with risk of noncardia gastric cancer (p < 0.05).

CONCLUSIONS

Our data suggest that noncardia gastric cancer is highly preventable through modifications in dietary habits. Given the prevalence of H pylori infection worldwide, information regarding potential interaction between H pylori and lifestyle factors in gastric cancer development, including the dietary factors examined in our study, may prove valuable in future efforts at prevention.

MicroRNAs in pathogenesis, diagnosis, and treatment of gastroesophageal cancers

The incidence of gastroesophageal cancers is increasing each year, but despite much research, their molecular mechanisms are incompletely understood. microRNAs (miRNAs) are noncoding RNAs that have been associated with gastroesophageal carcinogenesis. We review the involvement of miRNAs in gastric and esophageal cancers and their mechanisms of regulation, effects on gene expression, and biological functions. Many miRNAs are dysregulated in gastroesophageal cancer cells via alterations in transcription, epigenetic features, or copy number of the genes that encode them. Each type of gastroesophageal tumor has a unique gene expression profile. miRNAs contribute to gastroesophageal carcinogenesis by altering expression of oncogenes and tumor suppressors to affect cell proliferation, apoptosis, and motility and invasion. A number of miRNAs, including circulating miRNAs, have been associated with tumor type or stage, or patient survival, and might be developed as diagnostic or prognostic markers. Greater understanding of the roles of miRNAs in gastroesophageal carcinogenesis could provide insights into the mechanisms of tumor development and identify therapeutic targets.

Trends of stomach cancer mortality in Eastern Asia in 1950-2004: comparative study of Japan, Hong Kong and Singapore using age, period and cohort analysis

To characterize the temporal trends of stomach cancer mortality in Eastern Asia and to better interpret the causes of the trends, we performed age, period and cohort analysis (APC analysis) on the mortality rates in Japan, Hong Kong and Singapore during 1950-2004, as well as the rates in the US as a control population. For the APC analysis, Holford's approach was used to avoid the identification problem. Age-standardized mortality rates (ASMR) decreased consistently in all four areas during the observation period in both males and females. Japan had the highest ASMR in both sexes, followed by Singapore, Hong Kong and the US, but the differences in ASMR among the four areas diminished with time. The results of APC analysis suggested that the decreasing mortality rates in Eastern Asia were caused by the combination of decreasing cohort effect since the end of the 1800s and decreasing period effect from the 1950s. The US showed similar results, but its decreases in the period and cohort effect preceded those of Eastern Asia. Possible causes for the decrease in the cohort effect include improvement in the socioeconomic conditions during childhood and a decrease in the prevalence of H. pylori infection, while possible causes for the decrease in the period effect include a decrease in dietary salt intake and improvements in cancer detection and treatment. These findings may help us to predict future changes in the mortality rates of stomach cancer.

Effect of folic acid supplementation on oxidative gastric mucosa damage and acid secretory response in the rat

Objective:

This study investigated the antioxidative and antisecretory properties of folic acid in the rats’ stomach.

Materials and Methods:

Male Wistar rats were treated with 2 mg/kg diet of folic acid for 21 days. Gastric ulceration was induced by indomethacin, scored, and assayed to determine the concentration of total protein, mucus, malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD) in homogenized samples. Normal saline and Ranitidine treated group served as negative and positive control, respectively. Basal and stimulated acid secretion was measured by continuous perfusion method.

Result:

Indomethacin caused severe damage to the rats’ stomach with an ulcer index of 4.32 ± 0.13, increase in MDA concentration and reduction in the concentration of protein, mucus, catalase and superoxide dismutase (P < 0.001). Pre-treatment with folic acid prevented the formation of ulcers by 32%, and attenuated the inhibition of mucus by 14%, CAT, 51% and SOD, 150%. Ranitidine afforded 56% prevention in ulcer formation with 67%, 55% and 78% attenuation of the inhibition of mucus, CAT and SOD, respectively, by indomethacin. While indomethacin-induced lipid peroxidation was attenuated by 58% reduction in MDA concentration on pretreatment with folic acid, Ranitidine offered 65% reduction. Basal and stimulated acid secretions were significantly reduced in the treated when compared with control animals. Folic acid produced a 21% reduction in the basal acid output when compared with the control animals (P < 0.05), and 140% reduction in histamine-induced acid response.

Conclusion:

The results indicate the gastroprotective activity of folic acid due its antioxidative and anti-secretory properties.

Comparative epidemiology of gastric cancer between Japan and China

AIM

To clarify the similarities and differences in gastric cancer epidemiology between Japan and China.

METHODS

A comprehensive literature search of the PubMed database was performed. The relevant literature published in China was also been cited. Data on incidence and mortality rates in 2008 were obtained from the Cancer Mondial database, published by International Agency for Research on Cancer at http://www-dep.iarc.fr/.

RESULTS

Gastric cancer remains a significant public health burden in both Japan and China. The prevalence of Helicobacter pylori (H. pylori) colonization is high in the adult populations of both countries. Accumulating evidence from intervention studies in both countries has shown the effectiveness of H. pylori eradication in reducing gastric cancer incidence. There are differences, however, in many aspects of gastric cancer, including patterns of incidence and mortality, trends in the prevalence of H. pylori infection, H. pylori strains, the magnitude of risk of gastric cancer related to H. pylori infection, and associations with dietary habits. Compared with China, Japan has seen a more rapid decline in H. pylori infection among adolescents. While Japanese cohort studies have dominated the literature concerning the associations between gastric cancer and dietary habits, numerous case-control studies in China suggest a positive association between a high intake of preserved fish and vegetables and gastric cancer risk. There is a need for a multidisciplinary research approach to understand the interactions between various strains of H. pylori, host factors, and other lifestyle and environmental factors in gastric carcinogenesis in both countries.

CONCLUSION

The shared high incidence of gastric cancer and high prevalence of H. pylori, as well as differences in many aspects of gastric cancer, provide an excellent opportunity to establish Sino-Japanese collaborations.

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.

Association between the TGFB1 -509C/T and TGFBR2 -875A/G polymorphisms and gastric cancer: a case-control study

The transforming growth factor-β (TGFβ) pathway plays an important role in various types of human cancer. However, the role of TGFB1 -509C/T and TGFBR2 -875A/G polymorphisms in gastric cancer is controversial. We aimed to investigate the associations between these polymorphisms and gastric cancer susceptibility, clinicopathological parameters and survival. A case-control study was conducted in 1,010 gastric cancer patients and 1,500 healthy controls. Genotypes were determined by PCR-restriction fragment length polymorphism and DNA sequencing. Compared with the TT genotype, the TGFB1 -509 C allele (CT/CC) was significantly associated with a reduced risk of gastric cancer (OR, 0.71; 95% CI, 0.58-0.87; p=0.001) and certain subtypes of gastric cancer including intestinal type (OR, 0.70; 95% CI, 0.57-0.87; p=0.001), poorly differentiated (OR, 0.67; 95% CI, 0.54-0.85; p=0.001) and stage TNM III+IV (OR, 0.73; 95% CI, 0.58-0.92; p=0.008). Compared with the TGFBR2 -875 GG genotype, carriers of the A allele (AA/AG) had a significantly decreased gastric cancer risk (OR, 0.58; 95% CI, 0.62-0.91; P<0.001). A combination of the TGFB1 -509 C and TGFBR2 -875 A alleles was associated with a further decreased risk of gastric cancer (OR, 0.42; 95% CI, 0.32-0.57, p<0.001). No significant correlation was observed between polymorphisms and survival of gastric cancer patients. Our results suggest that both the TGFB1 -509 and TGFBR2 -875 polymorphisms contribute to a decreased gastric cancer risk. The TGFB1 -509 polymorphism affects certain subtypes of gastric cancer according to clinicopathological parameters. A combination of the TGFB1 -509 C and TGFBR2 -875 A alleles conferred a further decreased gastric cancer risk. These findings provide clues to the biological mechanisms that underline tumor heterogeneity.

Gastric cancer: an infectious disease

The role of infectious agents and chronic inflammation in carcinogenesis is being increasingly recognized. It has been estimated that about 18% of cancers are directly linked to infections, particularly gastric adenocarcinoma (Helicobacter pylori), cervical carcinoma (human papilloma viruses), and hepatocarcinoma (hepatitis B and C viruses). Multiple clinical trials of COX-2 inhibitors and other antiinflammatory agents have shown a beneficial effect on the development of diverse tumors, such as those of the colon, stomach, prostate, and breast. However, their mechanism of action is not completely understood and may differ among the infectious agents and tumor types. Because gastric adenocarcinomas account for more than 90% of all gastric malignancies, this review focuses on adenocarcinomas.

MicroRNA dysregulation in gastric cancer: a new player enters the game

Gastric carcinogenesis is a multistep process involving genetic and epigenetic alteration of protein-coding proto-oncogenes and tumor-suppressor genes. Recent discoveries have shed new light on the involvement of a class of noncoding RNA known as microRNA (miRNA) in gastric cancer. A substantial number of miRNAs show differential expression in gastric cancer tissues. Genes coding for these miRNAs have been characterized as novel proto-oncogenes and tumor-suppressor genes based on findings that these miRNAs control malignant phenotypes of gastric cancer cells. In this connection, miRNA dysregulation promotes cell-cycle progression, confers resistance to apoptosis, and enhances invasiveness and metastasis. Moreover, certain polymorphisms in miRNA genes are associated with increased risks for atrophic gastritis and gastric cancer, whereas circulating levels of miRNAs may serve as biomarkers for early diagnosis. Several miRNAs have also been shown to correlate with gastric cancer progression, and thus may be used as prognostic markers. Elucidating the biological aspects of miRNA dysregulation may help us better understand the pathogenesis of gastric cancer and promote the development of miRNA-directed therapeutics against this deadly disease.

Dysregulation of cellular signaling in gastric cancer

The pathogenesis of gastric cancer is complex and related to multiple factors. Dysregulation of intracellular signaling pathways represents a common pathogenic mechanism and may be amenable to drug targeting. Multiple well-established oncogenic pathways, such as those mediated by cell cycle regulators, nuclear factor-kappaB, cyclooxygenase-2 and epidermal growth factor receptor are implicated in gastric carcinogenesis. Emerging evidence also underscores the importance of signaling pathways involved in the developmental process, including transforming growth factor-beta/bone morphogenetic protein signaling, Wnt/beta-catenin signaling, Hedgehog signaling and Notch signaling. Understanding their biological significance will provide a rational basis for drug development. Their relative importance and cross-talk in gastric carcinogenesis, however, are still not completely understood and warrant further investigation.

IL-1B-511 polymorphism is associated with increased risk of certain subtypes of gastric cancer in Chinese: a case-control study

OBJECTIVES

The association of interleukin-1B (IL-1B)-511 polymorphism with gastric cancer is still controversial, and the association of IL-1B-511 polymorphism with subtypes of gastric cancer is still largely unknown. We investigated whether the association between IL-1B-511 polymorphism and gastric cancer risk varies by clinically important tumor characteristics and the prognostic value of this polymorphism in a large population-based case-control study among Chinese.

METHODS

A population-based case-control study was conducted between 1999 and 2006 in Guangdong Province, China. A total of 1,010 gastric cancer patients and 1,500 healthy controls were enrolled in this study. Polymorphism in IL-1B-511 was analyzed by PCR-restriction fragment length polymorphism on 501 gastric cancers and 500 healthy controls.

RESULTS

Compared with the CC genotype, carriers of IL-1B-511 TT genotype had an increased gastric cancer risk (odds ratio (OR)=1.97, 95% confidence interval (CI)=1.29-3.01, P=0.0016). TT genotype was significantly associated with intestinal type of gastric cancer (OR=3.16, 95% CI=1.74-5.71, P=0.0001) but not with diffuse or mixed-type gastric cancer. The test for OR heterogeneity between the intestinal-type and non-intestinal-type gastric cancers was statistically significant (P=0.02). In subgroup analyses, TT genotype was found to be associated with poorly differentiated gastric cancer (OR=3.31, 95% CI=1.43-3.60, P<0.0001), but not with moderately or well-differentiated gastric cancer. IL-1B-511 genotypes were not associated with the prognosis of gastric cancer patients.

CONCLUSIONS

IL-1B polymorphism influences certain subtypes of gastric cancer according to the clinical and pathological features. Understanding the etiologic heterogeneity of gastric cancer may result in improvements in controlling this disorder.

Helicobacter pylori's unconventional role in health and disease

The discovery of a bacterium, Helicobacter pylori, that is resident in the human stomach and causes chronic disease (peptic ulcer and gastric cancer) was radical on many levels. Whereas the mouth and the colon were both known to host a large number of microorganisms, collectively referred to as the microbiome, the stomach was thought to be a virtual Sahara desert for microbes because of its high acidity. We now know that H. pylori is one of many species of bacteria that live in the stomach, although H. pylori seems to dominate this community. H. pylori does not behave as a classical bacterial pathogen: disease is not solely mediated by production of toxins, although certain H. pylori genes, including those that encode exotoxins, increase the risk of disease development. Instead, disease seems to result from a complex interaction between the bacterium, the host, and the environment. Furthermore, H. pylori was the first bacterium observed to behave as a carcinogen. The innate and adaptive immune defenses of the host, combined with factors in the environment of the stomach, apparently drive a continuously high rate of genomic variation in H. pylori. Studies of this genetic diversity in strains isolated from various locations across the globe show that H. pylori has coevolved with humans throughout our history. This long association has given rise not only to disease, but also to possible protective effects, particularly with respect to diseases of the esophagus. Given this complex relationship with human health, eradication of H. pylori in nonsymptomatic individuals may not be the best course of action. The story of H. pylori teaches us to look more deeply at our resident microbiome and the complexity of its interactions, both in this complex population and within our own tissues, to gain a better understanding of health and disease.

Hyperglycemia increases risk of gastric cancer posed by Helicobacter pylori infection: a population-based cohort study

BACKGROUND & AIMS

Although diabetes mellitus and hyperglycemia are considered to be possible risk factors for various types of malignancy, the epidemiologic evidence concerning gastric cancer is scarce. The aim of this study was to evaluate the impact of hemoglobin A1c (HbA1c) levels on gastric cancer occurrence and their interaction with Helicobacter pylori infection.

METHODS

A total of 2603 Japanese subjects aged>or=40 years were stratified into 4 groups according to baseline HbA1c levels (<or=4.9%, 5.0%-5.9%, 6.0%-6.9%, and >or=7.0%) and followed up prospectively for 14 years.

RESULTS

During the follow-up, 97 subjects developed gastric cancer. The age- and sex-adjusted incidence of gastric cancer significantly increased in the 6.0%-6.9% (5.1 per 1000 person-years; P<.05) and >or=7.0% groups (5.5 per 1000 person-years; P<.05) compared with the 5.0%-5.9% group (2.5 per 1000 person-years), whereas it was slightly but not significantly high in the <or=4.9% group (3.6 per 1000 person-years). This association remained substantially unchanged even after adjusting for the confounding factors including Helicobacter pylori seropositivity, (multivariate-adjusted hazard ratio [HR], 2.13; 95% confidence interval [CI]: 1.30-3.47 for the 6.0%-6.9% group and HR, 2.69; 95% CI: 1.24-5.85 for the >or=7.0% group). Among subjects who had both high HbA1c levels (>or=6.0%) and Helicobacter pylori infection, the risk of gastric cancer was dramatically elevated (interaction term, P=.004).

CONCLUSIONS

Our findings suggest that casual hyperglycemia is a risk factor for gastric cancer and is a possible cofactor increasing the risk posed by Helicobacter pylori infection.

Effects of amodiaquine hydrochloride and artemisinin on indomethacin-induced lipid peroxidation in rats

In this study, the effects of two antimalarials-amodiaquine hydrochloride and artemisinin were investigated in ulcerated albino rats of Wistar strain. Rats were treated with amodiaquine (30 mg kg(-1)) and Artemisinin (2.86 mg kg(-1)) for 24 h after formation of ulcers induced by indomethacin. Treatments with Amodiaquine Hydrochloride led to significantly increased gastric lesions while artemisinin led to significantly decreased gastric lesions. Also, amodiaquine hydrochloride seemed to elaborate the indomethacin induced effects on gastric juice volume, pH and acid output, while artemisinin attenuated these changes. The data indicates that the use of amodiaquine hydrochloride may be dangerous to the integrity of the stomach, especially in existing gastric ulcers, while artemisinin is mild and ameliorating, may result from their lipid peroxidation/apoptosis activity interference.

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.

Autoimmune responses induced by Helicobacter pylori improve the prognosis of gastric carcinoma

Gastric carcinoma (GC) remains one of most serious malignant tumors worldwide, with Helicobacter pylori being the definite carcinogen. The H. pylori components, cytotoxin-associated gene A (CagA), vacuolating toxin A (VacA) and blood-group antigen-binding adhesin gene (BabA), can mimic and bind to specific receptors or surface molecules both on gastric epithelial cells and platelets, in which CagA and VacA may also be directly involved in loosening of tight junctions in monolayers of polarized gastric epithelial cells. It has been shown that a history of H. pylori infection is found in the majority of patients with GC, and that anti-CagA, anti-VacA and anti-BabA antibodies targeting both H. pylori components and host mimic molecules can be detected in them with increased levels. Patients with GC who are positive for H. pylori prospectively have a better outlook than those negative. The stimulation of mentioned autoantibodies in antigen processing and presentation and subsequent T-cell activation and proliferation improves host immune status. On the other hand, in an autoimmune response, autoantibodies can induce the cross-reaction against those localized or circulating GC cells, which are characterized by mimic or absorbed H. pylori antigens, and lead to the killing and even suppressing of metastasis of cancer cells. Therefore, we here hypothesize that autoimmune responses induced by H. pylori components may play a key role in improving the prognosis of patients with gastric carcinoma.

Critical role of Helicobacter pylori in the pattern of gastritis and carditis in residents of an area with high prevalence of gastric cardia cancer

We have investigated the role of Helicobacter pylori infection and of other risk factors of gastritis and carditis in residents of a high-risk area for gastric cardia cancer. During a national population-based endoscopic survey, 508 randomly-selected participants aged > or =40 were enrolled. Mucosal biopsies were obtained from six standard sites. Polymorphonuclear (PMN) and mononuclear (MN) infiltration and combined inflammatory scores (CIS) for chronic gastritis and H.pylori were assessed. Relationships of H.pylori and reflux esophagitis with these variables were calculated for cardia and non-cardia subsites. Both PMN and MN infiltrations correlated strongly with H.pylori infection. For PMN the relationship was maximum for the antrum (odds ratio (OR) = 9.4 (5.2-17.1)) and minimum for the gastric body (OR = 1.7 (1.0-2.9)). There was a significant relationship between carditis and H.pylori (OR = 2.8 (1.7-4.9)). A similar relationship was obtained for MN infiltration. In 56% of subjects the mean MN score for the corpus was equal to or greater than that for the antrum. For 59% of subjects the MN score for the cardia was greater than or equal to the antral score. Use of logistic regression revealed that was the main risk factor for gastritis and carditis in all sites. There was an inverse relationship between reflux esophagitis and carditis. H.pylori is the main risk factor for gastritis for all sites of the stomach including the cardia; but this relationship is stronger for the antrum and cardia than for the body. Continuous cardia inflammation may contribute to the high incidence of gastric cardia cancer in this region.

Toxicological evaluation of some Malaysian locally processed raw food products

Malaysian locally processed raw food products are widely used as main ingredients in local cooking. Previous studies showed that these food products have a positive correlation with the incidence of cancer. The cytotoxicity effect was evaluated using MTT assay (3-(4,5-dimetil-2-thiazolil)-2,5-diphenyl-2H-tetrazolium bromide) against Chang liver cells at 2000 microg/ml following 72 h incubation. Findings showed all methanol extracts caused a tremendous drop in the percentage of cell viability at 2000 microg/ml (shrimp paste - 41.69+/-3.36%, salted fish - 37.2+/-1.06%, dried shrimp - 40.32+/-1.8%, p<0.05). To detect DNA damage in a single cell, alkaline Comet Assay was used. None of the extracts caused DNA damage to the Chang liver cells at 62.5 microg/ml following 24 h incubation, as compared to the positive control, hydrogen peroxide (tail moment - 9.50+/-1.50; tail intensity - 30.50+/-2.50). Proximate analysis which was used for the evaluation of macronutrients in food showed that shrimp paste did not comply with the protein requirement (<25%) as in Food Act 1983. Salt was found in every sample with the highest percentage being detected in shrimp paste which exceeded 20%. Following heavy metal analysis (arsenic, cadmium, lead and mercury), arsenic was found in every sample with dried shrimps showing the highest value as compared to the other samples (6.16 mg/kg). In conclusion, several food extracts showed cytotoxic effect but did not cause DNA damage against Chang liver cells. Salt was found as the main additive and arsenic was present in every sample, which could be the probable cause of the toxicity effects observed.

Lead exposure increases oxidative stress in the gastric mucosa of HCl/ethanol-exposed rats

AIM: To investigate the role of reactive oxygen species in the ulcer-aggravating effect of lead in albino rats.

METHODS: Albino Wistar rats were randomly divided into three groups and treated orally with 100 mg/L (low dose) or 5000 mg/L (high dose) of lead acetate for 15 wk. A third group received saline and served as control. At the end of wk 15, colorimetric assays were applied to determine the concentrations of total protein and nitrite, the activities of the oxidative enzymes catalase and superoxide dismutase, and lipid peroxidation in homogenized gastric mucosal samples.

RESULTS: Exposure of rats to lead significantly increased the gastric mucosal damage caused by acidified ethanol. Although the basal gastric acid secretory rate was not significantly altered, the maximal response of the stomach to histamine was significantly higher in the lead-exposed animals than in the unexposed control group. Exposure to low and high levels of lead significantly increased gastric lipid peroxidation to 183.2% ± 12.7% and 226.1% ± 6.8% of control values respectively (P < 0.0). On the other hand, lead exposure significantly decreased catalase and superoxide dismutase (SOD) activities and the amount of nitrite in gastric mucosal samples.

CONCLUSION: Lead increases the formation of gastric ulcers by interfering with the oxidative metabolism in the stomach.

Feasibility and cost-effectiveness of using magnification chromoendoscopy and pepsinogen serum levels for the follow-up of patients with atrophic chronic gastritis and intestinal metaplasia

BACKGROUND

The follow-up of patients with atrophic chronic gastritis or intestinal metaplasia may lead to early diagnosis of gastric cancer. However, to-date no cost-effective model has been proposed. Improved endoscopic examination using magnification chromoendoscopy together with non-invasive functional assessment with pepsinogen serum levels are accurate in the diagnosis of intestinal metaplasia (extension) and minute dysplastic lesions. The aim of this study was to assess the feasibility and cost-effectiveness of a follow-up model for patients with atrophic chronic gastritis and intestinal metaplasia based on gastric mucosal status using magnification chromoendoscopy and pepsinogen.

METHODS

A cohort of patients with lesions as severe as atrophic chronic gastritis were followed-up according to a standardized protocol using magnification chromoendoscopy with methylene blue and measurement of serum pepsinogen I and II levels. A single node decision tree and Markov chain modeling were used to define cost-effectiveness of this follow-up model versus its absence. Transition rates were considered time-independent and calculated using primary data following cohort data analysis. Costs, quality of life and survival were estimated based on published data and extensive sensitivity analysis was performed.

RESULTS

A total of 100 patients were successfully followed-up over 3 years. Seven cases of dysplasia were diagnosed during follow-up, all among patients with incomplete intestinal metaplasia at baseline, six of whom had extensive (pepsinogen I to II ratio <3) incomplete intestinal metaplasia. For those individuals with atrophic chronic gastritis or complete intestinal metaplasia, a yearly measurement of pepsinogen levels or an endoscopic examination on a 3-yearly basis would cost 455 euros per quality-adjusted life year (QALY) gain. Endoscopic examination and pepsinogen serum level measurement on a yearly basis would cost 1868 euros per QALY for patients with extensive intestinal metaplasia.

CONCLUSIONS

The follow-up of patients with atrophic chronic gastritis or intestinal metaplasia is both feasible and cost-effective if improved accurate endoscopic examination of gastric mucosa together with non-invasive assessment of gastric mucosal status are used to identify individuals at high-risk for development of gastric cancer.

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

Despite decreasing incidence and mortality rates, gastric cancer (GC) still remains the fourth most common cancer and the second most common cause of cancer-related deaths worldwide. Due to the limited treatment options, at present, prevention is likely to be the only effective means of controlling this disease. The success of a prevention strategy depends upon the understanding of etiological and pathogenic mechanisms underlying gastric carcinogenesis. The etiology of GC is multi-factorial, however, in the recent years, mounting evidence suggests that environmental factors play a key role. The most important environmental factors implicated in the pathogenesis of GC are diet and H pylori infection. Thus, modifications in lifestyle and dietary habit associated with eradication of H pylori infection could hypothetically represent the most promising potential targets for GC prevention. In this review we will address the evidence and the controversies on the role of these agents in non-cardia GC by focusing on retrospective and prospective observational studies and interventional trials.

Salt and stress synergize H. pylori-induced gastric lesions, cell proliferation, and p21 expression in Mongolian gerbils

Our aim was to determine if salt and stress enhance Helicobacter pylori (Hp) lesions in Meriones unguiculatus. Two hundred seventy-eight pathogen-free gerbils were allocated to seven groups: Hp-Sydney strain (45), 8% higher-salt diet (38), stress (60% space reduction/water immersion; 36), Hp + salt (33), Hp + stress (34), N-methyl-N-nitro-N-nitrosoguanidine (34), and sham (58). Gerbils were sacrificed at 1 week (67), 12 weeks (73), 52 weeks (65), and 68 weeks (73). Sydney, Padova, and Lauren classifications were blindly used. Proliferation, p53, p21, and apoptosis were assessed. Follicular active gastritis (grade 2/3) was observed in 10% of Hp gerbils, 38% of Hp + salt gerbils, and 29% of Hp + stress gerbils at 52 weeks and 67%, 83%, and 43% at 68 weeks (P < 0.05). Heterotopic proliferative glands were identified in synergy groups from 52 weeks, with increases in their number and size by 68 weeks. Higher proliferative rates were observed in Hp+salt gerbils (P < 0.0001), and p21 overexpression in Hp+salt and Hp+stress gerbils (both P's < 0.0001), by 68 weeks, without p53 increases. We conclude that salt and stress synergize Hp damage and increase pseudo-invasive gland foci.

A novel method for evaluation of improved survival trend for common cancer: early detection or improvement of medical care

RATIONALE, AIMS AND OBJECTIVES

The improvement of survival with time for cancers has been observed worldwide. However, whether and to what extent such an improvement is attributed to early detection or the advance in medical technology is barely addressed.

METHOD

We developed a novel graphic method to calculate attributable proportions related to two factors. This graphic method was first to calculate adjusted survival curve by the application of direct standardized epidemiological method to tumour staging. The crude survival curve was then compared with the adjusted survival curve.

RESULTS

Cumulative survival curves of two time epochs, 1989-1993 (period 1) and 1994-1998 (period 2), on six common cancers collected from cancer registry of National Taiwan University between 1989 and 1998, were compared. The attributable proportions due to early detection and medical care were 77% and 23% for breast cancer, 50% and 50% for cervical cancer, 52% and 48% for colorectal cancer, 76% and 24% for gastric cancer, 66% and 34% for liver cancer, and 30% and 70% for prostate cancer respectively.

CONCLUSION

Distinguishing between early detection from advance in medical care associated with the improvement of survival trend using our graphic method has a significant implication for secondary and tertiary prevention of common cancers.

Helicobacter pylori infection can modulate the susceptibility of gastric mucosa cells to MNNG

The pathogenesis of stomach cells can be associated with their susceptibility to exogenous dietary irritants, like nitrosamines such as dimethylnitrosamines (DMNA), and to the effects of non-dietary factors, including Helicobacter pylori infection. We used N-methyl-N’-nitro N-nitrosoguanidyne (MNNG) as a surrogate agent that induces a spectrum of DNA damage similar to DMNA. Using the alkaline comet assay, we showed that antioxidants — vitamins C and E, quercetin, and melatonin — reduced the genotoxic effect of MNNG in H. pylori-infected and non-infected human gastric mucosa cells (GMCs). To compare the sensitivity of the stomach and the blood, the experiment was also carried out in peripheral blood. We observed a higher level of DNA damage induced by MNNG in H. pylori-infected than in noninfected GMCs. We did not note any difference in the efficacy of the repair of the damage in either type of GMC. H. pylori infection may play an important role in the pathogenesis of GMCs, as it can modulate their susceptibility to dietary mutagens/carcinogens, thus contributing to gastric cancer.

Trends in stomach cancer mortality in relation to living conditions in childhood. A study among cohorts born between 1860 and 1939 in seven European countries

AIM

To assess whether secular trends in stomach cancer mortality were correlated with trends in infant mortality rate (IMR) or gross domestic product (GDP).

METHODS

Data from seven European countries were analyzed. We used Poisson regression to describe mortality trends among birth cohorts of 1865-1939 and correlation coefficients to determine associations with IMR/GDP.

RESULTS

Large differences were observed between birth cohorts in mortality from stomach cancer. In each country, these cohort differences were closely related to IMR/GDP levels at birth time. However, stronger associations were observed with measures of living conditions during later life. In comparisons between countries, stomach cancer mortality rates were not consistently related to national levels of IMR/GDP.

CONCLUSION

General living conditions in childhood do not seem to have had a predominant effect on secular trends in stomach cancer mortality. The mortality decline is likely to be related to more 1specific factors, such as declining Helicobacter pylori prevalence.

Helicobacter pylori infection causes gastric cancer? A review of the epidemiological, meta-analytic, and experimental evidence

Since the discovery of Campylobacter-like organisms Helicobacter pylori (H pylori) more than two decades ago the possibility of a relationship with gastric cancer has been postulated, tested and supposedly proven. There have been numerous human studies of various designs from many countries around the world. Several meta-analyses have been published and more recently a small number of experimental animal studies were reported looking at the association between H pylori infection and gastric cancer. Over the years, the human epidemiological studies have produced conflicting results; the meta-analyses have as one would expect produced similar pooled estimates; while the early experimental animal studies require replication. The exact mechanisms by which H pylori might cause gastric cancer are still under investigation and remain to be elucidated.

Risk factor analysis for metaplastic gastritis in Koreans

AIM: To conduct a retrospective study to determine the risk factors for development of metaplastic gastritis in Korean population.

METHODS: The database of 113 449 subjects who underwent a gastroscopy for the purpose of a regular check-up at center for health promotion, Samsung medical center during 5 years was collected and retrospectively analyzed. Among them, 5 847 subjects who had endoscopically diagnosed as a metaplastic gastritis or 10 076 normal as well as answered to questionnaire were included for present study. The subjects were divided into 2 groups; Group I, normal and Group II, metaplastic gastritis. Age, gender, Helicobacter pylori (H pylori) seropositivity, body mass index (BMI), family history of cancer, smoking, alcohol consumption, total daily calories, folate and salt intake and dietary habit (out-eating, overeating, irregular eating) were retrieved from questionnaire or electronic medical record and compared between group I and group II.

RESULTS: The prevalence of group II was 11% (13 578/113 449) increasing its prevalence with age (P = 0.000). But, there was no significant association between 2 groups in BMI, family history of cancer, alcohol consumption, total daily calories, folate and salt intake and dietary habit (out-eating, overeating, irregular eating). Old age (P = 0.000), male gender (P = 0.000), H pylori seropositivity (P = 0.010) and current smoker (P = 0.000) were significantly more common in group II at multiple logistic regression model.

CONCLUSION: Our data suggested that old age, male gender, H pylori seropositivity and smoking were risk factors for metaplastic gastritis, precancerous lesion of gastric cancer.