Nutrition and gastric cancer risk: an update

The role of tomato products and lycopene in the prevention of gastric cancer: a meta-analysis of epidemiologic studies

BACKGROUND

Gastric cancer is the second most common cause of death from cancer worldwide. Epidemiologic studies have examined the possible association between tomato products consumption and gastric cancer, but the relationship between tomato products and the risk of gastric cancer is controversial. We performed a meta-analysis of cohort and case-control studies to analyze this association.

METHODS

We systematically searched MEDLINE and EMBASE and contacted authors to identify potential studies published from January 1966 to June 2012. We pooled the relative risks from individual studies using a random-effects model and performed heterogeneity and publication bias analyses.

RESULTS

Twenty-one studies were eligible for our inclusion criteria, in a pooled analysis of all studies, consumption of large amounts of tomato products (in a comparison of the highest and lowest consumption groups) reduced the risk for gastric cancer (odds ratio, 0.73; 95% confidence interval, 0.60-0.90). The pooled OR of lycopene consumption and serum lycopene was 0.88 (95% CI=0.67-1.16) and 0.79 (95% CI=0.59-1.07), respectively.

CONCLUSIONS

Consumption of large amounts of tomato products is associated with a reduced risk of gastric cancer. However, because of potential confounding factors and exposure misclassification, further studies are required to establish these findings.

Management of localized gastric cancer

Gastric cancer continues to be a fatal disease with majority of cases presenting in late stages. For patients with advanced disease, we can only recommend palliative therapy. For localized gastric cancer, the approaches vary in various regions of the world. In western countries, preoperative chemotherapy or adjuvant chemo-radiation is preferred; however in Asia, surgery followed by adjuvant chemotherapy is favored. The extent of the lymph node dissection also varies by region. D2 gastrectomy is difficult to implement in most western countries while it is standardized and is a routine in Asia. We recommend multidisciplinary evaluation of each patient before starting any therapy. The prognosis after resection depends of the pathologic stage. Long-term survivors are often <50% in the West and <70% in many Asian countries. Regional and systemic recurrences are common. Improved systemic treatments are needed. Detailed studies of molecular biology might uncover novel therapeutic targets and prognostic subgroups.

A lowered salt intake does not compromise iodine status in Cape Town, South Africa, where salt iodization is mandatory

OBJECTIVE

Universal salt iodization is an effective strategy to optimize population-level iodine. At the same time as salt-lowering initiatives are encouraged globally, there is concern about compromised iodine intakes. This study investigated whether salt intakes at recommended levels resulted in a suboptimal iodine status in a country where salt is the vehicle for iodine fortification.

METHODS

Three 24-h urine samples were collected for the assessment of urinary sodium and one sample was taken for urinary iodine concentrations (UICs) in a convenience sample of 262 adult men and women in Cape Town, South Africa. Median UIC was compared across categories of sodium excretion equivalent to salt intakes lower than 5, 5 to 9, and greater than or equal to 9 g/d.

RESULTS

The median UIC was 120 μg/L (interquartile range 75.3-196.3), indicating iodine sufficiency. Less one-fourth (23.2%) of subjects had urinary sodium excretion values within the desirable range (salt <5 g/d), 50.7% had high values (5-9 g/d), and 22.8% had very high values (≥9 g/d). No association between urinary iodine and mean 3 × 24-h urinary sodium concentration was found (r = 0.087, P = 0.198) and UIC status did not differ according to urinary sodium categories (P = 0.804).

CONCLUSION

In a country with mandatory universal salt iodization, consumers with salt intakes within the recommended range (<5 g/d) are iodine replete, and median UIC does not differ across categories of salt intake. This indicates that much of the dietary salt is provided from non-iodinated sources, presumably added to processed foods.

Gastric cancer incidence and mortality is associated with altitude in the mountainous regions of Pacific Latin America

In Latin America, gastric cancer is a leading cancer, and countries in the region have some of the highest mortality rates worldwide, including Chile, Costa Rica, and Colombia. Geographic variation in mortality rates is observed both between neighboring countries and within nations. We discuss epidemiological observations suggesting an association between altitude and gastric cancer risk in Latin America. In the Americas, the burden of gastric cancer mortality is concentrated in the mountainous areas along the Pacific rim, following the geography of the Andes sierra, from Venezuela to Chile, and the Sierra Madre and Cordillera de Centroamérica, from southern Mexico to Costa Rica. Altitude is probably a surrogate for host genetic, bacterial, dietary, and environmental factors that may cluster in the mountainous regions. For example, H. pylori strains from patients of the Andean Nariño region of Colombia display European ancestral haplotypes, whereas strains from the Pacific coast are predominantly of African origin. The observation of higher gastric cancer rates in the mountainous areas is not universal: the association is absent in Chile, where risk is more strongly associated with the age of H. pylori acquisition and socio-economic determinants. The dramatic global and regional variations in gastric cancer incidence and mortality rates offer the opportunity for scientific discovery and focused prevention programs.

Gastric cancer incidence and mortality is associated with altitude in the mountainous regions of Pacific Latin America

In Latin America, gastric cancer is a leading cancer, and countries in the region have some of the highest mortality rates worldwide, including Chile, Costa Rica, and Colombia. Geographic variation in mortality rates is observed both between neighboring countries and within nations. We discuss epidemiological observations suggesting an association between altitude and gastric cancer risk in Latin America. In the Americas, the burden of gastric cancer mortality is concentrated in the mountainous areas along the Pacific rim, following the geography of the Andes sierra, from Venezuela to Chile, and the Sierra Madre and Cordillera de Centroamérica, from southern Mexico to Costa Rica. Altitude is probably a surrogate for host genetic, bacterial, dietary, and environmental factors that may cluster in the mountainous regions. For example, H. pylori strains from patients of the Andean Nariño region of Colombia display European ancestral haplotypes, whereas strains from the Pacific coast are predominantly of African origin. The observation of higher gastric cancer rates in the mountainous areas is not universal: the association is absent in Chile, where risk is more strongly associated with the age of H. pylori acquisition and socio-economic determinants. The dramatic global and regional variations in gastric cancer incidence and mortality rates offer the opportunity for scientific discovery and focused prevention programs.

Carcinoma of the stomach: A review of epidemiology, pathogenesis, molecular genetics and chemoprevention

Carcinoma of the stomach is still the second most common cause of cancer death worldwide, although the incidence and mortality have fallen dramatically over the last 50 years in many regions. The incidence of gastric cancer varies in different parts of the world and among various ethnic groups. Despite advances in diagnosis and treatment, the 5-year survival rate of stomach cancer is only 20 per cent. Stomach cancer can be classified into intestinal and diffuse types based on epidemiological and clinicopathological features. The etiology of gastric cancer is multifactorial and includes both dietary and nondietary factors. The major diet-related risk factors implicated in stomach cancer development include high content of nitrates and high salt intake. Accumulating evidence has implicated the role of Helicobacter pylori (H. pylori) infection in the pathogenesis of gastric cancer. The development of gastric cancer is a complex, multistep process involving multiple genetic and epigenetic alterations of oncogenes, tumor suppressor genes, DNA repair genes, cell cycle regulators, and signaling molecules. A plausible program for gastric cancer prevention involves intake of a balanced diet containing fruits and vegetables, improved sanitation and hygiene, screening and treatment of H. pylori infection, and follow-up of precancerous lesions. The fact that diet plays an important role in the etiology of gastric cancer offers scope for nutritional chemoprevention. Animal models have been extensively used to analyze the stepwise evolution of gastric carcinogenesis and to test dietary chemopreventive agents. Development of multitargeted preventive and therapeutic strategies for gastric cancer is a major challenge for the future.

Evaluation of nutrient intake and diet quality of gastric cancer patients in Korea

This study was conducted to identify dietary factors that may affect the occurrence of gastric cancer in Koreans. Preoperative daily nutrition intake and diet quality of patients diagnosed with gastric cancer were evaluated. Collected data were comparatively analyzed by gender. The results were then used to prepare basic materials to aid in the creation of a desirable postoperative nutrition management program. The subjects of this study were 812 patients (562 men and 250 women) who were diagnosed with gastric cancer and admitted for surgery at Soonchunhyang University Hospital between January 2003 and December 2010. Nutrition intake and diet quality were evaluated by the 24-hr recall method, the nutrient adequacy ratio, mean adequacy ratio (MAR), nutrient density (ND), index of nutritional quality (INQ), dietary variety score (DVS), and dietary diversity score (DDS). The rate of skipping meals and eating fast, alcohol consumption, and smoking were significantly higher in males than those in females. The levels of energy, protein, fat, carbohydrate, phosphorous, sodium, potassium, vitamin B₁, vitamin B₂, niacin, and cholesterol consumption were significantly higher in males than those in females. Intake of fiber, zinc, vitamin A, retinol, carotene, folic acid were significantly higher in females than those in males. MAR in males was significantly higher (0.83) than that in females (0.79). INQ values were higher in females for zinc, vitamin A, vitamin B₂, vitamin B₆, and folic acid than those in males. The average DVS was 17.63 for females and 13.19 for males. The average DDS was 3.68 and the male's average score was 3.44, whereas the female's average score was 3.92. In conclusion, males had more dietary habit problems and poor nutritional balance than those of females. Our findings suggest that proper nutritional management and adequate dietary education for the primary prevention of gastric cancer should be emphasized in men.

Inhibition of Grb2-mediated activation of MAPK signal transduction suppresses NOR1/CB1954-induced cytotoxicity in the HepG2 cell line

The nitroreductase oxidored-nitro domain containing protein 1 (NOR₁) gene may be involved in the chemical carcinogenesis of hepatic cancer and nasopharyngeal carcinoma (NPC). We have previously demonstrated that NOR₁ overexpression is capable of converting the monofunctional alkylating agent 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB1954) into a toxic form by reducing the 4-nitro group of CB1954. Toxic CB1954 is able to enhance cell killing in the NPC cell line CNE₁; however, the underlying mechanisms remain unknown. Using cDNA microarrays and quantitative real-time PCR, we previously discovered that NOR₁ increases the expression of growth factor receptor-bound protein 2 (Grb2) mRNA by 4.8-fold in the human hepatocellular carcinoma cell line HepG2. In the present study, we revealed that NOR₁ increased Grb2 protein expression by 3-fold in HepG2 cells. Additionally, we demonstrated that NOR₁ enhanced CB1954-induced cell killing in HepG2 cells, and cell cytotoxicity was inhibited with the tyrosine kinase inhibitor genistein, or by stable transfection of Grb2 small hairpin RNA (shRNA) pU6⁺²⁷-shGrb2 to silence the expression of Grb2. Western blot analysis revealed that Grb2 downregulation may reduce the activity of the mitogen-activated protein kinase (MAPK). Inhibiting the activation of MAPK using the methyl ethyl ketone (MEK) inhibtor PD98059 suppressed CB1954-induced cell killing. These results suggested that the NOR₁ gene enhances CB1954-mediated cell cytotoxicity through the upregulation of Grb2 expression and the activation of MAPK signal transduction in the HepG2 cell line.

Is neurodegenerative disease a long-latency response to early-life genotoxin exposure?

Western Pacific amyotrophic lateral sclerosis and parkinsonism-dementia complex, a disappearing neurodegenerative disease linked to use of the neurotoxic cycad plant for food and/or medicine, is intensively studied because the neuropathology (tauopathy) is similar to that of Alzheimer's disease. Cycads contain neurotoxic and genotoxic principles, notably cycasin and methylazoxymethanol, the latter sharing chemical relations with nitrosamines, which are derived from nitrates and nitrites in preserved meats and fertilizers, and also used in the rubber and leather industries. This review includes new data that influence understanding of the neurobiological actions of cycad and related genotoxins and the putative mechanisms by which they might trigger neurodegenerative disease.

The role of interleukin DNA polymorphisms in gastric cancer

Gastric carcinoma is one of the most widespread malignancies worldwide. Interleukins are the key group of cytokines which may have tumor-promoting or tumor-suppressing effect, and receptors for them, of course, have the same importance in this context. However, mechanisms of their impact on tumor are not fully understood up to date. Numerous studies provide conflicting data, that makes picture more confusing and complicated. It is known that single nucleotide polymorphisms in interleukin genes may dramatically affect on protein expression level, or alter its functions, which may lead to gastritis or ulcer, and eventually promote cancer occurrence. Furthermore, some of these genetic polymorphisms may serve as predictive factors for cancer prognosis and prevention. In order to understand the impact of each genetic polymorphism, the review of IL-1B, IL-4, IL-6, IL-8, IL-10, IL17A, IL-17F DNA polymorphisms on gastric carcinoma was done, and risk alleles were recommended for further research.

Gastric carcinogenesis

INTRODUCTION

In most patients, gastric cancer is diagnosed in advanced stage. Curative treatment options are limited and the mortality is high. The process of gastric carcinogenesis is triggered by Helicobacter pylori-driven gastritis and is further characterized by its complexity of interaction with other risk factors. Health care systems are challenged for the improvement of prevention, early diagnosis, and effective treatments.

METHODS

An extensive literature research has been performed to elucidate the interplay between etiological factors involved in gastric carcinogenesis.

RESULTS

H. pylori is the most important carcinogen for gastric adenocarcinoma. Evidence is provided by experiments including animal studies as well as clinical observational and interventional studies in humans. Eradication has the potential to prevent gastric cancer and offers the greatest benefit if performed before premalignant changes of the gastric mucosa have occurred. Bacterial virulence factors are essential players in modulating the immune response involved in the initiation of the carcinogenesis in the stomach. Host genetic factors contribute to the regulation of the inflammatory response and in the aggravation of mucosal damage. The harmful role of environmental factors is restricted to salt intake and smoking of tobacco. The ingestion of fruit and vegetables has some protective effect.

CONCLUSION

Infection with H. pylori is the major risk factor for gastric cancer development, and thus, eradication of the Helicobacter offers a promising best option for prevention of the disease. Bacterial virulence, host genetic factors, and environmental influences are interacting in the multifactorial process of gastric carcinogenesis.

Vascular endothelial growth factor +936C/T polymorphism and gastric cancer risk: A meta-analysis

The aim of this study was to determine whether the vascular endothelial growth factor (VEGF) +936C/T polymorphism confers susceptibility to gastric cancer (GC) by conducting a meta-analysis. Publications addressing the association between the VEGF +936C/T polymorphism and GC risk were selected from the Pubmed, Embase and CBM databases. Data were extracted from the studies by two independent reviewers. The meta-analysis was performed using RevMan 5.0.25 and STATA 9.2 software. From these data, the odds ratio (OR) with 95% confidence interval (CI) was calculated. Finally, 8 case-control studies were retrieved reporting a total of 2,131 gastrointestinal cancer patients and 2,670 controls. Meta-analysis results showed that there was no significant association between the VEGF +936C/T polymorphism and GC risk in all comparisons of the T allele vs. C allele (OR=1.08, 95% CI 0.90-1.30, P=0.42), CT+TT vs. CC (OR=1.08, 95% CI 0.87-1.34, P=0.49), TT vs. CC+CT (OR=1.14, 95% CI 0.85-1.53, P=0.37), TT vs. CC (OR=1.18, 95% CI 0.87-1.59, P=0.28) and TT vs. CT (OR=1.11, 95% CI 0.79-1.56, P=0.56). This meta-analysis confirms that there is a lack of association between the VEGF +936C/T polymorphism and GC risk.

The Role of Polyphenols, β-Carotene, and Lycopene in the Antioxidative Action of the Extracts of Dried, Edible Mushrooms

One of the nutritional benefits of mushrooms is the presence of bioactive secondary metabolites which have been reported to exert various beneficial effects in vivo. Therefore, we selected thirteen frequently consumed species of Polish mushrooms and determined the concentration of polyphenols, flavonoids, β-carotene, and lycopene in aqueous and methanolic extracts of dried fruiting bodies as well as their reducing power and ability to scavenge ABTS cation radical. We found that the concentration of antioxidants is different in different species and in various parts of the fruiting body of mushrooms. We observed a strong correlation (r > 0.9) between the concentration of total phenolics and reducing power/scavenging effects in both aqueous and methanolic extracts, while this correlation was moderate for flavonoids. Beta-carotene did not contribute discernibly to the antioxidative properties of the extracts, while lycopene had a significant contribution to the scavenging activity of methanolic mushroom extracts.

Fruit and vegetable consumption and risk of distal gastric cancer in the Shanghai Women's and Men's Health studies

Results from case-control and cohort studies of the association between fruit and vegetable consumption and gastric cancer risk have been inconsistent. Cases for the current study consisted of incident distal gastric cancers identified between 1996 and 2007 among members of the Shanghai Women's Health Study (n = 206) and the Shanghai Men's Health Study (n = 132). Intakes of fruits, vegetables, and select micronutrients were assessed on the basis of validated food frequency questionnaires. Multivariate-adjusted hazards ratios and 95% confidence intervals were calculated by Cox proportional hazards regression. For women, no associations were found between gastric cancer risk and the highest intake of fruits (hazard ratio (HR) = 1.02, 95% confidence interval (CI): 0.68, 1.54; P(trend) = 0.87) or vegetables (HR = 0.89, 95% CI: 0.60, 1.31; P(trend) = 0.32). For men, increased fruit intake was associated with decreased risk of distal gastric cancer (for the highest quartile of intake, HR = 0.50, 95% CI: 0.29, 0.84; P(trend) = 0.004), but no association was seen with increased intake of vegetables (HR = 1.00, 95% CI: 0.59, 1.68; P(trend) = 0.87). The inverse association with fruit intake for men was more evident among ever smokers (P(trend) = 0.001) than never smokers (P(trend) = 0.67). No associations between dietary intakes of select antioxidant micronutrients were seen for men or women. Fruit intake is inversely associated with distal gastric cancer risk among men in Shanghai, China.

Inhibition of cancer cell replication by inorganic nitrite

Nitrite has been implicated in carcinogenesis, especially under acidic conditions such as in the stomach or in urine, where it forms nitrosating species that can react with secondary amines to form nitrosamines. Recent studies have shown that nitrite and acid form a variety of other nitrogen oxides in vivo including nitric oxide-a compound with documented antitumor activity. Here we tested the effects of nitrite on bladder tumor cells incubated in mildly acidified urine. Nitrite (50 microM) inhibited thymidine incorporation in human T24 bladder cancer cells. This inhibition required slight acidification (pH 5.5-6), and no effect of nitrite could be observed at pH 7. Nitrite effects were further augmented in the presence of ascorbic acid, whereas ascorbic acid alone had no effect. The effects were paralleled by formation of nitric oxide gas. We here demonstrate an inhibitory effect of nitrite on cancer cell replication at concentrations and acidity commonly found in urine and gastric juice. The inhibitory effect is likely caused by nitric oxide and possibly other reactive nitrogen oxides formed from acidified nitrite.

Alcohol and tobacco use in relation to gastric cancer: a prospective study of men in Shanghai, China

BACKGROUND

Epidemiologic findings of tobacco and alcohol use in relation to gastric cancer are inconsistent. Well-designed prospective studies examining their relationship are sparse.

METHODS

The association between cigarette smoking/alcohol intake and gastric cancer risk was examined in a population-based prospective cohort of 18,244 middle-aged and older men in Shanghai, China, who were enrolled in the study during 1986-1989. After up to 20 years of follow-up, 391 incident gastric cancer cases were identified. Cox proportional hazards regression models were used to estimate hazard ratios (HR) and corresponding 95% confidence intervals (95% CI).

RESULTS

Ever smokers experienced a statistically significant increased risk of gastric cancer (HR, 1.59; 95% CI, 1.27-1.99) compared with nonsmokers after adjustment for alcohol intake and other confounders. Among nondrinkers, smokers experienced 80% increased risk of gastric cancer (HR, 1.81; 95% CI,1.36, 2.41). Conversely, heavy drinkers experienced a statistically significant increase in risk of gastric cancer (HR, 1.46; 95% CI, 1.05-2.04) among all subjects and a statistically nonsignificant 80% increased risk among never smokers. Further adjustment for Helicobacter pylori serology, serum levels of beta-carotene and vitamin C, and urinary level of total isothiocyanates in combination with glutathione S-transferase (GST) M1 and GSTT1 genotypes did not materially change the associations between smoking/alcohol consumption and gastric cancer risk.

CONCLUSIONS

These results suggest that cigarette smoking and alcohol consumption may exert independent effects on the development of gastric cancer in this high-risk population.

IMPACT

Modification of these lifestyle choices may reduce the incidence of gastric cancer.

Camel cocktail sausage and its physicochemical and sensory quality

The objective of this study was to compare the nutritional values of camel semitendinosus muscles with those of calves. Then, sausages were made from camel meat, beef and equal proportions of each and stored at 4 degrees C for 45 days. The composition, physicochemical characteristics, sensory properties, and microstructure of the samples were evaluated. The proximate composition of meat from the two species was significantly different. Beef contained a significantly higher amount of vitamin E, whereas camel meat had better profile of fatty acid and higher iron content. Camel meat had a higher pH but similar myofibrillar protein content as beef. Sausages made from 100% camel meat also had higher pH and cooking yield along with higher a* (redness) and lower L* (lightness) than the others. 2-Thiobarbitoric acid values among these treatments were significantly different. Samples containing 50% of each meat had a higher resistance to shear force; however, panelists could not detect any significant difference in tenderness of the samples.

Association between PARP-1 polymorphisms and susceptibility to gastric cancer

AIM: To investigate the association between the Val762Ala and Lys940Arg polymorphisms of the poly(ADP-ribose) polymerase-1 (PARP-1) gene and susceptibility to gastric cancer in a Chinese Han population in He'xi area of Gansu Province.

METHODS: All investigated subjects were divided into two groups: 150 gastric cancer patients and 152 controls. The SNaPshot single nucleotide polymorphism (SNP) genotyping method was used to analyze the genotypes of PARP-1 Val762Ala and Lys940Arg. Helicobacter pylori (H.pylori) IgG antibody was detected by enzyme-linked immunosorbent assay (ELISA). The results were analyzed using the SPSS16.0 software package.

RESULTS: PARP-1 940 Lys/Arg and 762 Val/Ala genotypes were overrepresented in gastric cancer patients compared with controls (OR = 2.917 and 1.685; 95%CI: 1.430-5.947 and 1.040-2.729; P = 0.002 and 0.034, respectively). In smoking subjects, the risk of gastric cancer in PARP-1 940 Lys/Arg genotype carriers was 8.430-fold higher than that in Lys/Lys carriers (OR = 8.340, 95%CI: 2.664-26.144, P = 0.000). In drinking subjects, PARP-1 940 Lys/Arg genotype carriers had a 3.333-fold higher risk of gastric cancer than Lys/Lys carriers (OR = 3.333, 95%CI: 1.214-9.155, P = 0.015). In H.pylori IgG-positive subjects, PARP-1 762 Ala/Ala genotype carriers had a 2.360-fold increased risk of gastric cancer than Val/Val carriers (OR = 2.360, 95%CI: 1.256-4.433, P = 0.007). The subjects carrying PARP-1 940 Lys/Arg and PARP-1 Ala/Ala or Val/Ala genotypes had a 4.2-fold increased risk of gastric cancer compared with those carrying PARP-1 940 Lys/Lys and PARP-1 762Val/Val genotypes (OR = 4.200, 95%CI: 1.430-12.338, P = 0.006).

CONCLUSION: PARP-1 940Lys/Arg and PARP-1 762Ala/Ala or Ala/Ala genotypes are associated with a higher risk of gastric cancer. There are multiplicative joint effects between PARP-1 940 Lys/Arg genotype and smoking or drinking, between PARP-1 762 Val/Ala or Ala/Ala genotypes and H.pylori infection, and between PARP-1 Lys940Arg and PARP-1 Val762Ala genotypes in increasing the risk of gastric cancer.

Selenium status and the risk of esophageal and gastric cancer subtypes: the Netherlands cohort study

BACKGROUND & AIMS

Selenium may protect against the development of esophageal squamous cell carcinoma (ESCC), esophageal adenocarcinoma (EAC), and gastric cardia adenocarcinoma (GCA). Only in very few studies have the associations with ESCC and GCA been investigated, and no epidemiologic studies exist on EAC.

METHODS

We studied the association between selenium and risk of ESCC, EAC, and GCA within the prospective Netherlands Cohort Study, conducted among 120,852 men and women aged 55-69 years at baseline. In September 1986, the cohort members completed a questionnaire on risk factors for cancer and provided toenail clippings for determination of baseline selenium status. After 16.3 years of follow-up, 64 ESCC, 112 EAC, and 114 GCA cases and 2072 subcohort members were available for case-cohort analysis. Incidence rate ratios (RR) were calculated using Cox proportional hazards models.

RESULTS

In multivariable analyses of selenium status, we found an inverse association with ESCC (RR(per standard unit increment), 0.80; 95% confidence interval [CI]: 0.67-0.96) and a borderline significant inverse association with GCA (RR, 0.91; 95% CI: 0.80-1.02). No overall association was observed for EAC (RR, 1.05; 95% CI: 0.95-1.15), but, for women and never smokers, significant inverse associations were found (RR(per standard unit increment), 0.72; 95% CI: 0.61-0.84 and RR(per standard unit increment), 0.74; 95% CI: 0.64-0.86, respectively).

CONCLUSIONS

This prospective study supports an inverse association between toenail selenium and risk of ESCC and GCA and suggests an inverse association with risk of EAC in subgroups (women, never smokers, and low antioxidant consumers). These associations need confirmation.

Fresh and pickled vegetable consumption and gastric cancer in Japanese and Korean populations: a meta-analysis of observational studies

It is widely known that vegetable consumption contributes to reducing the risk of gastric cancer (GC). However, the incidence rates of GC remain high in both Japanese and Korean populations, even though they have a high consumption of total vegetables. This may be due to the fact that Japanese and Koreans mainly consume processed vegetables, such as cooked, salted, or pickled vegetables, rather than fresh vegetables. To determine whether the intakes of fresh and pickled vegetables have different effects on the risk of GC in Japanese and Korean populations, we carried out a meta-analysis of published epidemiological reports. Eight studies on the consumption of fresh vegetables and 14 studies on the consumption of pickled vegetables related to GC risk were included in this meta-analysis. Four studies exploring differences in GC risk in men and women were considered separately. We observed that a high intake of fresh vegetables was significantly associated with a decreased risk of GC (overall summary OR = 0.62, 95% CI = 0.46-0.85) but that a high intake of pickled vegetables was significantly associated with an increased risk of GC (overall summary OR = 1.28, 95% CI = 1.06-1.53). The results of this meta-analysis provide evidence that a high intake of pickled vegetables may increase GC risk and suggest that a high consumption of fresh vegetables, rather than a large total amount of vegetables including pickled vegetables, is important to reduce GC risk.

Hereditary diffuse gastric cancer

Gastric cancer is one of the world's leading causes of cancer mortality. A small percentage of cases can be attributed to heritable mutations in highly penetrant cancer susceptibility genes. In this chapter we will focus on the genetic cause of hereditary diffuse gastric cancer (HDGC). Until 10 years ago, individuals from these families lived with the uncertainty of developing lethal gastric cancer. Today, HDGC families can be identified, tested for causative mutations in CDH1, and for those families where a pathogenic mutation can be identified, prophylactic total gastrectomy can be implemented in asymptomatic mutation carriers who elect to virtually eliminate their risk of developing this lethal disease.

Isothiocyanates, glutathione S-transferase M1 and T1 polymorphisms and gastric cancer risk: a prospective study of men in Shanghai, China

Isothiocyanates (ITC) in cruciferous vegetables may be chemopreventive against gastric cancer development. Glutathione S-transferases (GSTs) may modify the chemopreventive effect of ITC. The relationship between urinary total ITC and risk of gastric cancer was prospectively examined. Between 1986 and 1989, 18,244 middle-aged men in Shanghai, China were enrolled in a prospective study of diet and cancer and donated baseline urine and blood samples. Urinary ITC was quantified for 307 incident cases of gastric cancer that occurred during the first 16 years of follow-up, and 911 matched control subjects. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression methods. Seropositivity for antibodies to Helicobacter pylori and homozygous deletions of GSTM1 and GSTT1 were determined. Compared to the first tertile, ORs (95% CIs) of gastric cancer for the second and third tertiles of urinary total ITC were 0.83 (0.61-1.15) and 0.66 (0.47-0.94) (p(trend) = 0.02). A stronger protective effect of ITC against gastric cancer development was seen among men with homozygous deletion of GSTM1 (third tertile versus first tertile, OR = 0.50, 95% CI = 0.27-0.93) or GSTT1 (third tertile vs. first tertile, OR = 0.47, 95% CI = 0.25-0.88), and particularly with deletions of both GSTM1 and GSTT1 (second and third tertiles vs. first tertile, OR = 0.44, 95% CI = 0.21-0.93). In this cohort of Chinese men at high risk for gastric cancer, isothiocyanates may protect against the development of gastric cancer. The protection may be stronger for individuals genetically deficient in enzymes that metabolize these chemopreventive compounds.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Genetic variation in sodium-dependent ascorbic acid transporters and risk of gastric cancer in Poland

Higher ascorbic acid consumption is associated with a reduced risk of gastric cancer in numerous epidemiologic studies. We investigated whether single nucleotide polymorphisms (SNPs) in SLC23A1 and SLC23A2--genes that encode key ascorbic acid transport proteins--affect gastric cancer risk in 279 incident cases and 414 age- and gender-matched controls drawn from a population-based case-control study in Poland. Compared to subjects who were homozygous for the common G allele of the SLC23A2 SNP rs12479919, carriers of the AA genotype had a 41% lower risk of gastric cancer [odds ratio (OR)=0.59, 95% confidence interval (CI): 0.36-0.95; P trend=0.06]. A haplotype that contained the common allele of the rs6139591, rs2681116 and rs14147458 SNPs in SLC23A2 was also significantly inversely associated with gastric malignancy. No other polymorphisms in either gene were related to risk, and there was no effect modification by ascorbic acid intake. These findings suggest that genetic variation in SLC23A2 impacts gastric cancer risk, although confirmation in other studies is required.

Case-crossover and case-time-control designs in birth defects epidemiology

The case-crossover and the case-time-control designs can be used to evaluate the effect of intermittent exposures on the risk of acute events. To explore how birth defects epidemiology could benefit from these approaches, the authors compared them with a traditional case-control study design that evaluated the association between use of folic acid antagonists during the second and third pregnancy months and the risk of cardiovascular defects. Among 3,870 cases and 8,387 control infants in the Slone Epidemiology Center Birth Defects Study (1976-1998), the odds ratio was 2.3 (95% confidence interval (CI): 1.4, 3.9). The case-crossover approach compared folic acid antagonist use between the 2-month embryologically sensitive period (case window) and the 2 months preceding the last menstrual period (control window) among mothers of case infants (odds ratio = 1.0, 95% CI: 0.5, 2.0). Although it controls between-person confounding and avoids issues of control selection, this design may be biased by time trends of exposure prevalence during pregnancy. The case-time-control design, which adjusts for exposure time trends under certain assumptions, yielded an odds ratio of 2.9 (95% CI: 1.2, 7.2), but it requires controls. In the presence of gestational time trends of exposure, the new designs do not offer clear advantages over the case-control design.