Population-based prospective study of the combined influence of cigarette smoking and Helicobacter pylori infection on gastric cancer incidence: the Hisayama Study

Antacids and reflux esophagitis as a risk factor for gastric neoplasm of fundic-gland type: A retrospective, matched case-control study

BACKGROUND AND AIM

Since the first report of gastric adenocarcinoma of the fundic-gland type in 2010, the clinicopathological characteristics of gastric neoplasm of the fundic-gland type (GNFG) have become clearer; however, their risk factors remain unclear. This exploratory study aimed to identify the risk factors for GNFG.

METHODS

We conducted a single-center, retrospective, matched case-control study using medical information recorded at our health management center from January 2014 to July 2023. During this period, 39 240 people underwent upper gastrointestinal endoscopy. GNFG were extracted as cases and matched to controls, according to age and sex, in a 1:8 ratio, excluding those with a history of gastrointestinal surgery and those with a history or comorbidity of cancer. Univariate analysis was used to compare patient background and endoscopic findings. Multivariable analysis was performed, adjusting for factors with P values < 0.1 and antacid use.

RESULTS

A total of 20 GNFG cases and 160 matched healthy controls were included. In the univariate analysis, only reflux esophagitis was significantly more common in GNFG (40.0% vs 18.1%; P = 0.036). Factors antacids and duodenitis had P values < 0.1. Logistic regression analysis was performed, adjusting for antacids, reflux esophagitis, and duodenitis. Antacids and reflux esophagitis were the independent risk factors for GNFG (odds ratio = 3.68 [95% confidence interval: 1.04-11.91] and 3.25 [95% confidence interval: 1.11-9.35]).

CONCLUSIONS

Although the sample of patients with GNFG was small, antacids and reflux esophagitis were identified as a risk factor. The pathogenesis of antacids and reflux esophagitis may be involved in the development of GNFG.

Multicenter study of invasive gastric cancer detected after 10 years of Helicobacter pylori eradication in Japan: Clinical, endoscopic, and histopathologic characteristics

Objectives

Gastric cancer can be diagnosed even in patients long after Helicobacter pylori eradication. Most cases involve intramucosal lesions; however, some are invasive and require surgery. To clarify appropriate long-term surveillance methods, this study compared invasive gastric cancer diagnosed ≥10 and <10 years after eradication.

Methods

This retrospective multicenter study included 14 institutions. We included 377 patients with gastric cancer with submucosal or deep invasion after surgical or endoscopic resection. Ordered logistic regression analysis was used to explore the factors contributing to the pathological stage and histological type.

Results

Invasive gastric cancer was detected in 84 patients (Group L) and 293 patients (Group S) ≥10 and <10 years after H. pylori eradication, respectively. Endoscopic mucosal atrophy at the time of cancer detection was similar in both groups; 50% of the patients had severe atrophy. Annual endoscopy correlated with early pathological stage (odds ratio [OR] 0.28, 95% confidence interval [CI] 0.14-0.54, p < 0.001). Group L exhibited an independent correlation with the advanced pathological stage (OR 2.27, 95% CI 1.06-4.88, p = 0.035) and the undifferentiated type (OR 2.12, 95% CI 1.16-3.90, p = 0.015). The pure differentiated type and early pathological stage significantly (p = 0.001) correlated with severe mucosal atrophy in Group S but not in Group L.

Conclusions

Invasive cancers diagnosed ≥10 years after H. pylori eradication were likely to be more malignant in histological type and pathological stage. Gastric cancer surveillance should continue regardless of endoscopic atrophy, particularly ≥10 years after eradication.

Trends in the prevalence of atrophic gastritis and Helicobacter pylori infection over a 10‑year period in Japan: The ROAD study 2005‑2015

Few large population-based studies have examined the prevalence of atrophic gastritis (AG) and Helicobacter pylori infection in Japan. The purpose of the present study was to estimate the prevalence of AG and H. pylori infection by age, in addition to investigating their change rates from 2005 to 2016 in Japan using data from a large population-based cohort. A total of 3,596 participants [1,690 in the baseline survey (2005-2006) and 1,906 at the fourth survey (2015-2016)] aged 18 to 97 years were included in the cohort. The prevalence of AG and H. pylori infection were examined at baseline and in the fourth survey based on serological tests for the H. pylori antibody titer and pepsinogen levels. The prevalence of AG and H. pylori infection were 40.1% (men, 44.1%; women, 38.0%) and 52.2% (men, 54.8%; women, 50.8%), respectively, at baseline. AG seropositivity rates showed a significant decrease from 40.1 to 25.8% in 10 years. H. pylori seropositivity rates decreased significantly from 52.2 to 35.5% in 10 years. Stratified for age, the prevalence of AG showed an increasing trend with age, whereas the prevalence of H. pylori infection increased with aging, except for in the elderly group, showing an inverted U-shaped association. In this population-based, cross-sectional study with a 10-year interval survey, the prevalence of AG and H. pylori infection decreased significantly. This change may influence the prevalence of H. pylori-related diseases, including extra-gastric disorders associated with H. pylori-induced systemic subclinical inflammation and hypochlorhydria, such as colorectal neoplasia and arteriosclerosis.

Association between Body Mass Index and Risk of Gastric Cancer by Anatomic and Histologic Subtypes in Over 500,000 East and Southeast Asian Cohort Participants

BACKGROUND

This study was performed to investigate the association between body mass index (BMI) and gastric cancer in East and Southeast Asia where most of gastric cancer is non-cardia gastric cancer.

METHODS

On the basis of 8,997 gastric cancer cases among the Asia Cohort Consortium participants from China, Japan, Korea, and Singapore (N = 538,835), we assessed gastric cancer risk according to BMI by calculating hazard ratios (HR) and 95% confidence intervals (CI) using the Cox proportional hazard regression model.

RESULTS

A U-shaped associations between BMI and gastric cancer risk were observed. Gastric cancer risks in underweight group (&lt;18.5 kg/m2) and in obesity group (≥27.5 kg/m2) were higher than reference BMI group (23-24.9 kg/m2; HR, 1.15; 95% CI, 1.05-1.25 for underweight; HR, 1.12; 95% CI, 1.03-1.22 for obesity, respectively). The associations of underweight and obesity with gastric cancer risk were consistent in the analyses for non-cardia gastric cancer, intestinal-type gastric cancer, and late-onset gastric cancer. No significant association of underweight and obesity with the risk of cardia gastric cancer, diffuse-type gastric cancer, and early-onset gastric cancer was observed. In addition, we found that the U-shaped association between BMI and gastric cancer risk remained in nonsmokers, while only underweight was related to increased gastric cancer risk in smokers.

CONCLUSIONS

BMI has a U-shaped association with gastric cancer risk in East and Southeast Asian population, especially for the non-cardia gastric cancer, intestinal-type gastric cancer, and late-onset gastric cancer.

IMPACT

Future studies with consideration of anatomic location and histology of gastric cancer are needed to establish the association of underweight as well as obesity with gastric cancer risk.

Invited Commentary: The Use of Population Attributable Fractions in Studies of Vaccine Hesitancy

Vaccine hesitancy-the delay or refusal of vaccines despite their availability-has been linked to lower vaccination rates and outbreaks of vaccine-preventable diseases. Using cross-sectional surveys of 78,725 parents and other family members in the United States, Nguyen et al. (Am J Epidemiol. 2022;191(9):1626-1635) calculated the population attributable fraction (PAF) of vaccine hesitancy on nonreceipt of recommended childhood vaccines, including influenza vaccine. The PAF is readily calculated: p(rr - 1)/rr, where p is the proportion of those hesitant among nonvaccinated individuals, and rr is the risk ratio of nonvaccination between those hesitant over those nonhesitant. By vaccine, the PAF ranged from 6.5% for nonreceipt of the hepatitis B vaccine birth dose to 31.3% for nonreceipt of the diphtheria-tetanus-pertussis vaccine dose 3. For nonreceipt of influenza vaccine, the PAF varied geographically, with relatively high values in some Northeast (e.g., New York at 22.6%) and Northwest (e.g., Oregon at 23.0%) states and lower values in certain Southern (e.g., Louisiana at 7.5%) and Mountain West (e.g., Utah at 8.8%) states. The PAF can elucidate the contribution of vaccine hesitancy on nonvaccination in different circumstances. Future studies can apply this technique in different populations and incorporate different measures of vaccine hesitancy.

A prospective cohort study on the association between waterpipe tobacco smoking and gastric cancer mortality in Northern Vietnam

Tobacco consumption, as a worldwide problem, is a risk factor for several types of cancer. In Vietnam, tobacco consumption in the form of waterpipe tobacco smoking is common. This prospective cohort study aimed to study the association between waterpipe tobacco smoking and gastric cancer mortality in Northern Vietnam. A total of 25,619 eligible participants were followed up between 2008 and 2019. Waterpipe tobacco and cigarette smoking data were collected; semi-quantitative food frequency and lifestyle questionnaires were also utilized. Gastric cancer mortality was determined via medical records available at the state health facilities. A Cox proportional hazards model was used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI). During 314,992.8 person-years of follow-up, 55 men and 25 women deaths due to gastric cancer were identified. With never-smokers as the reference, the risk of gastric cancer mortality was significantly increased in participants who were ever-smoking (HR = 2.43, 95% CI = 1.35–4.36). The positive risk was also observed in men but was not significantly increased in women. By types of tobacco use, exclusive waterpipe smokers showed a significantly increased risk of gastric cancer mortality (HR = 3.22, 95% CI = 1.67–6.21) but that was not significantly increased in exclusive cigarette smokers (HR = 1.90, 95% CI = 0.88–4.07). There was a significant positive association between tobacco smoking and gastric cancer death for indicators of longer smoking duration, higher frequency per day, and cumulative frequency of both waterpipe and cigarette smoking. Waterpipe tobacco smoking would significantly increase the risk of gastric cancer mortality in the Vietnamese population. Further studies are required to understand the waterpipe tobacco smoking-driven gastric cancer burden and promote necessary interventions.

Chlamydia pneumoniae and Helicobacter pylori infections and immunological profile of community-dwelling older adults

Chronic bacterial infections are associated with changes in the immunosenescence process and immunological biomarkers can assist in monitoring these changes. The identification of this immunological profile is important because Chlamydia pneumoniae (C. pneumoniae) and Helicobacter pylori (H. pylori) infections are important factors of morbidity and mortality among the older adults. This study aimed to identify changes in the immunological profile in the presence of C. pneumoniae and H. pylori infections among community-dwelling older adults. This is a cross-sectional study that used data from 1432 participants from the Bambuí Cohort Study of Aging, Minas Gerais, Brazil. The presence of immunoglobulin G (IgG) for C. pneumoniae and H. pylori was considered a dependent variable and assessed in the participants' serum using the enzyme-linked immunosorbent assay (ELISA). In assessing the immunological profile, the following inflammatory markers were considered: CXCL8, CXCL9, CXCL10, CCL2, CCL5, IL-1β, IL-6, IL-10, IL-12, TNF, and CRP. Associations were assessed by logistic regression, estimating odds ratios and confidence intervals (95%) using the Stata® V.13.1 software. The seroprevalence of anti-C. pneumoniae and anti-H. pylori antibodies was 55.9% and 70.3%, respectively. While high levels of anti-C. pneumoniae antibodies were associated with higher concentrations of CXCL10 and IL-10, higher levels of IL-1β and IL-6 were inversely associated with the titration of anti-H. pylori antibodies. The results characterize immunological profiles associated with these chronic infections and reinforce the potential effects of biomarkers on infections by these bacteria and on the immunosenescence process.

Overview on the Role of E-Cadherin in Gastric Cancer: Dysregulation and Clinical Implications

Gastric cancer is the fifth most common cancer and the third most common cause of cancer death all over the world. E-cadherin encoded by human CDH1 gene plays important roles in tumorigenesis as well as in tumor progression, invasion and metastasis. Full-length E-cadhrin tethered on the cell membrane mainly mediates adherens junctions between cells and is involved in maintaining the normal structure of epithelial tissues. After proteolysis, the extracellular fragment of the full-length E-cadhein is released into the extracellular environment and the blood, which is called soluble E-cadherin (sE-cadherin). sE-cadherin promots invasion and metastasis as a paracrine/autocrine signaling molecule in the progression of various types of cancer including gastric cancer. This review mainly summarizes the dysregulation of E-cadherin and the regulatory roles in the progression, invasion, metastasis, and drug-resistance, as well as its clinical applications in diagnosis, prognosis, and therapeutics of gastric cancer.

Population Attributable Fraction of Helicobacter pylori Infection-Related Gastric Cancer in Korea: A Meta-Analysis

PURPOSE

This study aimed to determine the proportion of gastric cancer attributable to Helicobactor pylori in the Korean population. Infection with H. pylori has been recognized as the most significant risk factor for gastric cancer. In Korea, gastric cancer is the most common cancer that accounted for 13.3% of all cancers in 2016. In particular, men are most commonly diagnosed with gastric cancer; the age-standardized incidence rate in men is 49.6 per 100,000, which is more than twice the incidence in women.

MATERIALS AND METHODS

The population attributable fraction (PAF) was calculated as a function of the relative risk (RR) of gastric cancer associated with H. pylori infections. To estimate PAF of gastric cancer due to H. pylori, the prevalence of H. pylori infections was extrapolated for the year of 1990 and a pooled RR was obtained by conducting a meta-analysis of studies recently published in Korea.

RESULTS

The estimated prevalence of H. pylori was 76.4% in men and 71.9% in women. The RRs (95% confidence interval) pooled from case-control studies using a random effects model was 1.69 (1.29-2.22) for overall gastric cancer and 2.17 (1.04-4.55) for non-cardia gastric cancer. Using the RR for overall gastric cancer, the estimated PAFs due to H. pylori were 34.5% in men and 33.2% in women.

CONCLUSION

The occurrence of gastric cancer in Koreans may be affected by other risk factors in addition to H. pylori infection, which may contribute to increasing baseline risk for gastric cancer.

Trends and age-period-cohort analysis of upper aerodigestive tract and stomach cancer mortality in Lithuania, 1987-2016

OBJECTIVES

Lithuania has among the highest mortality rates for upper aerodigestive tract (UADT) and stomach cancer in Europe. The aim of this study was to analyze trends during the period 1987-2016 in Lithuania, evaluating the effect of birth-cohort, period, and age.

STUDY DESIGN

Observational time trends study.

METHODS

Data on numbers of deaths and population size by each calendar year in 5-year age groups in 1987-2016 were obtained from the WHO mortality database. Joinpoint regression analysis was used to evaluate changes in time trends. Age-period-cohort analysis was performed to assess age, calendar period of death, and birth-cohort effects.

RESULTS

UADT cancer mortality in men increased between 1987 and 1993, annual percentage change (APC) = 6.6% (95% confidence interval [CI]: 3.8, 9.4), and was stable thereafter, APC = 0.3% (95% CI: 0.0, 0.6). The age-standardized mortality rate (ASMR) was 23.6/100,000 in 2016. In women, rates increased steadily by 1.6% (95% CI: 0.9%, 2.3%) per year from 1987 to 2016, ASMR = 2.3/100,000 in 2016. Age-period-cohort analysis showed statistically significant cohort effects in both sexes. In men, rates peaked in birth-cohorts born around 1952, declined in 1957-1962 birth-cohorts, and fluctuated in later birth-cohorts. In women, rates started rising in 1947 birth cohort and peaked in the 1967 birth cohort. Stomach cancer mortality declined throughout the study period in men by -2.4%, (95% CI: -2.6%, -2.1%) annually, and women by -2.8% (95% CI: -3.1%, -2.4%), ASMR = 16.1/100,000 and 6.0/100,000 in 2016, respectively. Birth-cohort effects were significant in both sexes. Rates decreased in cohorts born around 1920 onwards, but declines in the youngest generations have slowed in men and reversed in women.

CONCLUSIONS

The birth-cohort effects in UADT and stomach cancer mortality trends imply that the elevated burden in Lithuania could be reduced by effective strategies targeting known risk factors. Further research in causes of unfavorable trends in younger cohorts is warranted.

Occupational Class and Risk of Cardiovascular Disease Incidence in Japan: Nationwide, Multicenter, Hospital-Based Case-Control Study

Background

In contemporary Western settings, higher occupational class is associated with lower risk for cardiovascular disease (CVD) incidence, including coronary heart disease (CHD) and stroke. However, in non‐Western settings (including Japan), the occupational class gradient for cardiovascular disease risk has not been characterized.

Methods and Results

Using a nationwide, multicenter hospital inpatient data set (1984–2016) in Japan, we conducted a matched hospital case‐control study with ≈1.1 million study subjects. Based on a standard national classification, we coded patients according to their longest‐held occupational class (blue‐collar, service, professional, manager) within each industrial sector (blue‐collar, service, white‐collar). Using blue‐collar workers in blue‐collar industries as the referent group, odds ratios and 95% CIs were estimated by conditional logistic regression with multiple imputation, matched for sex, age, admission date, and admitting hospital. Smoking and drinking were additionally controlled. Higher occupational class (professionals and managers) was associated with excess risk for CHD. Even after controlling for smoking and drinking, the excess odds across all industries remained significantly associated with CHD, being most pronounced among managers employed in service industries (odds ratio, 1.19; 95% CI, 1.08–1.31). On the other hand, the excess CHD risk in higher occupational class was offset by their lower risk for stroke (eg, odds ratio for professionals in blue‐collar industries, 0.77; 95% CI, 0.70–0.85).

Conclusions

The occupational “gradient” in cardiovascular disease (with lower risk observed in higher status occupations) may not be a universal phenomenon. In contemporary Japanese society, managers and professionals may experience higher risk for CHD.

Trends in the Incidence of Stomach Cancer in Golestan Province, a High-risk Area in Northern Iran, 2004-2016

BACKGROUND

We aimed to present the temporal and geographical trends in the incidence of stomach cancer in the Golestan province, a high-risk area in Northern Iran.

METHODS

This study was conducted on stomach cancer cases registered in the Golestan Population-based Cancer Registry (GPCR) during 2004-2016. Age-standardized incidence rates (ASRs) per 100000 person-years were calculated. The Joinpoint regression analysis was used to calculate the average annual percent changes (AAPC). We also calculated the contribution of population aging, population size and risk to the overall changes in incidence rates.

RESULTS

Overall, 2964 stomach cancer patients were registered. The ASR of stomach cancer was significantly higher in men (26.9) than women (12.2) (P<0.01). There was a significant decreasing trend in incidence of stomach cancer in men (AAPC=-1.80, 95% CI: -3.30 to-0.28; P=0.02). We found a higher ASR of stomach cancer in the rural (21.4) than urban (18.1) (P=0.04) population, as well as a significant decreasing trend in its rates (AAPC=-2.14, 95% CI: -3.10to-1.17; P<0.01). The number of new cases of stomach cancer increased by 22.33% (from 215 in 2004 to 263 in 2016), of which 18.1%, 25.1% and -20.9% were due to population size, population aging and risk, respectively. Our findings suggest a higher rate for stomach cancer in eastern areas.

CONCLUSION

We found high incidence rates as well as temporal and geographical diversities in ASR of stomach cancer in Golestan, Iran. Our results showed an increase in the number of new cases, mainly due to population size and aging. Further studies are warranted to determine the risk factors of this cancer in this high-risk population.

Gastric cancer: genome damaged by bugs

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. The role of the microorganisms in gastric tumorigenesis attracts much attention in recent years. These microorganisms include bacteria, virus, and fungi. Among them, Helicobacter pylori (H. pylori) infection is by far the most important risk factor for GC development, with special reference to the early-onset cases. H. pylori targets multiple cellular components by utilizing various virulence factors to modulate the host proliferation, apoptosis, migration, and inflammatory response. Epstein–Barr virus (EBV) serves as another major risk factor in gastric carcinogenesis. The virus protein, EBER noncoding RNA, and EBV miRNAs contribute to the tumorigenesis by modulating host genome methylation and gene expression. In this review, we summarized the related reports about the colonized microorganism in the stomach and discussed their specific roles in gastric tumorigenesis. Meanwhile, we highlighted the therapeutic significance of eradicating the microorganisms in GC treatment.

A novel risk score model for stomach adenocarcinoma based on the expression levels of 10 genes

Stomach adenocarcinoma (STAD) accounts for 95% of cases of malignant gastric cancer, which is the third leading cause of cancer-associated mortality worldwide. The pathogenesis and effective diagnosis of STAD have become popular topics for research in the previous decade. In the present study, high-throughput RNA sequencing expression profiles and clinical data from patients with STAD were obtained from The Cancer Genome Atlas database and were used as a training dataset to screen differentially expressed genes (DEGs). Prognostic DEGs were identified using univariate Cox regression analysis and were further screened by the least absolute shrinkage and selection operator regularization regression algorithm. The resulting genes were used to construct a risk score model, the validation and effectiveness evaluation of which were performed on an independent dataset downloaded from the Gene Expression Omnibus database. Stratified and functional pathway (gene set enrichment) analyses were performed on groups with different estimated prognosis. A total of 92 genes significantly associated with STAD prognosis were obtained by univariate Cox regression analysis, and 10 prognosis-associated DEGs; hemoglobin b, chromosome 4 open reading frame 48, Dickkopf WNT signaling pathway inhibitor 1, coagulation factor V, serpin family E member 1, transmembrane protein 200A, NADPH oxidase organizer 1, C-X-C motif chemokine ligand 3, mannosidase endo-α-like and tripartite motif-containing 31; were selected for the development of the risk score model. The reliability of this prognostic method was verified using a validation set, and the results of multivariate Cox analysis indicated that the risk score may serve as an independent prognostic factor. In functional DEG analysis, eight Kyoto Encyclopedia of Genes and Genomes pathways were identified to be significantly associated with STAD risk factors. Thus, the 10-gene risk score model established in the present study was regarded as credible. This risk assessment tool may help identify patients with a high risk of STAD, and the proposed prognostic mRNAs may be useful in elucidating STAD pathogenesis.

Adherence to general medical checkup and cancer screening guidelines according to self-reported smoking status: Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2012

OBJECTIVES

The National Lung Screening Trial (NLST) revealed that low-dose computed tomography (LDCT) screening could reduce lung cancer mortality in heavy smokers. Lung screening with LDCT was implemented in July 2019 as part of the National Cancer Screening Program in Korea for heavy smokers who meet NLST criteria [smokers aged 55-74 years with 30 pack-years (PY) or more, excluding former smokers with more than 15 years since smoking cessation]. This study evaluated NLST-eligible heavy smokers' adherence to general medical checkup and cancer screening guidelines.

METHODS

Using the Korea National Health and Nutrition Examination Survey (KNHANES) from 2010 to 2012, we compared adherence of Korean adults (55-74 years, n = 5,480) to general medical checkup and cancer (gastric, colorectal, breast, and cervical) screening guidelines according to self-reported smoking status. Smoking and PY data were available, but no data indicating when former smokers ceased smoking were available. Accordingly, smoking status was only classified as NLST (smokers with a history ≥ 30 PY) and non-NLST. Individuals who met NLST criteria were subdivided into current (NLST-current) and former smokers (NLST-former). Multivariable logistic regression was used to evaluate adherence to screening recommendations as a function of the study group (NLST-current, NLST-former, non-NLST) using possible covariates (sociodemographic factors, health-related behaviors, comorbidities, and self-reported health status).

RESULTS

Weighted prevalence of NLST-current was 9.7%, of NLST-former was 9.6%, and of non-NLST was 80.7%. Overall screening rates were 70.7% (medical checkup), 59.1% (stomach cancer), 58.1% (colorectal cancer), 59.1% (breast cancer), and 48.9% (cervical cancer). Adherence to colorectal cancer screening and medical checkup was lower in NLST-current than non-NLST (AOR 0.59; 95% CI 0.44-0.78 for colorectal cancer; AOR 0.70; 95% CI 0.52-0.95 for medical checkup). Screening practices for other cancers were not different.

CONCLUSIONS

Current heavy smokers meeting NLST criteria were less likely to have colorectal cancer screening or general medical checkup. Understanding the screening practices of this target population might enable the development of more effective plans to implement lung screening and improve screening compliance for other cancers.

Smoking, Helicobacter Pylori Serology, and Gastric Cancer Risk in Prospective Studies from China, Japan, and Korea

Smoking is an established risk factor for gastric cancer development. In this study, we aimed to assess prospectively the association of smoking with gastric cancer risk in 1,446 non-cardia gastric cancer cases and 1,796 controls from China, Japan, and Korea with consideration of Helicobacter pylori infection as a potential effect modifier. Applying logistic regression models stratified by study and adjusted for age and sex we found that current, but not former, smoking was significantly associated with gastric cancer risk [OR = 1.33; 95% confidence interval (CI), 1.07-1.65]. However, the association was significant only in H. pylori sero-positive individuals determined by 3 different sero-markers: overall sero-positivity, sero-positivity to the onco-protein CagA, and sero-positivity to the gastric cancer associated sero-marker HP0305 and HP1564. Specifically, a significant interaction was found when stratifying by HP0305/HP1564 (P _interaction = 0.01) with a 46% increased risk of gastric cancer among HP0305/HP1564 sero-positive current smokers (95% CI, 1.10-1.93) as opposed to no increased gastric cancer risk among HP0305/HP1564 sero-negative current smokers (OR = 0.93; 95% CI, 0.65-1.33). We confirmed that current smoking is associated with an increased gastric cancer risk, however, only among individuals that are simultaneously sero-positive for the leading causal factor for gastric cancer, H. pylori.

Development and validation of a risk assessment tool for gastric cancer in a general Japanese population

BACKGROUND

There have been very few reports of risk score models for the development of gastric cancer. The aim of this study was to develop and validate a risk assessment tool for discerning future gastric cancer risk in Japanese.

METHODS

A total of 2444 subjects aged 40 years or over were followed up for 14 years from 1988 (derivation cohort), and 3204 subjects of the same age group were followed up for 5 years from 2002 (validation cohort). The weighting (risk score) of each risk factor for predicting future gastric cancer in the risk assessment tool was determined based on the coefficients of a Cox proportional hazards model in the derivation cohort. The goodness of fit of the established risk assessment tool was assessed using the c-statistic and the Hosmer-Lemeshow test in the validation cohort.

RESULTS

During the follow-up, gastric cancer developed in 90 subjects in the derivation cohort and 35 subjects in the validation cohort. In the derivation cohort, the risk prediction model for gastric cancer was established using significant risk factors: age, sex, the combination of Helicobacter pylori antibody and pepsinogen status, hemoglobin A1c level, and smoking status. The incidence of gastric cancer increased significantly as the sum of risk scores increased (P trend < 0.001). The risk assessment tool was validated internally and showed good discrimination (c-statistic = 0.76) and calibration (Hosmer-Lemeshow test P = 0.43) in the validation cohort.

CONCLUSIONS

We developed a risk assessment tool for gastric cancer that provides a useful guide for stratifying an individual's risk of future gastric cancer.

Gastric cancer & prospects of cancer in Saudi Arabia peninsula

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

Associations of potentially functional variants in IL-6, JAKs and STAT3 with gastric cancer risk in an eastern Chinese population

The interleukin-6 (IL-6)/JAK/STAT3 signaling pathway plays a central role in inflammation-mediated cancers, including gastric cancer (GCa). We evaluated associations between 10 potentially functional single nucleotide polymorphisms (SNPs) of four essential genes in the pathway and GCa risk in a study of 1,125 GCa cases and 1,221 cancer-free controls. We found that a significant higher GCa risk was associated with IL-6 rs2069837G variant genotypes [adjusted odds ratios (OR) = 1.33; 95% confidence interval (CI) = 1.12-1.59 for AG + GG vs. AA)] and JAK1 rs2230587A variant genotypes (adjusted OR = 1.20; 95% CI = 1.02-1.43 for GA + AA vs. GG). We also found that a significant decreased GCa risk was associated with STAT3 rs1053004G variant genotypes (adjusted OR = 0.84; 95% CI = 0.71-0.99 for AG + GG vs. AA). The combined analysis of IL-6 rs2069837G and JAK1 rs2230587A variant risk genotypes revealed that individuals with one-or-two risk genotypes exhibited an increased risk for GCa (adjusted OR = 1.34; 95% CI = 1.13-1.59). Genotypes and mRNA expression correlation analysis using the data from the HapMap 3 database provided further support for the observed risk associations. Larger studies are warranted to validate these findings.

Factors Associated With Metachronous Gastric Cancer Development After Endoscopic Submucosal Dissection for Early Gastric Cancer

GOALS

To clarify the factors associated with metachronous gastric cancer development after endoscopic submucosal dissection (ESD) for early gastric cancer.

BACKGROUND

Patients who undergo ESD for early gastric cancer have an appreciable risk of developing metachronous gastric cancer. However, there have been few reports on the association between life style and the development of such cancer.

STUDY

Patients with early gastric cancer who underwent ESD at our institution between 2003 and 2012 were enrolled. Metachronous gastric cancer was defined as secondary gastric cancer detected >1 year after initial ESD. Factors, including age, gender, body mass index, eradication of Helicobacter pylori, cigarette smoking, drinking, and continuous use of a proton pump inhibitor, associated with metachronous gastric cancer development were evaluated by Cox proportional hazard regression analysis.

RESULTS

A total of 539 patients with a mean 53.6-month follow-up period were analyzed. The 5-year cumulative incidence of secondary gastric cancer was 13.0%. Multivariate analysis exhibited that age of 60 years and above [hazard ratio (95% confidence interval)=4.05 (1.23-13.4)] and cigarette smoking [2.12 (1.19-3.78)] were independent risk factors for metachronous gastric cancer development. Furthermore, ≥20 pack-years of smoking [1.51 (1.03-2.24)] was a significant risk factor with a dose-response relationship (P for trend=0.042). There was no significant association between Helicobacter pylori eradication and metachronous gastric cancer development.

CONCLUSIONS

This is the first study to demonstrate the detailed association between cigarette smoking and metachronous gastric cancer development.

Combination of Helicobacter pylori Antibody and Serum Pepsinogen as a Good Predictive Tool of Gastric Cancer Incidence: 20-Year Prospective Data From the Hisayama Study

BACKGROUND

There is little information regarding whether the combination of Helicobacter pylori (H. pylori) antibody and serum pepsinogen (sPG), which is a marker of the degree of atrophic gastritis, has a discriminatory ability for detecting incident gastric cancer. We examined this issue in a long-term prospective cohort study of a Japanese population.

METHODS

A total of 2446 Japanese community-dwelling individuals aged ≥40 years were stratified into four groups according to baseline H. pylori serological status and sPG: Group A (H. pylori[-], sPG[-]), Group B (H. pylori[+], sPG[-]), Group C (H. pylori[+], sPG[+]), and Group D (H. pylori[-], sPG[+]), and participants were followed up prospectively for 20 years.

RESULTS

During the follow-up, 123 subjects developed gastric cancer. Compared with that in Group A, the cumulative incidence of gastric cancer was significantly increased in Groups B, C, and D, whereas no significant difference was found between Groups C and D. The multivariable-adjusted risk of gastric cancer was significantly increased in Group B (hazard ratio [HR], 4.08; 95% confidence interval [CI], 1.62-10.28) and in Groups C and D combined (HR 11.1; 95% CI, 4.45-27.46). When the multivariable model with H. pylori antibody was changed into that with the combination of H. pylori antibody and sPG, the C statistics for developing gastric cancer increased significantly (0.773 vs 0.732, P = 0.005), and the continuous net reclassification improvement value was 0.591 (P < 0.001).

CONCLUSIONS

Our findings suggest that the combination of H. pylori antibody and sPG is a useful tool for predicting the development of gastric cancer.

Role of Helicobacter pylori in gastric cancer: Updates

Helicobacter pylori (H. pylori) infection is highly prevalent in human, affecting nearly half of the world’s population; however, infection remains asymptomatic in majority of population. During its co-existence with humans, H. pylori has evolved various strategies to maintain a mild gastritis and limit the immune response of host. On the other side, presence of H. pylori is also associated with increased risk for the development of various gastric pathologies including gastric cancer (GC). A complex combination of host genetics, environmental agents, and bacterial virulence factors are considered to determine the susceptibility as well as the severity of outcome in a subset of individuals. GC is one of the most common cancers and considered as the third most common cause of cancer related death worldwide. Many studies had proved H. pylori as an important risk factor in the development of non-cardia GC. Although both H. pylori infection and GC are showing decreasing trends in the developed world, they still remain a major threat to human population in the developing countries. The current review attempts to highlight recent progress in the field of research on H. pylori induced GC and aims to provide brief insight into H. pylori pathogenesis, the role of major virulence factors of H. pylori that modulates the host environment and transform the normal gastric epithelium to neoplastic one. This review also emphasizes on the mechanistic understanding of how colonization and various virulence attributes of H. pylori as well as the host innate and adaptive immune responses modulate the diverse signaling pathways that leads to different disease outcomes including GC.

Polymorphisms in mucin genes in the development of gastric cancer

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. In areas of high prevalence, such as Japan, South Korea and China, most cases of GC are related to Helicobacter pylori (H. pylori), which involves well-characterized sequential stages, including infection, atrophic gastritis, intestinal metaplasia, dysplasia, and GC. Mucins are the most abundant high-molecular-weight glycoproteins in mucus, which is the first line of defense and plays a major role in blocking pathogenic factors. Normal gastric mucosa shows expression of MUC1, MUC5AC and MUC6 that is specific to cell type. However, the specific pattern of MUC1, MUC5AC and MUC6 expression is changed in gastric carcinogenesis, accompanied by de novo expression of secreted MUC2. Recent studies have provided evidence that variations in these mucin genes affect many steps of GC development, such as H. pylori infection, and gastric precancerous lesions. In this review, we focus on studies of the association between polymorphisms in mucin genes and development of GC. This information should be helpful for the early detection, surveillance, and treatment of GC.

Gastric cancer diagnosed after Helicobacter pylori eradication in diabetes mellitus patients

Background

Helicobacter pylori infection is the most important risk factor for gastric cancer, for which eradication therapy is commonly performed. However, gastric cancer is sometimes discovered after successful eradication of H. pylori. Much evidence indicates that diabetes mellitus (DM) is a risk factor for gastric cancer. The incidence and characteristics of gastric cancer diagnosed after H. pylori eradication in DM patients remain to be determined.

Methods

We followed the clinical course of patients who underwent H. pylori eradication therapy at our institution. Endoscopy was performed before and after eradication. We compared the incidence and clinical characteristics of gastric cancer arising in DM and non-DM patients.

Results

In total, 965 patients who underwent successful eradication (518 DM and 447 non-DM patients) were followed-up for an average of 4.5 years. During the follow-up period, 21 gastric cancers were diagnosed (12 in DM patients and 9 in non-DM patients). The incidence of gastric cancer after eradication was not significantly different between DM and non-DM patients (0.485 and 0.482 %/year, respectively). There was no significant difference in the pathology, diameter, depth, location, or treatment of gastric cancer between patients with and without DM.

Conclusion

The incidence and characteristics of gastric cancer occurring after H. pylori eradication were comparable between DM and non-DM patients.

A diversity of cancer incidence and mortality in West Asian populations

BACKGROUND

Western Asia comprises a large proportion of the world population with different ethnicities and religions inhabiting areas of diverse geographic features. The countries of this region have experienced rapid economic growth over the latter half of the 20th century, which continues to this day, resulting in major changes in lifestyle of the population.

OBJECTIVES

The aim of this study was to compare the incidence and mortality of cancer in West Asia using the estimates reported by the International Agency for Research on Cancer (IARC) in Globocan-2012.

METHODS

Countries with high-quality data or national data (based on the definition of the Globocan-2012) were included in the analysis. These included Bahrain, Iran, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, and Turkey. We also found high-quality cancer data from regional cancer registries in 3 Iranian and 3 Turkish provinces. Data on cancer incidence and mortality were collected and described in tables and graphs. Spearman's correlation test was used to assess the correlation between geographic coordinates and the incidence age-standardized rate (ASR; per 100,000 person-years) of cancers.

FINDINGS

Nine countries and 6 regional registries were included. Cancers of the lung (ASR, 33.3), prostate (24.9), bladder (19.1), stomach (16.5), and colorectal (15.9) were the most common malignancies in men. The most common cancers in women were those of the breast (35.4), colorectal (12.1), thyroid (10.3), stomach (9.2), and lung (6.7). The incidence rates of upper gastrointestinal and lung cancers were considerably higher in the northern part of this region, including Turkey and northern Iran compared with southern countries. High incidences of breast, colorectal, prostate, and bladder cancers were found in countries located in the northwest including Jordan, Lebanon, and Turkey.

CONCLUSIONS

The most common cancers differed by country. Consequently, cancer control programs must be tailored to the most common types of cancers in each country. Lack of high-quality data for some West Asian countries was the major limitation of this study. Therefore, as the first step of cancer control programs, it is recommended that well-structured population-based cancer registries be established in all of these countries.

Diversity of clinical implication of B-cell translocation gene 1 expression by histopathologic and anatomic subtypes of gastric cancer

BACKGROUND

Genetic signatures may differ by histopathologic and anatomic subtypes of gastric cancer (GC). B-cell translocation gene 1 (BTG1) was identified as one of genes downregulated in GC tissues from our microarray data.

AIMS

To evaluate the clinical implications of BTG1 expression in GC and the genetic diversity among GC subtypes.

METHODS

BTG1 mRNA expression was analyzed in GC cell lines and 233 pairs of surgical specimens. The mutational and methylation status of BTG1 in GC cell lines was analyzed, and immunohistochemistry was conducted to determine the distribution of BTG1. The pattern and prognostic significance of BTG1 expression were correlated with the three proposed GC subtypes.

RESULTS

BTG1 mRNA was downregulated in 82 % of GC cell lines and in 88 % of clinical GC tissues. Promoter hypermethylation events or sequence mutations were not detected in GC cell lines. The pattern of BTG1 expression as observed by immunohistochemistry was consistent with that of its mRNA. Downregulation of BTG1 mRNA in GCs was significantly associated with shorter disease-specific and recurrence-free survival. Multivariate analysis of disease-specific survival identified downregulation of BTG1 transcription as an independent prognostic factor. BTG1 mRNA expression was more strongly suppressed in proximal nondiffuse and diffuse GC compared with distal nondiffuse GC, and subgroup analysis revealed that BTG1 downregulation led to adverse prognosis, specifically in patients with proximal nondiffuse and diffuse GC.

CONCLUSIONS

Altered expression of BTG1 is a potential biomarker for carcinogenesis and progression of GC, particularly for proximal nondiffuse and diffuse 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.

Prognostic impact of expression and methylation status of DENN/MADD domain-containing protein 2D in gastric cancer

BACKGROUND

Patients with advanced gastric cancer (GC) have an adverse prognosis even after curative resection. Development of novel diagnostic and therapeutic approaches for GC is urgently required.

METHODS

The expression and methylation status of DENN/MADD domain-containing protein 2D (DENND2D), a member of the membrane trafficking proteins, were evaluated in 12 GC cell lines and 112 pairs of surgical specimens. Subgroup analysis based on tumor differentiation, location, and morphology was also performed. Expression and distribution of DENND2D protein were determined by immunohistochemistry.

RESULTS

The majority of GC cell lines (75%) and tissues (79%) showed reduced expression of DENND2D mRNA compared with noncancerous gastric tissues. GC tissues showed a significantly lower mean expression level of mRNA and a higher frequency of promoter hypermethylation of DENND2D than corresponding noncancerous tissues. No significant differences in DENND2D mRNA expression and methylation status were found between GC subtypes categorized by tumor differentiation, location, and morphology. The expression patterns of DENND2D protein were confirmed to be consistent with those of DENND2D mRNA. Downregulation of DENND2D mRNA in GC tissues was significantly associated with factors related to more advanced GC and subsequent adverse prognosis. Among 72 patients who underwent R0 resection, downregulation of DENND2D mRNA in GC tissues was an independent prognostic factor and associated with early recurrence.

CONCLUSIONS

Our results suggested that DENND2D is a putative tumor suppressor gene regulated by promoter hypermethylation in GC. Downregulation of DENND2D can serve as a novel tumor biomarker to predict progression and early recurrence of all types of GC.

Relationship between Helicobacter pylori infection and gastric cancer

Gastric cancer is one of the most common malignancies worldwide, and Helicobacter pylori (H. pylori) infection is the most important risk factor. More than 50% of the world population is infected by H. pylori, but less than 2% develop gastric cancer. Other risk factors like host and environmental factors also play a role in the occurrence of gastric cancer. The pathogenesis of gastric cancer is a multi-factorial and multi-step process, and its outcome is influenced by a combination of host, bacterial, and environmental factors.

The Expression of Melanoma-Associated Antigen D2 Both in Surgically Resected and Serum Samples Serves as Clinically Relevant Biomarker of Gastric Cancer Progression

BACKGROUND

Sensitive biomarkers are necessary for risk classification of patients with gastric cancer (GC), especially ones at risk of distant metastases. Melanoma-associated antigen (MAGE)-D2 has been reported to play a role in the process of cell adhesion and metastatic potential of tumor cells in colorectal cancer. The purpose of this study was to identify a novel clinically relevant biomarker of GC.

METHODS

Expression analysis of MAGE-D2 was conducted in GC cell lines and clinical samples (surgical specimen and serum) in both mRNA and protein level. Correlations between MAGE-D2 expression status and clinicopathological factors were evaluated.

RESULTS

MAGE-D2 mRNA expression levels were similar between GC tissues and the corresponding normal adjacent tissues and were independent of GC differentiation or subtype. In 101 (45 %) of 225 patients, the expression level of MAGE-D2 mRNA was increased in GC tissues compared with the corresponding normal adjacent tissues. Increased expression of MAGE-D2 mRNA in GC tissues was associated with distant metastasis and early recurrence and was an independent prognostic factor (hazard ratio 2.27, 95 % confidence interval 1.39-3.74, P = 0.001). There was a stepwise increase in serum MAGE-D2 level going from healthy volunteers to patients with localized GC and then to those with extended GC (stage IV). Patients with preoperative serum MAGE-D2 levels >130 pg/ml had a more unfavorable prognosis than those with levels ≤130 pg/ml.

CONCLUSION

MAGE-D2 was associated with metastatic potential of GC and may represent a promising biomarker, both in gastric tissues and serum samples, for malignant behavior of GC.

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

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

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

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

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

Genetic and intermediate phenotypic susceptibility markers of gastric cancer in Hispanic Americans: a case-control study

BACKGROUND

Hispanics are the largest nonwhite ethnic group in the US population, and they have higher incidence and mortality rates for gastric cancer (GC) than whites and Asians. Studies have identified several genetic susceptibility loci and intermediate phenotypic biomarkers for GC in whites and Asians. No studies have evaluated genetic susceptibility and intermediate phenotypic biomarkers in Hispanics.

METHODS

In a case-control study of 132 Hispanic patients with GC (cases) and a control group of 125 Hispanics (controls), the authors evaluated the association of 5 single nucleotide polymorphisms (SNPs) that predispose whites and/or Asians to GC and of 2 intermediate phenotypic markers in peripheral blood leukocytes, ie, telomere length and mitochondrial DNA (mtDNA) copy number, with the GC risk.

RESULTS

The variant C allele of the reference SNP rs2294008 in the PSCA gene was associated with a significantly reduced risk of GC (per allele-adjusted odds ratio [aOR], 0.51; 95% confidence interval [CI], 0.33-0.77; P = .002). Leukocyte mtDNA copy numbers were significantly lower in GC cases (mean ± standard deviation, 0.91 ± 0.28) than in controls (1.29 ± 0.42; P < .001). When individuals were dichotomized into high and low mtDNA copy number groups based on the median mtDNA copy number value in the controls, those who had a low mtDNA copy number had a significantly increased risk of GC (aOR, 11.00; 95% CI, 4.79-25.23; P < .001) compared with those who had a high mtDNA copy number. Telomere length was not associated significantly with the risk of GC (aOR, 1.21; 95% CI, 0.65-2.27; P = .551).

CONCLUSIONS

Hispanics share certain genetic susceptibility loci and intermediate phenotypic GC biomarkers with whites and Asians and may also have distinct genetic susceptibility factors.

Helicobacter pylori infection: New pathogenetic and clinical aspects

Helicobacter pylori (H. pylori) infects more than half of the world’s human population, but only 1% to 3% of infected people consequently develop gastric adenocarcinomas. The clinical outcome of the infection is determined by host genetic predisposition, bacterial virulence factors, and environmental factors. The association between H. pylori infection and chronic active gastritis, peptic ulcer disease, gastric cell carcinoma, and B cell mucosa-associated lymphoid tissue lymphoma has been well established. With the exception of unexplained iron deficiency anemia and idiopathic thrombocytopenic purpura, H. pylori infection has no proven role in extraintestinal diseases. On the other hand, there is data showing that H. pylori infection could be beneficial for some human diseases. The unpredictability of the long-term consequences of H. pylori infection and the economic challenge in eradicating it is why identification of high-risk individuals is crucial.

Clinical significance of expression and epigenetic profiling of TUSC1 in gastric cancer

BACKGROUND AND OBJECTIVES

The prognosis of advanced gastric cancer (GC) remains dismal. The aim of this study was to identify a novel tumor suppressor gene (TSG) with repressed transcription by aberrant DNA methylation in GC.

METHODS

The expression and methylation status of tumor suppressor candidate 1 (TUSC1) were evaluated in GC cell lines and 112 pairs of surgical specimens. TUSC1 protein expression and distribution in GC tissue were determined by immunohistochemistry.

RESULTS

The majority of GC cell lines (83%) and GC tissues (82%) showed downregulation of TUSC1 mRNA compared with noncancerous tissues. No significant differences were found in TUSC1 mRNA expression between three GC subtypes categorized by tumor locations and morphology. Reduced expression of TUSC1 mRNA in GC tissues was significantly associated with advanced T stage, vessel invasion and lymph node metastasis, leading to poor prognosis. The expression patterns of TUSC1 protein were confirmed to be consistent with those of TUSC1 mRNA. Sixty-three (57%) of 112 patients showed intragenic hypermethylation of TUSC1 in GC tissues.

CONCLUSIONS

Our results suggested that reduced expression of TUSC1 mRNA was related to poor prognosis and TUSC1 is a putative TSG that is suppressed through intragenic hypermethylation in GC.

Predicting the probability of mortality of gastric cancer patients using decision tree

BACKGROUND

Gastric cancer is the fourth most common cancer worldwide. This reason motivated us to investigate and introduce gastric cancer risk factors utilizing statistical methods.

AIM

The aim of this study was to identify the most important factors influencing the mortality of patients who suffer from gastric cancer disease and to introduce a classification approach according to decision tree model for predicting the probability of mortality from this disease.

METHODS

Data on 216 patients with gastric cancer, who were registered in Taleghani hospital in Tehran,Iran, were analyzed. At first, patients were divided into two groups: the dead and alive. Then, to fit decision tree model to our data, we randomly selected 20% of dataset to the test sample and remaining dataset considered as the training sample. Finally, the validity of the model examined with sensitivity, specificity, diagnosis accuracy and the area under the receiver operating characteristic curve. The CART version 6.0 and SPSS version 19.0 softwares were used for the analysis of the data.

RESULTS

Diabetes, ethnicity, tobacco, tumor size, surgery, pathologic stage, age at diagnosis, exposure to chemical weapons and alcohol consumption were determined as effective factors on mortality of gastric cancer. The sensitivity, specificity and accuracy of decision tree were 0.72, 0.75 and 0.74 respectively.

CONCLUSIONS

The indices of sensitivity, specificity and accuracy represented that the decision tree model has acceptable accuracy to prediction the probability of mortality in gastric cancer patients. So a simple decision tree consisted of factors affecting on mortality of gastric cancer may help clinicians as a reliable and practical tool to predict the probability of mortality in these patients.

Effects of polymorphisms of innate immunity genes and environmental factors on the risk of noncardia gastric cancer

Purpose

Increasing evidence suggests that polymorphisms in innate immunity genes are associated with Helicobacter pylori-induced inflammation and may influence susceptibility in developing noncardia gastric cancer. Therefore, we investigate the effect of polymorphisms of innate immunity genes and interactions with environmental factors in the Korean population.

Materials and Methods

We genotyped four polymorphisms of TLR2 (rs1898830), TLR4 (rs10983755 and rs10759932), and CD14 (rs2569190) in a case-control study of 487 noncardia gastric cancer patients and 487 sex- and age-matched healthy controls. Polytomous logistic regression models were used to detect the effects of genetic polymorphisms and environmental factors, which were stratified by the histological type of gastric cancer.

Results

TLR4 rs10983755 A carriers were found to have higher risk of intestinal-type noncarida gastric cancer than G homozygotes (odds ratio [OR], 1.41; 95% confidence interval [CI], 1.01 to 1.97), but other genetic variants showed no association with the risk of noncardia gastric cancer. Among H. pylori-positive participants, smokers carrying TLR4 rs10983755 A had a higher risk of intestinal-type gastric cancer than nonsmoking TLR4 rs10983755 G homozygotes (OR, 4.28; 95% CI, 2.12 to 8.64). In addition, compared with tap water, other drinking water sources during childhood were found to be associated with the elevated risk of intestinal-type gastric cancer, and these associations were slightly stronger among TLR4 rs10983755 A carriers.

Conclusion

The genetic polymorphisms of innate immunity genes are associated with the development of intestinal-type noncardia gastric cancer and these associations may differ in accordance to an exposure to certain environmental factors.

Effects of polymorphisms of innate immunity genes and environmental factors on the risk of noncardia gastric cancer

PURPOSE

Increasing evidence suggests that polymorphisms in innate immunity genes are associated with Helicobacter pylori-induced inflammation and may influence susceptibility in developing noncardia gastric cancer. Therefore, we investigate the effect of polymorphisms of innate immunity genes and interactions with environmental factors in the Korean population.

MATERIALS AND METHODS

We genotyped four polymorphisms of TLR2 (rs1898830), TLR4 (rs10983755 and rs10759932), and CD14 (rs2569190) in a case-control study of 487 noncardia gastric cancer patients and 487 sex- and age-matched healthy controls. Polytomous logistic regression models were used to detect the effects of genetic polymorphisms and environmental factors, which were stratified by the histological type of gastric cancer.

RESULTS

TLR4 rs10983755 A carriers were found to have higher risk of intestinal-type noncarida gastric cancer than G homozygotes (odds ratio [OR], 1.41; 95% confidence interval [CI], 1.01 to 1.97), but other genetic variants showed no association with the risk of noncardia gastric cancer. Among H. pylori-positive participants, smokers carrying TLR4 rs10983755 A had a higher risk of intestinal-type gastric cancer than nonsmoking TLR4 rs10983755 G homozygotes (OR, 4.28; 95% CI, 2.12 to 8.64). In addition, compared with tap water, other drinking water sources during childhood were found to be associated with the elevated risk of intestinal-type gastric cancer, and these associations were slightly stronger among TLR4 rs10983755 A carriers.

CONCLUSION

The genetic polymorphisms of innate immunity genes are associated with the development of intestinal-type noncardia gastric cancer and these associations may differ in accordance to an exposure to certain environmental factors.

Diet, microbial virulence, and Helicobacter pylori-induced gastric cancer

Gastric adenocarcinoma is a leading cause of cancer-related death worldwide, and Helicobacter pylori infection is one of the strongest known risk factors for this malignancy. H. pylori strains exhibit a high level of genetic diversity, and the risk of gastric cancer is higher in persons carrying certain strain types (for example, those that contain a cag pathogenicity island or type s1 vacA alleles) than in persons carrying other strain types. Additional risk factors for gastric cancer include specific human genetic polymorphisms and specific dietary preferences (for example, a high-salt diet or a diet deficient in fruits and vegetables). Finally, iron-deficiency anemia is a risk factor for gastric cancer. Recent studies have provided evidence that several dietary risk factors for gastric cancer directly impact H. pylori virulence. In this review article, we discuss mechanisms by which diet can modulate H. pylori virulence and thereby influence gastric cancer risk.

Neglected role of hookah and opium in gastric carcinogenesis: a cohort study on risk factors and attributable fractions

A recent study showed an association between hookah/opium use and gastric cancer but no study has investigated the relationship with gastric precancerous lesions. We examined the association between hookah/opium and gastric precancerous lesions and subsequent gastric cancer. In a population-based cohort study, 928 randomly selected, healthy, Helicobacter pylori-infected subjects in Ardabil Province, Iran, were followed for 10 years. The association between baseline precancerous lesions and lifestyle risk factors (including hookah/opium) was analyzed using logistic regression and presented as odds ratios (ORs) and 95% confidence intervals (CIs). We also calculated hazard ratios (HRs) and 95% CIs for the associations of lifestyle risk factors and endoscopic and histological parameters with incident gastric cancers using Cox regression models. Additionally, the proportion of cancers attributable to modifiable risk factors was calculated. During 9,096 person-years of follow-up, 36 new cases of gastric cancer were observed (incidence rate: 3.96/1,000 persons-years). Opium consumption was strongly associated with baseline antral (OR: 3.2; 95% CI: 1.2-9.1) and body intestinal metaplasia (OR: 7.3; 95% CI: 2.5-21.5). Opium (HR: 3.2; 95% CI: 1.4-7.7), hookah (HR: 3.4; 95% CI: 1.7-7.1) and cigarette use (HR: 3.2; 95% CI: 1.4-7.5), as well as high salt intake, family history of gastric cancer, gastric ulcer and histological atrophic gastritis and intestinal metaplasia of body were associated with higher risk of gastric cancer. The fraction of cancers attributable jointly to high salt, low fruit intake, smoking (including hookah) and opium was 93% (95% CI: 83-98). Hookah and opium use are risk factors for gastric cancer as well as for precancerous lesions. Hookah, opium, cigarette and high salt intake are important modifiable risk factors in this high-incidence gastric cancer area.

A functional polymorphism T309G in MDM2 gene promoter, intensified by Helicobacter pylori lipopolysaccharide, is associated with both an increased susceptibility and poor prognosis of gastric carcinoma in Chinese patients

Background

Studies on the association between MDM2 SNP309 (T > G) and gastric cancer have reported conflicting results. Thus, the aim of this study was to investigate whether MDM2 SNP309 is associated with susceptibility and prognosis of gastric carcinoma in Chinese patients.

Methods

Total of 574 gastric carcinoma cases and 574 age- and sex-matched healthy controls were included. MDM2 polymorphism was detected by PCR- RFLP and infection of Helicobacter pylori (H. pylori) by a validated serology test. The functionality of MDM2 SNP309, with or without H. pylori lipopolysaccharide (LPS), was examined by dual-luciferase assay. Kaplan-Meier survival curves were used to evaluate survival. Additional, a meta-analysis was conducted to verity the findings.

Results

MDM2 SNP309G/G genotype was associated with an increased risk of gastric carcinoma when compared with T/T genotype or T carriers (both P < 0.01), and a joint effect between MDM2 SNP309G/G and H. pylori infection was observed to intensify gastric carcinoma risk. SNP309G/G was identified as an independent marker of poor overall survival of carcinoma. In vitro, the luciferase assay further showed an increased transcriptional activity of SNP309G allele compared with SNP309T allele, and the function of polymorphism T309G in MDM2 gene promoter was intensified by H. pylori LPS. Pooled results from the meta-analysis confirmed that SNP309G/G genotype had a significantly increased risk of gastric carcinoma compared with T/T genotype or T carriers, consistent with the case–control findings.

Conclusions

MDM2 SNP309G allele is associated with an increased risk and poor prognosis of gastric carcinoma in Chinese patients. Additional, there is a joint effect of MDM2 SNP309G/G allele and H. pylori infection on gastric carcinoma development, which may attribute to H. pylori LPS.

Polymorphism in the Helicobacter pylori CagA and VacA toxins and disease

Half of the world's population is infected with Helicobacter pylori and approximately 20% of infected individuals develop overt clinical disease such as ulcers and stomach cancer. Paradoxically, despite its classification as a class I carcinogen, H. pylori has been shown to be protective against development of asthma, allergy, and esophageal disease. Given these conflicting roles for H. pylori, researchers are attempting to define the environmental, host, and pathogen interactions that ultimately result in severe disease in some individuals. From the bacterial perspective, the toxins, CagA and VacA, have each been shown to be polymorphic and to contribute to disease in an allele-dependent manner. Based on the notable advances that have recently been made in the CagA field, herein we review recent studies that have begun to shed light on the role of CagA polymorphism in H. pylori disease. Moreover, we discuss the potential interaction of CagA and VacA as a mediator of gastric disease.

Cigarette experimentation and the population attributable fraction for associated genetic and non-genetic risk factors

BACKGROUND

We, and others, have shown that experimenting with cigarettes is a function of both non-genetic and genetic factors. In this analysis we ask: how much of the total risk of experimenting with cigarettes, among those who had not experimented with cigarettes when they enrolled in a prospective cohort, is attributable to genetic factors and to non-genetic factors?

METHODS

Participants (N = 1,118 Mexican origin youth), recruited from a large population-based cohort study in Houston, Texas, provided prospective data on cigarette experimentation over three years. Non-genetic data were elicited twice - baseline and follow-up. Participants were genotyped for 672 functional and tagging variants in the dopamine, serotonin and opioid pathways.

RESULTS

In the overall model, the adjusted combined non-genetic PAF was 71.2% and the adjusted combined genetic PAF was 58.5%. Among committed never smokers the adjusted combined non-genetic PAF was 67.0% and the adjusted combined genetic PAF was 53.5%. However, among cognitively susceptible youth, the adjusted combined non-genetic PAF was 52.0% and the adjusted combined genetic PAF was 68.4%.

CONCLUSIONS

Our results suggest there may be differences in genotypes between youth who think they will try cigarettes in the future compared to their peers who think they will not and underscore the possibility that the relative influence of genetic vs. non-genetic factors on the uptake of smoking may vary between these two groups of youth.

IMPACT

A clearer understanding of the relative role of genetic vs. non-genetic factors in the uptake of smoking may have implications for the design of prevention programs.

Optimal cutoff value of the serum pepsinogen level for prediction of gastric cancer incidence: the Hisayama Study

BACKGROUND

Serum pepsinogen (sPG) levels have been established as a good marker of chronic atrophic gastritis and the sequential occurrence of gastric cancer. However, there have been few prospective investigations which investigated the predictive performance of sPG for future gastric cancer incidence.

SUBJECTS AND METHODS

We prospectively followed-up a total of 2446 community-dwelling Japanese aged ≥ 40 years for 10 years and used the Youden's index to determine the cutoff values of the pepsinogen I level and pepsinogen I/II ratio to accurately discriminate gastric cancer events. Predictive performance of sPG was assessed by ROC curve.

RESULTS

During the follow-up, 69 subjects developed gastric cancer. The most predictive sPG test criteria were determined to be a pepsinogen I level ≤ 59 ng/ml and pepsinogen I/II ratio ≤ 3.9. The sensitivity and specificity of these criteria to discriminate the actual occurrence of gastric cancer were 71.0% and 69.2%, respectively. The area under the ROC curve for gastric cancer occurrence increased significantly by adding the sPG test to the model that included the status of Helicobater pylori infection and other potential risk factors (from 0.742 to 0.809; p for difference in the area < 0.001).

CONCLUSIONS

This study determined the optimal sPG test criteria for predicting gastric cancer occurrence over 10 years in a general Japanese population. These criteria would be effective to screen for individuals at high risk of this disease.

Estimating the prevalence of active Helicobacter pylori infection in a rural community with global positioning system technology-assisted sampling

We investigated a possible outbreak of H. pylori in a rural Northern Plains community. In a cross-sectional survey, we randomly sampled 244 households from a geocoded emergency medical system database. We used a complex survey design and global positioning system units to locate houses and randomly selected one eligible household member to administer a questionnaire and a 13C-urea breath test for active H. pylori infection (n = 166). In weighted analyses, active H. pylori infection was detected in 55·0% of the sample. Factors associated with infection on multivariate analysis included using a public drinking-water supply [odds ratio (OR) 12·2, 95% confidence interval (CI) 2·9-50·7] and current cigarette smoking (OR 4·1, 95% CI 1·7-9·6). People who lived in houses with more rooms, a possible indicator of decreased crowding in the home, were less likely to have active H. pylori infections (OR 0·7, 95% CI 0·5-0·9 for each additional room).

Effect of PSCA gene polymorphisms on gastric cancer risk and survival prediction: A meta-analysis

Previous studies have shown that two single-nucleotide polymorphisms (SNPs) in PSCA (rs2976392 and rs2294008) are associated with gastric cancer (GC), but the results are conflicting. Additionally, the prognostic value of PSCA gene polymorphisms for GC patients is unknown. We performed a meta-analysis using 9 eligible case-control studies to investigate the association between PSCA polymorphisms and GC risk, and additionally investigated the prognostic value of PSCA polymorphisms for GC patients with two eligible studies. The association was measured using random-effect or fixed-effect odds ratios (ORs) combined with 95% confidence intervals (CIs) according to the heterogeneity of the studies. We found that rs2294008 (dominant model: OR, 1.44; 95% CI, 1.16-1.79) and rs2976392 (dominant model: OR, 1.41; 95% CI, 0.98-2.04) polymorphisms were associated with increased risk of GC, although the association of rs2976392 was not statistically significant. For rs2294008, the associations were all consistently significant among the different subgroups stratified by ethnicity and tumor location, but not significant in intestinal or diffuse subtypes. For rs2976392, the associations were consistently significant for the intestinal, diffuse and non-cardia subtypes, but not significant for the cardia subtype. Furthermore, two eligible studies reported inverse results of PCSA in predicting the survival of GC patients (HR, 0.75; 95% CI, 0.59-0.96; and HR, 2.12; 95% CI, 1.22-3.69, respectively). In conclusion, PSCA gene polymorphisms are associated with increased risk of GC and are correlated with the prognosis of GC patients. Future studies are required to evaluate the molecular mechanisms of PSCA polymorphisms in GC and validate the prognostic value in a larger number of patients.

Cyclooxygenase-2 and gastric cancer

Gastric cancer remains a leading cause of cancer-related deaths worldwide, although its incidence has been steadily declining during recent decades. Expression of cyclooxygenase-2 (COX-2) is elevated in gastric carcinomas and in their precursor lesions. COX-2 expression associates with reduced survival in gastric cancer patients, and it has also been shown to be an independent factor of poor prognosis. Several molecular mechanisms are involved in the regulation of COX-2 expression in gastric cancer cell lines, including signal transduction pathways activated by Helicobacter pylori. In gastric tumor models in vivo the role of COX-2 seems to be predominantly to facilitate tumor promotion and growth.

White blood cell count and risk of gastric cancer incidence in a general Japanese population: the Hisayama study

The authors examined the association between white blood cell (WBC) count and the development of gastric cancer in a 19-year follow-up study of 2,558 Japanese subjects aged ≥40 years (1988-2007). The subjects were stratified into 4 groups according to baseline WBC quartile (≤4.4, 4.5-5.2, 5.3-6.3, or ≥6.4 × 10(3) cells/μL). During follow-up, 128 subjects developed gastric cancer. The age- and sex-adjusted incidence of gastric cancer increased linearly with higher WBC level: 1.7, 2.6, 3.9, and 5.4 per 1,000 person-years, respectively, for the 4 quartile groups (P for trend < 0.01). The risk of gastric cancer was 2.22-fold (95% confidence interval: 1.19, 4.14) higher in the highest WBC quartile group than in the lowest group after adjustment for confounding factors. With respect to Helicobacter pylori infection status, H. pylori-seropositive subjects in the highest WBC quartile group showed a significantly greater risk of gastric cancer than those in the lower 3 quartile groups, whereas such an association was not observed in H. pylori-seronegative subjects. There was no evidence of heterogeneity in the association (P for heterogeneity = 0.65). The study findings suggest that higher WBC levels are a risk factor for gastric cancer, especially in subjects with H. pylori infection.