Helicobacter pylori seropositivity and subsite-specific gastric cancer risks in Linxian, China

The global prevalence of gastric cancer in Helicobacter pylori-infected individuals: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is a gastrointestinal pathogen that infects around half of the world's population. H. pylori infection is the most severe known risk factor for gastric cancer (GC), which is the second highest cause of cancer-related deaths globally. We conducted a systematic review and meta-analysis to assess the global prevalence of GC in H. pylori-infected individuals.

METHODS

We performed a systematic search of the PubMed, Web of Science, and Embase databases for studies of the prevalence of GC in H. pylori-infected individuals published from 1 January 2011 to 20 April 2021. Metaprop package were used to calculate the pooled prevalence with 95% confidence interval. Random-effects model was applied to estimate the pooled prevalence. We also quantified it with the I2 index. Based on the Higgins classification approach, I2 values above 0.7 were determined as high heterogeneity.

RESULTS

Among 17,438 reports screened, we assessed 1053 full-text articles for eligibility; 149 were included in the final analysis, comprising data from 32 countries. The highest and lowest prevalence was observed in America (pooled prevalence: 18.06%; 95% CI: 16.48 - 19.63; I2: 98.84%) and Africa (pooled prevalence: 9.52%; 95% CI: 5.92 - 13.12; I2: 88.39%). Among individual countries, Japan had the highest pooled prevalence of GC in H. pylori positive patients (Prevalence: 90.90%:95% CI: 83.61-95.14), whereas Sweden had the lowest prevalence (Prevalence: 0.07%; 95% CI: 0.06-0.09). The highest and lowest prevalence was observed in prospective case series (pooled prevalence: 23.13%; 95% CI: 20.41 - 25.85; I2: 97.70%) and retrospective cohort (pooled prevalence: 1.17%; 95% CI: 0.55 - 1.78; I 2: 0.10%).

CONCLUSIONS

H. pylori infection in GC patients varied between regions in this systematic review and meta-analysis. We observed that large amounts of GCs in developed countries are associated with H. pylori. Using these data, regional initiatives can be taken to prevent and eradicate H. pylori worldwide, thus reducing its complications.

Interleukin-33 as a Potential Therapeutic Target in Gastric Cancer Patients: Current Insights

Gastric cancer is a significant global health problem as it is the fifth most prevalent cancer worldwide and the fourth leading cause of cancer-related mortality. While cytotoxic chemotherapy remains the primary treatment for advanced GC, response rates are limited. Recent progresses, focused on molecular signalling within gastric cancer, have ignited new hope for potential therapeutic targets that may improve survival and/or reduce the toxic effects of traditional therapies. Carcinomas are generally initiated when critical regulatory genes get mutated, but the progression to malignancy is usually supported by the non-neoplastic cells that create a conducive environment for transformation and progression to occur. Interleukin 33 (IL-33) functions as a dual activity cytokine as it is also a nuclear factor. IL-33 is usually present in the nuclei of the cells. Upon tissue damage, it is released into the extracellular space and binds to its receptor, suppression of tumorigenicity 2 (ST2) L, which is expressed on the membranes of the target cells. IL-33 signalling activates the T Helper 2 (Th2) immune response among other responses. Although the studies on the role of IL-33 in gastric cancer are still in the early stages, they have revealed potentially important (though sometimes conflicting) functions or roles in cancer development and progression. The pro-tumorigenic roles include induction and the recruitment of tumor-associated immune cells, promoting metaplasia progression, and inducing stem cell like and EMT properties in gastric cancer cells. Therapeutic interventions to disrupt these functions may provide a unique strategy for gastric cancer prevention and treatment. This review aims to provide a summary of the role of IL-33 in GC, state its multiple functions in relation to GC, and show potential avenues for promising therapeutic investigation.

A systematic review and meta-analysis on the relative and attributable risk of Helicobacter pylori infection and cardia and non-cardia gastric cancer

INTRODUCTION

This study aimed to update the association between Helicobacter pylori (H. pylori) infection and gastric cancer (GC).

METHODS

We searched PubMed, Embase, and Cochrane Library from 1990 to December 2021 to identify prospective studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were summarized to validate the relationship between H. pylori infection and GC.

RESULTS

Including 27 studies, findings indicated a strong link between H. pylori and non-cardia gastric cancer (NCGC) in both Europe/North America (OR=5.37, 95%CI:4.39-6.57) and Asia (OR = 2.50, 95%CI:1.89-3.32), and a positive association with cardia gastric cancer (CGC) in Asia (OR = 1.74, 95%CI:1.38-2.19), but an inverse association in European/American populations (OR = 0.64, 95%CI: 0.51 to 0.79). Furthermore, the strength of association was greater in studies that detected H. pylori by immunoblotting versus ELISA, and also in studies testing for H. pylori detection further back in time prior to cancer diagnosis (Ptrend<0.05). Approximately 79% of NCGC in Asia and 87% in Europe/North America, along with 62% of CGC in Asia, could be attributable to H. pylori infection.

CONCLUSIONS

The meta-analysis supports the significant attributable risk of H. pylori infection for GC and underscores the potential impact of targeting H. pylori in GC prevention programs.

PROSPERO REGISTRATION

CRD42021274120.

Partners in crime: The Lewis Y antigen and fucosyltransferase IV in Helicobacter pylori-induced gastric cancer

Helicobacter pylori (H. pylori) is a major causative agent of chronic gastritis, gastric ulcer and gastric carcinoma. H. pylori cytotoxin associated antigen A (CagA) plays a crucial role in the development of gastric cancer. Gastric cancer is associated with glycosylation alterations in glycoproteins and glycolipids on the cell surface. H. pylori cytotoxin associated antigen A (CagA) plays a significant role in the progression of gastric cancer through post-translation modification of fucosylation to develop gastric cancer. The involvement of a variety of sugar antigens in the progression and development of gastric cancer has been investigated, including type II blood group antigens. Lewis Y (LeY) is overexpressed on the tumor cell surface either as a glycoprotein or glycolipid. LeY is a difucosylated oligosaccharide, which is catalyzed by fucosyltransferases such as FUT4 (α1,3). FUT4/LeY overexpression may serve as potential correlative biomarkers for the prognosis of gastric cancer. We discuss the various aspects of H. pylori in relation to fucosyltransferases (FUT1-FUT9) and its fucosylated Lewis antigens (LeY, LeX, LeA, and LeB) and gastric cancer. In this review, we summarize the carcinogenic effect of H. pylori CagA in association with Le^Y and its synthesis enzyme FUT4 in the development of gastric cancer as well as discuss its importance in the prognosis and its inhibition by combination therapy of anti-Le^Y antibody and celecoxib through MAPK signaling pathway preventing gastric carcinogenesis.

Oral Health and Risk of Upper Gastrointestinal Cancers in a Large Prospective Study from a High-risk Region: Golestan Cohort Study

Tooth loss and periodontal disease have been associated with several cancers, and poor oral health may be an important risk factor for upper gastrointestinal (UGI, i.e., esophageal and gastric) cancers. We assessed the relationship between oral health and UGI cancers using a large prospective study of over 50,000 adults living in Golestan Province, Iran, a high-incidence area for these cancers. Hazard ratios (HRs) and 95% confidence intervals (CI) were estimated for the association between three different measures of oral health [frequency of tooth brushing; number of missing teeth; and the sum of decayed, missing, and filled teeth (DMFT)] and UGI cancers. During a median follow-up duration of 13 years, there were 794 incident UGI cancers (396 esophageal and 398 gastric cancers). Daily tooth brushing was associated with a decreased risk of developing both esophageal (HR = 0.670; 95% CI: 0.486-0.924) and gastric (HR = 0.741; 95% CI: 0.544-1.01) cancers (combined UGI cancer HR = 0.697; 95% CI: 0.558-0.871) compared with never brushing. Tooth loss in excess of the loess smoothed, age- and sex-specific median number of teeth lost was significantly associated with esophageal (HR = 1.64; 95% CI: 1.08-2.47) and gastric cancers (HR = 1.58; 95% CI: 1.05-2.38). There were some adverse associations between DMFT and UGI cancers but most were not statistically significant. These results suggest increased risk of developing UGI cancers among individuals with poor oral health, and those who do not perform regular oral hygiene. PREVENTION RELEVANCE: Poor oral health is associated with the risk of upper gastrointestinal cancers, and oral hygiene practices may help prevent these cancers.

Gastrointestinal cancers in China, the USA, and Europe

Gastrointestinal (GI) cancers, including colorectal cancer, gastric cancer, and esophageal cancer, are a major medical and economic burden worldwide and have the largest number of new cancer cases and cancer deaths each year. Esophageal and gastric cancers are most common in developing countries, while colorectal cancer forms the major GI malignancy in Western countries. However, a great shift in the predominant GI-cancer type is happening in countries under economically transitioning and, at the same time, esophageal and gastric cancers are reigniting in Western countries due to the higher exposure to certain risk factors. The development of all GI cancers is highly associated with lifestyle habits and all can be detected by identified precancerous diseases. Thus, they are all suitable for cancer screening. Here, we review the epidemiological status of GI cancers in China, the USA, and Europe; the major risk factors and their distribution in these regions; and the current screening strategies.

Microbiological evidences for gastric cardiac microflora dysbiosis inducing the progression of inflammation

BACKGROUND AND AIM

Nowadays, anti-inflammation treatment is a promising approach for preventing tumorigenesis, and human microflora is closely related to inflammation. This study aimed to investigate the gastric cardiac microbiome and identify inflammation-related microorganisms for gastric cardiac inflammation.

METHODS

We performed 16S rRNA sequencing on a total of 11 healthy individuals and 89 individuals with different degree of gastric cardiac inflammation. Immunohistochemistry was used for verifying candidate bacteria. Phylogenetic reconstruction of unobserved states (picrust) was used for predicting the pathways involved by cardiac microflora.

RESULTS

The resident phyla in normal were Proteobacteria, Firmicutes, Bacteroides, and Actinobacteria, and the dominant genus in normal were Halomonas, shewanella, and Comamonas. In the progression of gastric cardiac inflammation, the diversity of cardiac microflora did not change (P > 0.05). However, the composition structure of cardiac microflora varied between healthy and inflamed tissues (P < 0.05). Meanwhile, there were 64 species parallel increased with inflammation degree, especially Helicobacter pylori, Lactobacillus spp. Additionally, inflammation-related species were detected (P < 0.05), including H. pylori, Acinetobacter ursingii, and Streptococcus agalactiae. Higher H. pylori colonization was positively related to the progression of cardiac inflammation (γ coefficient = 0.678, P < 0.001), and it also influenced the cardiac microbial community structure. Cardiac microflora also participated in DNA repair pathways and is affected by the relative abundance of H. pylori (P < 0.0001).

CONCLUSIONS

Cardiac microflora dysbiosis, especially the increasing of the relevant abundance of H. pylori, promotes the progression of cardiac inflammation.

Helicobacter pylori and gastric cardia cancer: What do we know about their relationship?

The incidence of gastric cardia cancer is increasing around the world. Since the discovery of Helicobacter pylori (H. pylori), numerous studies have proved that it is a causative factor for many kinds of digestive system tumors. Although the literature on gastric cardia cancer and H. pylori is not scarce, there are still many controversies on the relationship between gastric cardia cancer and H. pylori. Many Western research results showed that there was a negative or no correlation between H. pylori infection and gastric cardia cancer, but in several studies in Asian countries, such as China, H. pylori was demonstrated to be a risk factor for gastric cardia cancer. Therefore, we intended to analyze the related studies to find out the relationship between H. pylori and gastric cardia cancer and find out the causes of the above controversies. We also conducted a meta-analysis of the relationship between cagA positive expression of H. pylori and gastric cardia cancer, to find out whether there is an effect between those two. The primary purpose of this paper was to explore the relationship between gastric cardia cancer and H. pylori. Through analysis, the study showed the reasons for the controversies mentioned above: (1) Geographical factors could affect the relationship between H. pylori and gastric cardia cancer; (2) The definition of gastric cardia cancer in various studies is inconsistent. The result of a meta-analysis about the relationship between H. pylori virulence factor cagA and gastric cardia cancer showed that there was no relationship between these two.

One Size Does Not Fit All: Marked Heterogeneity in Incidence of and Survival from Gastric Cancer among Asian American Subgroups

BACKGROUND

Asian Americans are at higher risk for noncardia gastric cancers (NCGC) relative to non-Hispanic Whites (NHW). Asian Americans are genetically, linguistically, and culturally heterogeneous, yet have mostly been treated as a single population in prior studies. This aggregation may obscure important subgroup-specific cancer patterns.

METHODS

We utilized data from 13 regional United States cancer registries from 1990 to 2014 to determine secular trends in incidence and survivorship from NCGC. Data were analyzed for NHWs and the six largest Asian American subgroups: Chinese, Japanese, Filipino, Korean, Vietnamese, and South Asian (Indian/Pakistani).

RESULTS

There exists substantial heterogeneity in NCGC incidence between Asian subgroups, with Koreans (48.6 per 100,000 person-years) having seven-fold higher age-adjusted incidence than South Asians (7.4 per 100,000 person-years). Asians had generally earlier stages of diagnosis and higher rates of surgical resection compared with NHWs. All Asian subgroups also demonstrated higher 5-year observed survival compared with NHWs, with Koreans (41.3%) and South Asians (42.8%) having survival double that of NHWs (20.1%, P < 0.001). In multivariable regression, differences in stage of diagnosis and rates of resection partially explained the difference in survivorship between Asian subgroups.

CONCLUSIONS

We find substantial differences in incidence, staging, histology, treatment, and survivorship from NCGC between Asian subgroups, data which challenge our traditional perceptions about gastric cancer in Asians. Both biological heterogeneity and cultural/environmental differences may underlie these findings.

IMPACT

These data are relevant to the national discourse regarding the appropriate role of gastric cancer screening, and identifies high-risk racial/ethnic subgroups who many benefit from customized risk attenuation programs.

Helicobacter pylori Is Associated With Precancerous and Cancerous Lesions of the Gastric Cardia Mucosa: Results of a Large Population-Based Study in China

Background: Helicobacter pylori (H. pylori) is widely accepted to be the most important cause of gastric non-cardia adenocarcinoma (GNCA), while its role in the development of gastric cardia adenocarcinoma (GCA) is not well-defined. We aimed to investigate current H. pylori infection in relation to the severity of both precancerous and cancerous lesions of the gastric cardia in an Asian population at high risk of GCA. Methods: A population-based cross-sectional study was conducted in Linzhou County, Henan Province, China. Two thousand three (2,003) randomly selected participants with data on current H. pylori infection, assayed by 13C-urea breath test (13C-UBT), and a sequence of histological diagnoses of the gastric cardia mucosa were analyzed. Results: Of 2,003 subjects, 828 (41.33%) were currently infected with H. pylori. The prevalence of current H. pylori infection increased with increasing severity of histological lesions, from 34.12% in subjects with normal gastric cardia mucosa to 52.17% in subjects with gastric cardia high-grade intraepithelial neoplasia (CHIN)/ gastric cardia adenocarcinoma (GCA) (P for trend <0.001). With H. pylori-negative subjects as the reference category, H. pylori-positive subjects had statistically significant elevated adjusted prevalence odds ratios (PORs) for each of the histological lesions. The PORs (95% CI) were 2.15 (1.74-2.64), 3.46 (2.08-5.75), 2.78 (1.90-4.07), and 3.05 (1.30-7.17) for subjects with carditis, cardia intestinal metaplasia (CIM), cardia low-grade intraepithelial neoplasia (CLIN), and CHIN/GCA), respectively. The associations remained when subjects with abnormal stomach non-cardia mucosa were excluded. Conclusions: This large epidemiologic study demonstrates a positive association between current H. pylori infection and the severity of both precancerous and cancerous lesions of the gastric cardia in an Asian population at high risk of GCA. These findings suggest that H. pylori infection may play a role throughout both early- and late-stage development of GCA.

Gastric cancer: Epidemiology, risk factors and prevention strategies

Gastric cancer (GC) is a global health problem, with more than 1 million people newly diagnosed with GC worldwide each year. GC is more prevalent in less developed countries than in more developed countries. About half of all GC cases worldwide occur in East Asia, notably China. Globally, overall incidence rates of GC are declining, which is potentially attributed to a decrease in Helicobacter pylori (H. pylori) infection and the use of refrigeration to preserve foods rather than salt. GC is a multifactorial disease, and its occurrence and development were impacted by environmental and genetic factors. H. pylori infection is the primary risk factor for GC, especially for non-cardia. The prognosis of GC is poor due to stages at the first diagnosis. The 5-year survival rate is less than 10% when patients are diagnosed at an advanced stage, but the rate is as high as 85% if patients are detected at an earlier stage. Endoscopic screening can potentially prevent GC by early diagnosis and early treatment and has been widely adopted in screening programs in East Asian countries, such as Japan and Korea. This review summarizes updated epidemiological aspects, risk factors, and prevention strategies of GC in recent years to help researchers determine the most effective intervention strategies for reducing risk of GC.

Serologic Profile of Antiparietal Cell Antibodies, Pepsinogens, and H. pylori and Risk of Upper Gastrointestinal Cancer: A Nested Case-Control Study in China

BACKGROUND

Autoimmune gastritis is understudied and possibly associated with gastric noncardia adenocarcinoma (GNCA) and esophageal squamous cell carcinoma (ESCC) in Western populations when it presents as pernicious anemia.

METHODS

A nested case-control study within a Chinese cohort included 100 ESCC, 200 gastric cardia adenocarcinoma (GCA), and 200 GNCA cases diagnosed between 1986 and 2001 and 400 controls. Serostatus of antiparietal cell antibodies (APCA), Helicobacter pylori antibodies, and pepsinogens were measured using commercial kits and serum collected at baseline. We used logistic regression to calculate odds ratios (OR) and 95% confidence interval (CI) for associations between serologic biomarkers and cancer risk adjusted for numerous potential confounders.

RESULTS

There was an average interval of 8 years between baseline blood draw and cancer diagnosis. The baseline prevalence of APCA seropositivity was 10.0% and 14.5% in subjects who developed GCA and GNCA, respectively. APCA seropositivity was inversely associated with later development of GCA (OR = 0.42; 95% CI, 0.24-0.75), but not significantly associated with later development of GNCA (OR = 0.82; 95% CI, 0.50-1.36) or ESCC (OR = 1.05; 95% CI, 0.58-1.88). APCA seropositivity was significantly associated with low pepsinogen I/II ratios (OR = 3.69; 95% CI, 1.66-8.21), and individuals with low pepsinogen I/II ratios who were seronegative for APCA had the highest risk of both GCA and GNCA.

CONCLUSIONS

APCA seropositivity measured years prior to diagnosis was associated with prevalent atrophic gastritis but inversely associated with incident GCA in this Chinese population.

IMPACT

APCA may contribute to a growing list of serologic markers that can improve risk stratification for gastric cancer.

Serum ghrelin and esophageal and gastric cancer in two cohorts in China

Ghrelin is a hormone produced in the oxyntic glands of the stomach. Previous work by our group has suggested that serum ghrelin concentrations are inversely associated with gastric and esophageal cancer risk. We measured ghrelin concentrations in the Linxian General Population Nutrition Intervention Trial (NIT), and the Shanghai Women's Health Study (SWHS). In NIT, we analyzed serum samples from 298 esophageal squamous cell carcinoma (ESCC) cases, 518 gastric cardia adenocarcinoma (GCA) cases, 258 gastric noncardia adenocarcinoma (GNCA) cases and 770 subcohort controls (case-cohort). In SWHS, we measured ghrelin in plasma samples from 249 GNCA cases and 498 matched controls (nested case-control). Ghrelin was measured using radioimmunoassay. In NIT and SWHS, low ghrelin concentrations were associated with an increased risk of developing GNCA and GCA. The hazard ratio (HR _Q1:Q4 ) for GNCA in NIT was 1.35 (95% CI: 0.89-2.05; p-trend = 0.02); the odds ratio in SWHS was 1.66 (95% CI: 1.02-2.70; p-trend = 0.06). Low ghrelin was associated with a twofold increase of GCA (HR _Q1:Q4 = 2.00, 95% CI: 1.45-2.77; p-trend<0.001). In contrast, a lower risk of ESCC (NIT ESCC HR _Q1:Q4 = 0.65, 95% CI: 0.45-0.92; p-trend = 0.02) was found in NIT. Low baseline ghrelin concentrations were associated with an increased risk for GNCA and GCA in the NIT and the SWHS. In contrast, low ghrelin concentrations at baseline were associated with a reduced risk of developing ESCC in the NIT. Ghrelin may be an early marker of future cancer risk for developing upper gastrointestinal cancer in regions of high incidence.

Microbial characterization of esophageal squamous cell carcinoma and gastric cardia adenocarcinoma from a high-risk region of China

BACKGROUND

Little is known about the microbiota and upper gastrointestinal tumors. Esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) occur in adjacent organs, co-occur geographically, and share many risk factors despite being of different tissue types.

METHODS

This study characterized the microbial communities of paired tumor and nontumor samples from 67 patients with ESCC and 36 patients with GCA in Henan, China. DNA was extracted with the MoBio PowerSoil kit. The V4 region of the 16S ribosomal RNA gene was sequenced with MiniSeq and was processed with Quantitative Insights Into Microbial Ecology 1. The linear discriminant analysis effect size method was used to identify differentially abundant microbes, the Wilcoxon rank-sum test was used to test α diversity differences, and permutational multivariate analysis of variance was used to test for differences in β diversity.

RESULTS

The microbial environments of ESCC and GCA tissues were all composed primarily of Firmicutes, Bacteroidetes, and Proteobacteria. ESCC tumor tissues contained more Fusobacterium (3.2% vs 1.3%) and less Streptococcus (12.0% vs 30.2%) than nontumor tissues. GCA nontumor tissues had a greater abundance of Helicobacter (60.5% vs 11.8%), which may have been linked to the lower α diversity (58.0 vs 102.5; P = .0012) in comparison with tumor tissues. A comparison of ESCC and GCA nontumor tissues showed that the microbial composition (P = .0040) and the α diversity (87.0 vs 58.0; P = .00052) were significantly different. No significant differences were detected for α diversity within ESCC and GCA tumor tissues.

CONCLUSIONS

This study showed differences in the microbial compositions of paired ESCC and GCA tumor and nontumor tissues and differences by organ site. Large-scale, prospective cohort studies are needed to confirm these findings.

Endoplasmic reticulum proteostasis control and gastric cancer

The endoplasmic reticulum (ER) is the primary organelle responsible for the synthesis, modification, folding and secretion of proteins, especially in specialized secretory cells. It also contributes to the maintenance of cellular functions, such as Ca²⁺ storage, lipogenesis, gluconeogenesis, and organelle biogenesis. Cellular stress conditions, such as glucose deprivation, hypoxia and disturbance of Ca²⁺ homeostasis, may increase the risk of protein misfolding and perturb proteostasis. This activates ER stress and triggers the unfolded protein response (UPR), leading to either the restoration of homeostasis or cell death. ER stress and UPR have been shown to play crucial roles in the pathogenesis, progression and treatment response of various cancers. In gastric cancer (GC), one of the most aggressive cancer types, critical functions of ER stress signaling have also started to emerge. Herein, we summarize the current knowledge linking ER stress and UPR to GC; we also discuss the possible nodes of therapeutic intervention and propose directions of future research.

H. pylori infection and gastric cancer in Bangladesh: a case-control study

Background:

Like that of other Asian countries gastric cancer (GC) is also a leading cancer in Bangladesh and also a cause for cancer-related mortality. Infection with Helicobacter pylori (H. pylori) is the strongest recognized risk factor for gastric adenocarcinoma. The infection is also prevalent in common people. This case-control study was carried out to find an association between GC and H. pylori infection in the community.

Materials and Methods:

To evaluate association of H. pylori and carcinoma of stomach this study was conducted at National Institute of Cancer Research & Hospital, Dhaka from January 2013 to December 2014. H. pylori status was determined serologically by using H. pylori kit in the department of Biochemistry laboratory of Bangabandhu Sheikh Mujib Medical University. In total, 114 patients with GC and 520 patients not having GC were studied as controls. Logistic regression method was used to calculate the odds ratio.

Results:

Significantly more patients in the case group (86.8%) were found to be seropositive for H. pylori antigen in contrast to the control group (67.5%). All of the cases in the present study were in advanced stage. No significant association between H. pylori seropositivity and tumor location was found. It was noted that undifferentiated gastric carcinoma had slightly more association with H. pylori infection. Younger H. pylori–infected patients had been found to be at higher relative risk for GC than older patients.

Conclusion:

As there is a strong association found between GC and H. pylori infection special emphasis to eradicate H. pylori infection might reduce the incidence of this dreadly disease.

A global burden of gastric cancer: the major impact of China

Gastric cancer (GC) is a highly aggressive cancer and a major cause of cancer-related deaths worldwide. Approximately half of the world's GC cases and deaths occur in china. GC presents challenges in early diagnosis and effective therapy due to a lack of understanding of the underlying molecular biology. The primary goals of this review are to outline current GC research in china and describe future trends in this field. Areas covered: This review mainly focuses on a series of GC-related advances China has achieved. Considerable progress has been made in understanding the role of H. pylori in GC by a series of population-based studies in well-established high-risk areas; A few germline and somatic alterations have been identified by 'omics' studies; Studies on the mechanisms of malignant phenotypes have helped us to form an in-depth understanding of GC and advance drug discovery. Moreover, identification of potential biomarkers and targeted therapies have facilitated the diagnosis and treatment of GC. However, many challenges remain. Expert commentary: To combat GC, sufficient funding is important. More attention should be paid on early diagnosis and the discovery of novel efficient biomarkers and the development of biomarker-based or targeted therapeutics in GC.

Gastric adenocarcinoma

Gastric cancers, with gastric adenocarcinoma (GAC) as the most common histological type, impose a considerable global health burden. Although the screening strategies for early detection have been shown to be successful in Japan and South Korea, they are either not implemented or not feasible in most of the world, leading to late diagnosis in most patients. Helicobacter pylori infection contributes to the development of many endemic GACs, and pre-emptive eradication or early treatment of this bacterial infection might provide effective primary prevention. GACs are phenotypically and genotypically heterogeneous. Localized (clinical stage I) GAC is best treated either endoscopically or with limited surgical resection, but clinical stage II or stage III tumours require multidisciplinary adjunctive approaches in addition to surgery. Although GAC is highly treatable in its early stages, advanced (clinical stage IV) GAC has a median survival of just ∼9-10 months. However, detailed molecular and immune profiling of GAC is yielding promise; early studies with immune checkpoint inhibitors suggest that GAC is amenable to immune modulation. Molecular studies have yielded a vast quantity of new information for potential exploitation. Nevertheless, advances against GACs have lagged compared with other tumours of similar incidence, and more research is necessary to overcome the obstacles to prolong survival.

Helicobacter pylori genotypes determine risk of non-cardia gastric cancer and intestinal- or diffuse-type GC in Ardabil: A very high-risk area in Northwestern Iran

Frequency of the Helicobacter pylori vacA gene polymorphism and its association with gastric cancer (GC) was assessed in Ardabil, a very high-risk area in Northwestern Iran. We determined the presence of the H. pylori 16S rDNA gene and the vacA s-, m-, i-, and d-region genotypes in DNA from fresh gastric biopsies. Patients with GC were classified based on both the anatomic site and the histopathologic type of tumor Of 135 patients, including 57 with non-atrophic gastritis (NAG) and 78 with GC, 103 were infected by H. pylori. The vacA i1 and d1 genotypes were significantly linked to an increased risk of GC, where both cardia (CGC) and non-cardia GC (NCGC) patients were entered into the analysis. The adjusted OR was 9.59 for i1 and 4.39 for d1. Furthermore, i1 was significantly linked to an increased risk of the intestinal-type adenocarcinoma (OR = 14.04) and d1 to the risk of the diffuse-type adenocarcinoma (OR = 7.71). The presence of the m1-type of vacA in combination with i1 or d1 further increased the risk of GC. When the analysis was restricted to NCGC, the adjusted OR for i1 and d1, was 37.52 and 7.17, respectively. No significant association was found between genotypes and the risk of GC in the cardia site of the stomach. It is proposed that the new types of H. pylori vacA, i1 and d1, might be important determinants of NCGC risk in Ardabil. The m1, not independently, but in combination might further define the risk of GC. i1and d1 might also predict the risk of the intestinal- and diffuse-type adenocarcinomas, respectively.

Risk of gastric cancer in Helicobacter pylori infection in a 15-year follow-up

OBJECTIVE

We investigated the risk of gastric cancer among men with Helicobacter pylori (H. pylori) infection or atrophic gastritis (AG) in a 15-year follow-up.

MATERIALS AND METHODS

Study population consists of 12,016 men aged 50-65 years at the beginning of the follow-up in 1994-1996. Serum levels of pepsinogen I (SPGI) and antibodies (IgG) to H. pylori (HpAb) were assayed from serums collected in 1994-1996. Incidence of gastric cancer in the study population was assessed in follow-up from 1994 to 2011 by data from the nationwide cancer registry. Based on SPGI and HpAb values, standardized incidence ratios (SIRs) of gastric cancer were calculated in three subgroups, that is, in those with a healthy stomach, those with H. pylori infection but without AG and those with AG. Risk ratios (RR) of gastric cancer were calculated using SIR of subgroups.

RESULTS

During 15 years, seven gastric cancers appeared per 79,928 person years among men with healthy stomachs, 50 cancers per 92,533 person years in men with H. pylori infection but without AG, and 8 per 8658 person years in men with AG. Risk ratio (RR) of stomach cancer in men with H. pylori infection was 5.8 (95%CI: 2.7-15.3) compared to men with healthy stomachs, and 9.1 (95%CI: 2.9-30.0) in men with AG. There were no differences in cancer risk between cardia and distal stomach.

CONCLUSIONS

Risk of gastric cancer is low in men with healthy stomachs. It is significantly increased in those with H. pylori infection and more in those with AG.

Expression of CDX2 in gastric cardia adenocarcinoma and its correlation with H. pylori and cell proliferation

BACKGROUND

Gastric cardia cancer (GCC) is located in the distal stomach, and strongly correlates with atrophic gastritis and Helicobacter pylori (H.pylori) infection. Caudal-related homeobox transcription factor 2 (CDX2) is homeobox gene encoding an intestine-specific transcription factor usually expressed in the intestinal epithelium cells. However, in several recent published papers, CDX2 was found to be aberrantly expressed in gastric, thyroid and ovarian cancer.

RESULTS

Higher expression of CDX2 was found in GCC tissues in comparison with non-malignant cardia mucosa (p<0.05). Moreover, immunohistochemical analysis demonstrated that CDX2 expression correlated with lymphatic metastasis. In addition, we found that CDX2 expression progressively increased with the level of H. pylori infection (p<0.05), and also correlated with cell proliferation, based on Ki67 staining.

METHODS

To investigate the relationship between CDX2, cell proliferation and H. pylori infection, we detected CDX2, Ki62 and H.pylori expression in 83 non-malignant gastric cardia mucosacases and 60 GCC specimens in the Chaoshan area, a high-risk region for esophageal and gastric cardia cancer.

CONCLUSION

These findings provide pathological evidence that H. pylori infectionis a driving force of gastric cardia carcinogenesis by upregulating CDX2 and inducing inflammation. These results provide new pathological evidence that H. pylori infection induces GCC tumorigenesis.

The Gastric Mucosa from Patients Infected with CagA+ or VacA+ Helicobacter pylori Has a Lower Level of Dual Oxidase-2 Expression than Uninfected or Infected with CagA-/VacA- H. pylori

BACKGROUND

Helicobacter pylori (H. pylori) is a well-recognized gastroduodenal pathogen and class I carcinogen. Dual oxidase-2 (DUOX2), a member of NADPH oxidase family, has several critical physiological functions, including thyroid hormone biosynthesis and host mucosal defense.

AIM

To investigate the effect of H. pylori infection on DUOX2 gene expression in human stomach.

MATERIALS AND METHODS

The biopsies were obtained from patients who underwent endoscopic diagnosis. The patient serum was assayed for two virulence factors of H. pylori, CagA IgG and VacA. The inflammation in gastric mucosa was analyzed with histology. Real-time quantitative PCR was used to detect the expression of three members of NADPH oxidase, NOX1, NOX2, and DUOX2, as well as lactoperoxidase (LPO) in the gastric mucosa. NOX2, DUOX2, and myeloperoxidase (MPO) protein levels were quantified by Western blots or immunohistochemistry.

RESULTS

The H. pylori-infected gastric mucosa had more severe inflammation than uninfected samples. However, the expression of DUOX2 mRNA and protein was lower in gastric mucosa of patients with H. pylori infection compared to the uninfected. Among the H. pylori-infected patients, those having CagA IgG or VacA in the serum had lower DUOX2 expression levels than those infected with H. pylori without either virulence factor. The NOX2 and MPO levels were higher in those patients infected with H. pylori irrespective of the virulence factors than those uninfected patients. NOX1 and LPO mRNA were undetectable in the gastric mucosa.

CONCLUSION

CagA+ or VacA+ H. pylori in the stomach of patients may suppress DUOX2 expression to promote its own survival. Increased NOX2 could not eliminate H. pylori infection.

Two distinct etiologies of gastric cardia adenocarcinoma: interactions among pH, Helicobacter pylori, and bile acids

Gastric cancer can be classified as cardia and non-cardia subtypes according to the anatomic site. Although the gastric cancer incidence has decreased steadily in several countries over the past 50 years, the incidence of cardia cancers and esophageal adenocarcinoma (EAC) continue to increase. The etiological factors involved in the development of both cardia cancers and EACs are associated with high animal fat intake, which causes severe obesity. Central obesity plays roles in cardiac-type mucosa lengthening and partial hiatus hernia development. There are two distinct etiologies of cardia cancer subtypes: one associated with gastroesophageal reflux (GER), which predominantly occurs in patients without Helicobacter pylori (H. pylori) infection and resembles EAC, and the other associated with H. pylori atrophic gastritis, which resembles non-cardia cancer. The former can be developed in the environment of high volume duodenal content reflux, including bile acids and a higher acid production in H. pylori-negative patients. N-nitroso compounds, which are generated from the refluxate that includes a large volume of bile acids and are stabilized in the stomach (which has high levels of gastric acid), play a pivotal role in this carcinogenesis. The latter can be associated with the changing colonization of H. pylori from the distal to the proximal stomach with atrophic gastritis because a high concentration of soluble bile acids in an environment of low acid production is likely to act as a bactericide or chemorepellent for H. pylori in the distal stomach. The manuscript introduces new insights in causative factors of adenocarcinoma of the cardia about the role of bile acids in gastro-esophageal refluxate based upon robust evidences supporting interactions among pH, H. pylori, and bile acids.

Prospective study of Helicobacter pylori antigens and gastric noncardia cancer risk in the nutrition intervention trial cohort

Helicobacter pylori (H. pylori) infection is the strongest known risk factor for gastric noncardia adenocarcinoma (GNCA). We used multiplex serology to determine whether seropositivity to 15 H. pylori proteins is associated with the subsequent development of noncardia gastric cancer in Linxian, China. We included 448 GNCA cases and 1242 controls from two time points within the Linxian General Population Nutrition Intervention Trial, Linxian. H. pylori multiplex seropositivity was defined as positivity to ≥4 of the 15 included antigens. Odds ratios (ORs) and 95% confidence intervals (CIs) were adjusted for major GNCA risk factors. In addition, we undertook a meta-analysis combining H. pylori multiplex serology data from both time points. H. pylori multiplex seropositivity was associated with a significant increase in risk of GNCA at one time point (1985; OR: 3.44, 95% CI: 1.91, 6.19) and this association remained significant following adjustment for H. pylori or CagA ELISA seropositivity (OR: 2.92, 95% CI: 1.56, 5.47). Combining data from both time points in a meta-analysis H. pylori multiplex seropositivity was associated with an increased risk of GNCA, as were six individual antigens: GroEL, HP0305, CagA, VacA, HcpC and Omp. CagM was inversely associated with risk of GNCA. We identified six individual antigens that confer an increase in risk of GNCA within this population of high H. pylori seroprevalence, as well as a single antigen that may be inversely associated with GNCA risk. We further determined that the H. pylori multiplex assay provides additional information to the conventional ELISA methods on risk of GNCA.

Association between oral leukoplakia and upper gastrointestinal cancers: a 28-year follow-up study in the Linxian General Population Trial

BACKGROUND

Oral leukoplakia is a precancerous disorder that is common among residents in Linxian. However, the associations between oral leukoplakia and upper gastrointestinal cancers have not been reported. We investigated the relationships between oral leukoplakia and upper gastrointestinal cancers in the Linxian General Population Trial cohort.

METHODS

The Linxian General Population Trial cohort, with 29,584 healthy adults enrolled in 1985 and followed through the end of 2012. With collected baseline data, hazard ratios (HR) and 95% confidence intervals (95% CI) for developing upper gastrointestinal cancers were estimated using Cox proportional hazard models.

RESULTS

During 28 years of follow-up, we confirmed a total of 2924 incident esophageal squamous cell carcinoma (ESCC) cases, 1644 gastric cardia cancers and 590 gastric non-cardia cancers. Overall, participants with oral leukoplakia had significantly higher risk of developing ESCC (HR=1.18, 95% CI: 1.08, 1.29). Among individuals ⩽52 years old at baseline, oral leukoplakia was associated with elevated risk of ESCC (HR=1.31, 95%CI: 1.15, 1.49). No significant associations were observed for gastric cardia or non-cardia cancers in either all subjects or subgroups.

CONCLUSIONS

Oral leukoplakia was associated with increased risk of ESCC, particularly in younger population. Future studies are needed to confirm these findings.

Helicobacter pylori infection and gastric cardia cancer in Chaoshan region

Helicobacter pylori (H. pylori) infection represents the most important risk factor for gastric cancer, while its association with gastric cardia cancer (GCC) has not been recognized yet. In this current study, we aim to investigate the status of H. pylori infection in the gastric cardia tissue samples from high-risk populations in Chaoshan littoral region, and the relationship between H. pylori infection and chronic inflammation as well as the proliferative activity of the gastric cardia epithelial cells. A total of 706 gastric cardia biopsy specimens were obtained from 372 GCC cases and 334 tumor-free controls in Chaoshan littoral, a high-risk region for esophageal and gastric cardia cancer. Immunohistochemistry and Giemsa staining were employed for the verification of H. pylori infection. H. pylori infection rate was significantly higher in GCC (81.5%, P < 0.01) and gastric carditis (80.1%, P < 0.01) in comparison with that in the healthy group (34.8%). A significant higher prevalence of chronic inflammation was found in H. pylori+ samples (96.9%) than that in H. pylori- specimens (80.5%) (P < 0.01). To explore the possible role of H. pylori infection-related chronic inflammation in the GCC, we found that the expression of Ki-67 was progressively increased in tissues with chronic inflammation degrees from normal to severe inflammation (P < 0.01). Collectively, these results suggest that persistent H. pylori infection and the related chronic inflammation may contribute to the high incidence of GCC in Chaoshan littoral.

Serum Helicobacter pylori CagA antibody may not be used as a tumor marker for diagnosing gastric cancer in east Asian countries

Gastric cancer (GC) is a highly malignant cancer with increasing incidence and mortality worldwide. Serum Helicobacter pylori CagA antibody has been widely reported to play an important role in diagnosing GC. However, published data on this subject are inconclusive. Therefore, we performed a meta-analysis to evaluate the sensitivity and specificity of serum H. pylori CagA antibody in the diagnosis of GC. We conducted a comprehensive search to identify eligible related studies, in which the pooled sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC) curves could be determined. A total of 12 studies including 1,524 cases and 3,324 controls who fulfilled all of the inclusion criteria were included for analysis. The summary estimates for serum H. pylori CagA antibody in the diagnosis of GC in these studies were pooled sensitivity 0.71 (95 % CI 0.69-0.73), specificity 0.40 (95 % CI 0.39-0.42), DOR 2.11 (95 % CI 1.55-2.8), and the area under the curve was 0.636. Our meta-analysis showed that serum H. pylori CagA antibody should not be used for detecting GC.

Helicobacter pylori eradication for preventing gastric cancer

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric cancer (GC) development, which is one of the most challenging malignant diseases worldwide with limited treatments. In the multistep pathogenesis of GC, H. pylori infection slowly induces chronic active gastritis, which progresses through the premalignant stages of atrophic gastritis, intestinal metaplasia, and dysplasia, and then finally to GC. Although eradication of H. pylori is a reasonable approach for the prevention of GC, there have been some contradictory reports, with only some long-term follow-up data showing efficacy of this approach. The inconsistencies are likely due to the insufficient number of participants, relatively short follow-up periods, poor quality of study designs, and the degree and extent of preneoplastic changes at the time of H. pylori eradication. This review analyzes recent high-quality studies to resolve the discrepancies regarding the eradication of H. pylori for GC prevention. The relationship between H. pylori eradication and GC/precancerous lesions/metachronous GC is examined, and the cost-effectiveness of this strategy in the prevention of GC is assessed. Although it is assumed that eradication of H. pylori has the potential to prevent GC, the feasibility and appropriate timing of this strategy for cancer prevention remain to be determined. As a result, additional well-designed trials with longer follow-up periods are needed to clarify this issue.

Evaluation of routine biopsies in endoscopic screening for esophagogastric junction cancer

AIM: To explore whether routine biopsies at the high incidence spot of esophagogastric junction (EGJ) cancer are justified in endoscopic screening.

METHODS: This was a multicenter population-based study conducted in eight high-risk areas in China. A total of 37396 participants underwent endoscopic examination. Biopsies were obtained from visible mucosal abnormalities or from normal-appearing mucosa at the high incidence spot of esophagogastric junction cancer when no abnormality was detected. Specimens showing high-grade intraepithelial neoplasia (HIN) or higher grade lesions were deemed as pathologically “positive”. The ratios of positive pathologic diagnosis between participants with abnormal and normal-appearing mucosa were compared using the Pearson χ² test. Odds ratios and 95% confidence intervals, adjusted for potential confounders, were calculated using logistic regression.

RESULTS: A total of 37520 individuals participated in this study and 37396 (99.7%) participants had full information and were suitable for analysis. During endoscopic examinations, 9.11% (3405/37396) participants were found to have visible mucosal lesions. Of the participants who had normal-appearing mucosa at the EGJ, only 0.28% (94/33991) were diagnosed with HIN or higher grade lesions, whereas 6.05% (206/3405) of participants with abnormalities at the EGJ had a positive pathologic result. After controlling for other variables, visible abnormal mucosa detected under endoscopy strongly predicted a positive pathologic result (OR = 32.51, 95%CI: 23.96-44.09). The proportion of participants with “positive” pathologic diagnoses increased as the total number of endoscopic examinations performed by the doctors increased (< 5000 cases vs 5000-10000 cases vs > 10000 cases, Z = -2.7207, P = 0.0065, Cochran Armiger trend test). The same trend was found between the proportion of participants with positive pathologic diagnoses and the total number of years the doctors performed endoscopy (< 5 years vs 5-10 years vs > 10 years, Z = -10.3222, P < 0.001, Cochran Armiger trend test).

CONCLUSION: Additional routine biopsies from the high incidence spot of EGJ cancer are of limited value and are unjustified.

Diverging trends in the incidence of reflux-related and Helicobacter pylori-related gastric cardia cancer

GOALS

To describe historical incidence trends of 2 subtypes of gastric cardia cancer.

BACKGROUND

The incidence of gastric cardia cancer has increased in western countries. Prior studies have treated cardia cancer as a single entity, but recent data suggest that there are 2 distinct subtypes: reflux-related and Helicobacter pylori-related.

STUDY

We conducted a population-based study using Connecticut Tumor Registry data from 1955 to 2007. Age-adjusted incidence rates (per 100,000 person-years) were calculated for gastric cancer, as a whole and by anatomic subsite, and for esophageal adenocarcinoma. Cardia and noncardia cancer incidence rates were further adjusted to account for cases with unspecified subsite. Mathematical formulas were derived to calculate incidence rates for reflux-related and H. pylori-related cardia cancer.

RESULTS

The adjusted incidence of cardia cancer was 4.0 per 100,000 in 1955 to 1959, decreased to 2.4 per 100,000 in 1965 to 1969 before increasing to 3.4 per 100,000 by 2003 to 2007. The incidence of H. pylori-related cardia cancer decreased from 3.7 to 1.0 per 100,000 over the study period, whereas reflux-related cardia cancer increased progressively from 0.3 to 2.4 per 100,000. The curves for reflux-related cardia cancer and esophageal adenocarcinoma closely mirrored each other, and their combined incidence increased from 0.5 per 100,000 in 1955 to 1959 to 5.6 per 100,000 in 2003 to 2007.

CONCLUSIONS

The incidence of reflux-related cardia cancer has steadily increased, whereas H. pylori-related cardia cancer has declined progressively since the mid-20th century. Trends in reflux-related cardia cancer and esophageal adenocarcinoma incidence are very similar, suggesting that these 2 cancers share a similar etiology and pathophysiological process.

Involvement of Aquaporin 3 in Helicobacter pylori-related gastric diseases

Background

Gastric cancer is one of the most common and lethal malignant cancers worldwide, and numerous epidemiological studies have demonstrated that Helicobacter pylori (H. pylori) infection plays a key role in the development of gastric carcinomas. Our previous studies showed that aquaporin 3 (AQP3) is overexpressed in gastric carcinoma and promotes the migration and proliferation of human gastric carcinoma cells, suggesting that AQP3 may be a potentially important determinant of gastric carcinoma. However, the role of AQP3 in H. pylori carcinogenesis is unknown.

Methods

The AQP3 protein and H. pylori were detected in human gastric tissues by immunohistochemistry and modified Giemsa staining respectively. AQP3 knockdown was obtained by small interfering (si) RNA. Western blot assays and RT-PCR were used to evaluate the change of AQP3 in the human gastric cancer AGS and SGC7901 cell lines after co-culture with H. pylori. Sprague Dawley rats were orally inoculated with H. pylori to establish a rat model colonized by H. pylori.

Results

The present study found that AQP3 expression correlated with H. pylori infection status in gastric cancer tissues and corresponding normal mucosa, and H. pylori co-culture upregulated AQP3 expression in human gastric adenocarcinoma cells in vitro via the extracellular signal-regulated kinase signaling pathway. H. pylori infection also increased AQP3 expression in gastric mucosa colonized by H. pylori in a Sprague Dawley rat model.

Conclusions

These findings provide further information to understand the mechanism of H. pylori carcinogenesis and a potential strategy for the treatment of H. pylori-associated gastric carcinoma.

Prevalence and clinicopathologic characteristics of gastric cardia cancer in South Korea

BACKGROUND AND AIM

Western reports have suggested that the prevalence of gastric cardia cancer (GCC) has been increasing, and indicated some differences between GCC and gastric noncardia cancer (GNCC). However, few studies have been conducted in Asia. The aims of this study were to estimate the prevalence of GCC and to evaluate differences of clinicopathologic characteristics between GCC and GNCC in South Korea.

METHODS

This study was single-center case-control study. A total of 829 patients with gastric cancer and 270 controls were enrolled between 2003 and 2011. Baseline characteristics, Helicobacter pylori (H. pylori) infection status, and histologic characteristics were compared among three groups (GCC, GNCC, and control).

RESULTS

Sixty cases (7.2%) of gastric cancer were located in cardia. Multivariate analysis showed that male odds ratio (OR, 5.72; 95% CI, 1.72-19.07; p = .005) and cigarette smoking (OR, 5.38; 95% CI, 1.39-20.90; p = .015) were risk factors of GCC in comparison with control group, but H. pylori infection rate was not significant. In the case of GNCC, cigarette smoking (OR, 3.87; 95% CI, 1.81-8.29; p < .001), past alcohol intake (OR, 2.82; 95% CI, 1.28-6.20; p = .010), intestinal metaplasia (OR, 3.22; 95% CI, 2.00-5.17; p < .001), and H. pylori infection (OR, 3.06; 95% CI, 1.90-4.93; p < .001) were risk factors of GNCC. Gastroesophageal reflux disease symptoms were higher in the GNCC (21.2%) than control group (13.5%) (p = .008). However, in the case of GCC, they were similar between the GCC (12.7%) and control group (p = .872). According to multivariate analysis, history of H. pylori eradication (OR, 0.34; 95% CI, 0.19-0.61; p < .001) was associated with a protective effect on GNCC. GCC showed higher depth of invasion (p = .038) and frequent distant metastasis (p = .012) than GNCC.

CONCLUSION

In this referral center based study, the prevalence of GCC was 7.2% in South Korea. Risk factors and clinicopathologic characteristics for GCC and GNCC were different, supporting that the pathophysiology is different in the development of GCC and GNCC.

Helicobacter pylori seropositivity and risk of lung cancer

Lung cancer is the leading cause of cancer mortality worldwide. Helicobacter pylori (H. pylori) is a risk factor for distal stomach cancer, and a few small studies have suggested that H. pylori may be a potential risk factor for lung cancer. To test this hypothesis, we conducted a study of 350 lung adenocarcinoma cases, 350 squamous cell carcinoma cases, and 700 controls nested within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC) cohort of male Finnish smokers. Controls were one-to-one matched by age and date of baseline serum draw. Using enzyme-linked immunosorbent assays to detect immunoglobulin G antibodies against H. pylori whole-cell and cytotoxin-associated gene (CagA) antigens, we calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) for associations between H. pylori seropositivity and lung cancer risk using conditional logistic regression. H. pylori seropositivity was detected in 79.7% of cases and 78.5% of controls. After adjusting for pack-years and cigarettes smoked per day, H. pylori seropositivity was not associated with either adenocarcinoma (OR: 1.1, 95% CI: 0.75–1.6) or squamous cell carcinoma (OR: 1.1, 95% CI: 0.77–1.7). Results were similar for CagA-negative and CagA-positive H. pylori seropositivity. Despite earlier small studies suggesting that H. pylori may contribute to lung carcinogenesis, H. pylori seropositivity does not appear to be associated with lung cancer.

Comparative epidemiology of gastric cancer between Japan and China

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

The diagnosis and management of gastric cancer: expert discussion and recommendations from the 12th ESMO/World Congress on Gastrointestinal Cancer, Barcelona, 2010

Well-recognized experts in the field of gastric cancer discussed during the 12th European Society Medical Oncology (ESMO)/World Congress Gastrointestinal Cancer (WCGIC) in Barcelona many important and controversial topics on the diagnosis and management of patients with gastric cancer. This article summarizes the recommendations and expert opinion on gastric cancer. It discusses and reflects on the regional differences in the incidence and care of gastric cancer, the definition of gastro-esophageal junction and its implication for treatment strategies and presents the latest recommendations in the staging and treatment of primary and metastatic gastric cancer. Recognition is given to the need for larger and well-designed clinical trials to answer many open questions.

Serum Helicobacter pylori CagA antibody as a biomarker for gastric cancer in east-Asian countries

AIMS

In east-Asian countries, while almost all Helicobacter pylori strains possess the cytotokine-associated gene A (CagA) gene, serum CagA antibody is not detected in some infected subjects. We aimed to clarify the association between anti-CagA antibody and gastric cancer in east-Asian countries.

MATERIALS AND METHODS

We performed a meta-analysis of case-control studies with age- and sex-matched controls, which provided raw data in east-Asian countries.

RESULTS

Ten studies with a total of 4325 patients were identified in the search. Some reports from Japan, Korea and China showed a positive association between the presence of anti-CagA antibody and gastric cancer; however, the results differed in their various backgrounds. The disparate findings appeared to result from the use of different methods or from variations in the antigens used to detect the anti-CagA antibody. CagA seropositivity was associated with an increased risk of developing gastric cancer.

CONCLUSION

Anti-CagA antibody can be used as a biomarker for gastric cancer even in east-Asian countries.

Helicobacter pylori infection and gastric cardia cancer: systematic review and meta-analysis

OBJECTIVE

Helicobacter pylori infection is the most important risk factor for gastric cancer, but no association with cardia cancer has been recognized. However, a heterogeneous distribution of etiologically distinct types of cardia cancer may contribute to explain conflicting findings between studies in high- and low-risk settings. We aimed to quantify the association between H. pylori infection and gastric cardia cancer through meta-analysis, and to provide an explanation for the expected heterogeneity of results.

METHODS

We systematically reviewed published studies addressing the association between H. pylori infection and gastric cardia cancer (up to June 2009), and extracted relative risk (RR) estimates for the association with cardia and non-cardia cancers. Summary RR estimates and 95% confidence intervals (95% CI) were computed using random-effects models. Subgroup analyses were conducted, namely according to gastric cancer risk settings.

RESULTS

Thirty-four articles were considered for meta-analysis. For cardia cancer, summary RR was 1.08 (95% CI 0.83-1.40; I (2) = 52.8%), higher in high-risk (RR = 1.98; 95% CI 1.38-2.83; I (2) = 18.4%) than in low-risk settings (RR = 0.78; 95% CI 0.63-0.97; I (2) = 11.6%). For non-cardia cancer, RR estimates were similar in high- (RR = 3.02; 95% CI 1.92-4.74; I (2) = 90.7%) and low-risk settings (RR = 2.56; 95% CI 1.99-3.29; I (2) = 46.6%). These observations were consistent across different inclusion criteria and when accounting for the virulence of the infecting strains.

CONCLUSIONS

In high-risk settings, a positive association between H. pylori infection and gastric cancer was observed both for cardia and non-cardia cancers. The results support the hypothesis of a heterogeneous distribution of etiologically distinct types of cardia cancer.

Helicobacter pylori Seropositivity Is Associated with Gastric Cancer Regardless of Tumor Subtype in Korea

BACKGROUND/AIMS

To evaluate the association between Helicobacter pylori (H. pylori) infection and gastric cancer (GC) according to tumor subtype in Korea.

METHODS

H. pylori status was determined serologically using the enzyme-linked immunosorbent assay. In total, 2,819 patients with GC and 562 healthy controls were studied. A logistic regression method was used after adjusting for possible confounders.

RESULTS

The prevalence of H. pylori infection was significantly higher in the GC patients (84.7%) than in the controls (66.7%) (odds ratio [OR], 3.13; 95% confidence interval [CI], 2.46-3.97). The adjusted OR was significantly higher in H. pylori-infected patients aged <60 years (OR, 4.69; 95% CI, 3.44-6.38) than in those aged ≥60 years (OR, 1.48; 95% CI, 0.88-2.46; p<0.001). Subgroup analyses revealed no differences in seroprevalence between early gastric cancer (84.8%; OR, 3.01; 95% CI, 2.27-4.01) and advanced gastric cancer (84.6%; OR, 2.94; 95% CI, 2.24-3.85), cardia cancer (83.8%; OR, 2.98; 95% CI, 2.16-4.02) and noncardia cancer (84.8%; OR, 3.17; 95% CI, 2.48-4.04), and differentiated carcinoma (82.7%; OR, 2.99; 95% CI, 2.21-4.04) and undifferentiated carcinoma (86.8%; OR, 3.05; 95% CI, 2.32-4.00).

CONCLUSIONS

The seroprevalence of H. pylori was higher in GC patients than in healthy controls, especially in younger patients. H. pylori infection is associated with GC, regardless of the tumor location, stage, or differentiation.

Helicobacter pylori infection may be implicated in the topography and geographic variation of upper gastrointestinal cancers in the Taihang Mountain high-risk region in northern China

BACKGROUNDS

Helicobacter pylori infection is prevalent in China. Chronic infection of the bacterial not only causes distal stomach cancer, but also confers risk to gastric cardia adenocarcinoma. Because H. pylori infection is inversely associated with esophageal adenocarcinoma, globally the infection rate is significantly correlated with the ratio of squamous carcinoma to adenocarcinoma of the esophagus. These agree with the topography of upper gastrointestinal cancer observed in the Taihang Mountain high-risk region where both gastric cardia and non-cardia adenocarcinoma coincide with esophageal squamous cancer, but with almost no distal esophageal adenocarcinoma. Moreover, as altitude increases from plain to mountains, we observed progressively increasing incidence rates of gastric adenocarcinomas in recent years in the region. Because H. pylori infection is a definite carcinogen to gastric adenocarcinoma and is more prevalent in the mountain than in plain areas due to undeveloped living conditions, the observation gives the impression as though H. pylori infection is implicated.

AIMS

This article aims to note the role of H. pylori infection in upper gastrointestinal cancer in the Taihang Mountain high-risk region in northern China.

MATERIALS AND METHODS

First the unique topography and geographic variation of upper gastrointestinal cancer in the region is described to indicate a possible role of H. pylori infection, then we review studies on prevalence of H. pylori infection in the high-risk region and describe difference in socioeconomic development and water hygiene between the plains and the mountains as related to the prevalence of H. pylori infection.

RESULTS

  Coincidence of gastric cancer in the region and a progressively increasing rate of the cancer from the plain towards the mountains indicate H. pylori infection may be implicated in upper gastrointestinal cancer.

CONCLUSION

International collaboration is needed to study H. pylori and upper gastrointestinal cancer in the region when rapid industrialization is just beginning.

Serum pepsinogens and Helicobacter pylori in relation to the risk of esophageal squamous cell carcinoma in the alpha-tocopherol, beta-carotene cancer prevention study

BACKGROUND

Helicobacter pylori can induce gastric atrophy in humans, which in turn increases gastric cancer risk. Whether H. pylori and gastric atrophy also affect the risk of esophageal squamous cell carcinoma (ESCC), however, remains unresolved.

METHODS

We performed a nested case-control study within the prospective Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study to assess these relationships. The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study is composed of 29,133 Finnish male smokers, ages 50 to 69 years, who were recruited during 1985-1988. Using baseline sera, we assessed H. pylori status (via immunoglobulin G antibodies against whole-cell and CagA antigens) and gastric atrophy status [via the biomarkers pepsinogen I (PGI) and pepsinogen II (PGII)] in 79 ESCC cases and 94 controls. Logistic regression with adjustment for age, date of blood draw, education, cigarette smoking, alcohol, body mass index, and fruit and vegetable intake was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Gastric atrophy (PGI/PGII <4) was associated with ESCC (OR, 4.58; 95% CI, 2.00-10.48). There was no evidence for an association between H. pylori and ESCC (OR, 0.94; 95% CI, 0.40-2.24).

CONCLUSIONS

These results could be explained by misclassification of H. pylori status due to serologic amnesia, ESCC risk being dependent on the functional consequences or interactions of H. pylori rather than the infection per se, gastric atrophy having a different histogenesis in ESCC without being primarily dependent on H. pylori acquisition, or a lack of statistical power to detect an effect.

IMPACT

Validation of these results may warrant mechanistic studies to determine the route of association between gastric atrophy and ESCC.

Molecular identification of Helicobacter DNA in human gastric adenocarcinoma tissues using Helicobacter species-specific 16S rRNA PCR amplification and pyrosequencing analysis

Helicobacter pylori (H. pylori) is a microaerophilic gram-negative bacterium known to be associated with chronic gastritis, peptic ulcer and gastric adenocarcinoma. In the present study, the presence of Helicobacter DNA was investigated using a Helicobacter species-specific 16S rRNA PCR amplification and pyrosequencing analysis in 51 resected gastric adenocarcinomas. DNA was extracted from paraffin-embedded tissues of resected gastric adenocarcinomas. PCR primers were designed to amplify the 133-bp PCR fragment in highly conserved regions of the 16S rRNA gene. The sequence of the PCR products was analyzed using a PSQ 96 system with SQA software. The pyrosequencing analysis of 16S rRNA showed that H. pylori was present in 47 (92.2%) of the 51 gastric adenocarcinomas. In the 4 H. pylori-negative cases, Helicobacter cinaedi (2 cases), Helicobacter mustelae (1 case) and Campylobacter hyointestinalis (1 case) were detected. Pyrosequencing technology was useful in the identification and differentiation of H. pylori from other species by analyzing the gene encoding 16S rRNA. Gastric adenocarcinoma tissues contain bacteria, and the majority are H. pylori. Helicobacter cinaedi, Helicobacter mustelae and Campylobacter hyointestinalis rarely occur. The roles of these organisms in the pathogenesis of gastric adenocarcinoma remain unclear.

Association between Helicobacter pylori seropositivity and digestive tract cancers

AIM: To explore the role of Helicobacter pylori (H pylori) infection on the risk of digestive tract cancers.

METHODS: In total, 199 oral squamous-cell carcinoma (SCC), 317 esophageal SCC, 196 gastric cardia and non-cardia adenocarcinoma and 240 colon adenocarcinoma patients were recruited for serum tests of H pylori infection. Two hospital- and one community-based control groups were used for the comparisons. H pylori seropositivity was determined by an enzyme linked immunosorbent assay method against H pylori IgG.

RESULTS: Presence of H pylori infection was significantly inversely associated with esophageal SCC [adjusted odds ratio (AOR): 0.315-0.472, all P-value < 0.05] but positively associated with gastric adenocarcinoma (both cardia and non-cardia) (AOR: 1.636-3.060, all P-value < 0.05) in comparison to the three control groups. Similar results were not found in cancers of the oral cavity and colon.

CONCLUSION: Our findings support the finding that H pylori seropositivity is inversely associated with esophageal SCC risk, but increases the risk of gastric cardia adenocarcinoma.

Etiologic factors of gastric cardiac adenocarcinoma among men in Taiwan

AIM: To elucidate etiologic associations between Helicobacter pylori (H pylori), lifestyle, environmental factors and gastric cardiac adenocarcinoma (GCA) among men.

METHODS: A hospital-based case-control study was conducted in Taiwan from 2000 to 2009. All cases were newly confirmed as primary GCA. Five controls were selected matching with age, sex, and admission date to each case. Participants were informed of potential risk factors with a structured questionnaire by trained interviewers during hospitalization and provided a blood sample for the determination of H pylori infection. Odds ratio (OR) and 95% confidence interval (95% CI) were used to evaluate risk, and a multivariate conditional logistic regression model was performed.

RESULTS: All participants recruited for this study were men, consisting of 41 cases and 205 controls. Results of the univariate analysis showed that significant factors associated with the etiology of GCA included H pylori (OR = 2.69, 95% CI = 1.30-5.53), cigarette smoking (OR = 2.28, 95% CI = 1.05-4.96), working or exercising after meals (OR = 3.26, 95% CI = 1.31-8.11), salted food (OR = 2.51, 95%CI = 1.08-6.11), fresh vegetables (OR = 0.28, 95% CI = 0.09-0.80), fruits (OR = 0.19, 95% CI = 0.04-0.89), and rice as principal food (OR = 0.53, 95% CI = 0.30-0.85). Multivariate conditional logistic regression models indicated that a significantly elevated risk of contracting GCA was associated with working or exercising after meals (OR = 3.18, 95% CI = 1.23-9.36) and H pylori infection (OR = 2.93, 95% CI = 1.42-6.01). In contrast, the consumption of fresh vegetables (OR = 0.22, 95% CI = 0.06-0.83), fruits (OR = 0.28, 95% CI = 0.09-0.79) and rice as principal food (OR = 0.48, 95% CI = 0.24-0.93) remained as significant beneficial factor associated with GCA.

CONCLUSION: Working or exercising after meals and H pylori infection increase the risk of GCA, but higher intakes of rice, fresh vegetables and fruits reduce the risk.

Dietary folate and vitamin B12 intake before diagnosis decreases gastric cancer mortality risk among susceptible MTHFR 677TT carriers

OBJECTIVE

To assess gastric cancer survival in relation to dietary intake of methyl donors and the methylenetetrahydrofolate reductase 677C>T (MTHFR 677C>T) polymorphism.

METHODS

A prospective cohort of 257 incidental, histologically confirmed gastric cancer cases was assembled in January 2004 and followed until June 2006. Patients were recruited from the main oncology and/or gastroenterology units in Mexico City and were queried regarding their sociodemographic information, clinical history, and dietary habits 3 y before the onset of their symptoms. The intake of methyl donors was estimated with a food-frequency questionnaire and the MTHFR 677C>T polymorphisms were determined by polymerase chain reaction/restriction fragment length polymorphism analysis. Cox's multivariate regression models were used to estimate the mortality risk of gastric cancer.

RESULTS

MTHFR 677TT carriers with low folate and vitamin B12 intakes had the lowest survival rate in cases of gastric cancer. High intakes of folate and vitamin B12 before diagnosis was associated with decreased gastric cancer mortality risk in susceptible MTHFR 677TT carriers (mortality risk for folate 0.14, 95% confidence interval 0.04-0.46, P for trend=0.001; mortality risk for vitamin B12 0.23, 95% confidence interval 0.08-0.66, P for trend=0.008).

CONCLUSION

Folate and related B vitamins may be used as an intervention strategy to improve the survival outcome of gastric cancer.

Subsite distribution of gastric cancer in an area of high prevalence--northwest Iran

BACKGROUND

The aim of the present study was to determine subsites of gastric cancer in East Azerbaijan, Iran-a high incidence region for gastric cancer and Helicobacter pylori infection.

METHODS

Data were collected from 2002 through 2007 from patients who sought treatment for gastrointestinal symptoms or signs at a university clinic and subsequently underwent upper gastrointestinal endoscopy.

RESULTS

Cancer was diagnosed and histologically confirmed in 362 patients (352 adenocarcinomas). The mean age of the patients was 64.57 +/- 11.32 (range, 16-94 years) and the male-to-female ratio was 2.8:1. The gastric cardia was involved in 40.3% of patients with gastric adenocarcinoma, while the gastric fundus was involved in 3.7%, the gastric body in 49.1%, and the gastric antrum in 24.1% of patients. Complete evaluation for metastasis was possible in 144 patients; 61 were free of metastasis, and most of these patients underwent surgical therapy. Cardia involvement was not associated with the sex or age of patients.

CONCLUSIONS

Noncardia gastric cancer is still more frequent in East Azerbaijan, which is likely due to the very high prevalence of infection with Helicobacter pylori. The low rate of cancer involving the fundus is a target for further research on the etiology of gastric cancer.

The effect of laparoscopic gastric banding surgery on plasma levels of appetite-control, insulinotropic, and digestive hormones

BACKGROUND

We hypothesized that laparoscopic adjustable gastric banding (LAGB) reduces weight and modulates ghrelin production, but largely spares gastrointestinal endocrine function. To examine this hypothesis, we determined plasma concentrations of appetite-control, insulinotropic, and digestive hormones in relation to LAGB.

METHODS

Twenty-four patients undergoing LAGB were prospectively enrolled. Body mass index (BMI) was measured and blood samples obtained at baseline and 6 and 12 months post-surgery. Plasma concentrations of leptin, acylated and total ghrelin, pancreatic polypeptide (PP), insulin, glucose-dependent insulinotropic peptide (GIP), active glucagon-like peptide-1 (GLP-1), gastrin, and pepsinogens I and II were measured using enzyme-linked immunoassays.

RESULTS

Median percent excess weight loss (%EWL) over 12 months was 45.7% with median BMI decreasing from 43.2 at baseline to 33.8 at 12 months post-surgery (p < 0.001). Median leptin levels decreased from 19.7 ng/ml at baseline to 6.9 ng/ml at 12 months post-surgery (p < 0.001). In contrast, plasma levels of acylated and total ghrelin, PP, insulin, GIP, GLP-1, gastrin, and pepsinogen I did not change in relation to surgery (p > 0.05). Pepsinogen II levels were significantly lower 6 months after LAGB but returned to baseline levels by 12 months.

CONCLUSIONS

LAGB yielded substantial %EWL and a proportional decrease in plasma leptin. Our results support the hypothesis that LAGB works in part by suppressing the rise in ghrelin that normally accompanies weight loss. Unchanged concentrations of insulinotropic and digestive hormones suggest that gastrointestinal endocrine function is largely maintained in the long term.

Asia-Pacific consensus guidelines on gastric cancer prevention

BACKGROUND AND AIM

Gastric cancer is a major health burden in the Asia-Pacific region but consensus on prevention strategies has been lacking. We aimed to critically evaluate strategies for preventing gastric cancer.

METHODS

A multidisciplinary group developed consensus statements using a Delphi approach. Relevant data were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded.

RESULTS

Helicobacter pylori infection is a necessary but not sufficient causal factor for non-cardia gastric adenocarcinoma. A high intake of salt is strongly associated with gastric cancer. Fresh fruits and vegetables are protective but the use of vitamins and other dietary supplements does not prevent gastric cancer. Host-bacterial interaction in H. pylori infection results in different patterns of gastritis and differences in gastric acid secretion which determine disease outcome. A positive family history of gastric cancer is an important risk factor. Low serum pepsinogens reflect gastric atrophy and may be useful as a marker to identify populations at high risk for gastric cancer. H. pylori screening and treatment is a recommended gastric cancer risk reduction strategy in high-risk populations. H. pylori screening and treatment is most effective before atrophic gastritis has developed. It does not exclude the existing practice of gastric cancer surveillance in high-risk populations. In populations at low risk for gastric cancer, H. pylori screening is not recommended. First-line treatment of H. pylori infection should be in accordance with national treatment guidelines.

CONCLUSION

A strategy of H. pylori screening and eradication in high-risk populations will probably reduce gastric cancer incidence, and based on current evidence is recommended by consensus.