Helicobacter pylori in promotion of gastric carcinogenesis

Prevalence of Gastric Precursor Lesions in Countries With Differential Gastric Cancer Burden: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The prevalence of precursor lesions for gastric cancer (GC) and the differential burden between countries of varying GC risk is not well-understood. We conducted a systematic review and meta-analysis to estimate the global prevalence of precursor lesions.

METHODS

We estimated the prevalence of atrophic gastritis (AG), gastric intestinal metaplasia (IM), and dysplasia in regions with low, medium, and high GC incidence. Because IM is an advanced manifestation of AG, we assessed the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. Prevalence was sub-stratified by Helicobacter pylori infection, symptomatology, and period (<2000, 2000-2010, and >2010).

RESULTS

Among the 582 articles that underwent full-text review, 166 studies met inclusion criteria. The global prevalence estimates of AG, IM, and dysplasia were 25.4%, 16.2%, and 2.0%, respectively, on the basis of 126 studies that reported the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. The prevalence of all precursor lesions was higher in high and medium compared with low GC incidence countries (P < .01). Prevalence of AG and IM was significantly higher among H pylori-infected individuals (P < .01) but not statistically different between symptomatic and asymptomatic individuals (P > .17). All precursors demonstrated a secular decrease in prevalence over time.

CONCLUSIONS

Gastric precursor lesions have differences in prevalence in regions with differential GC incidence and are associated with H pylori infection. Because of the substantial prevalence of precursor lesions in both symptomatic and asymptomatic individuals, symptomatic evaluation may not be sufficient to identify individuals at risk. These estimates provide important insights for tailoring GC prevention strategies.

Failure of Helicobacter pylori eradication and age are independent risk factors for recurrent neoplasia after endoscopic resection of early gastric cancer in 283 patients

BACKGROUND

Whether the incidence of metachronous gastric dysplasia and cancer could be decreased by eradication of Helicobacter pylori after endoscopic submucosal dissection (ESD) for early gastric cancer (EGC).

AIM

To compare the incidence of metachronous gastric lesion in the eradicated group and the persistent group. Second end point is to evaluate the risk factors for metachronous gastric lesions after ESD for EGC.

METHODS

In a single centre, between May 2007 and May 2010, the patients who had evidence of H. pylori infection at the time of ESD for EGC were included, and the follow-up data were analysed retrospectively.

RESULTS

We enrolled 283 patients who have shown H. pylori infection at the time of ESD for EGC. Successful eradication was achieved for 214 patients (75.6%) (Eradicated group), and 69 patients (24.4%) showed persistent H. pylori infection (Persistent group). Metachronous gastric lesions developed in 13 (18.8%) in the persistent group and 18 (8.4%) in the eradicated group (P = 0.016). In the ≥60-year-old group, the cumulative incidence of metachronous gastric cancer showed a significant increase (P = 0.012). Cumulative hazard ratio of subsequent gastric metachronous lesions differed between the eradication group and the persistent infection group (OR = 2.322, 95% CI = 1.136-4.744, P = 0.021), and ≥60 age at the time of endoscopic resection (OR = 2.803, 95% CI = 1.207-6.509, P = 0.016).

CONCLUSIONS

Both persistent H. pylori infection and old age (≥60) are independent risk factors for the increased incidence of metachronous gastric cancer.

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia

AIM

To investigate the predictive value of narrow-band imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients.

METHODS

We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings.

RESULTS

We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI: 67-92), a specificity of 96% (95%CI: 93-99), a positive predictive value of 84% (95%CI: 73-96), a negative predictive value of 95% (95%CI: 92-98), and an accuracy of 93% (95%CI: 90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GIM was less than 5% in 7 of the cases. Moreover, in the 6 false positive cases, the histological examination showed the presence of reactive gastropathy (4 cases) or H. pylori active chronic gastritis (2 cases). The semiquantitative correlation between the rate of LBC appearance and the percentage of GIM was 79% (P < 0.01).

CONCLUSION

NBI-ME achieved good sensitivity and specificity in recognising GIM in an unselected population. In routine clinical practice, this technique can reliably target gastric biopsies.

Oxidative stress in inflammation-based gastrointestinal tract diseases: challenges and opportunities

Oxygen free radicals in excessively high amounts are all very reactive chemically and can impose a detrimental influence on living organisms by provoking "oxidative stress" that can damage major cellular constituents. The latter includes the cell membrane, cytoplasmic proteins, and nuclear DNA. Conversely, nitric oxide (NO), superoxide anion, and related reactive oxygen species (ROS) when present in low amounts play an important role as regulatory mediators in signaling processes, through which, paradoxically, many ROS-mediated responses can protect the cells against oxidative stress by induction of "redox homeostasis." Therefore, diseases associated with free radical overproduction are provoked by "blazed ROS productions" far beyond the host's capacity to quench. Free radicals have been implicated in the pathogenesis of diverse gastrointestinal (GI) diseases including gastroesophageal reflux disease (GERD), gastritis, enteritis, colitis and associated cancers as well as pancreatitis and liver cirrhosis. This article provides an overview of the role of oxidative stress in inflammation-based GI tract diseases, including reflux esophagitis, Helicobacter pylori-associated gastritis, non-steroidal anti-inflammatory drug-induced enteritis, ulcerative colitis, and associated colorectal cancer. The challenging issue that ROS can contribute to diverse gastrointestinal dysfunction, or manifest dual roles in cancer promotion or cancer suppression will also be discussed for the opportunity to enhance understanding of inflammation-based GI diseases.

Follow-up of intestinal metaplasia in the stomach: When, how and why

Gastric cancer remains the second most frequent cause of cancer-related mortality in the world. Screening programs in some Asian countries are impractical in the majority of other countries worldwide. Therefore, follow-up of precancerous lesions is advisable for secondary gastric cancer prevention. Intestinal metaplasia (IM) is recognized as a precancerous lesion for gastric cancer, increasing the risk by 6-fold. IM is highly prevalent in the general population, being detected in nearly 1 of every 4 patients undergoing upper endoscopy. The IM prevalence rate is significantly higher in patients with Helicobacter pylori (H. pylori) infection, in first-degree relatives of gastric cancer patients, in smokers and it increases with patient age. IM is the “breaking point” in the gastric carcinogenesis cascade and does not appear to regress following H. pylori eradication, although the cure of infection may slow its progression. Gastric cancer risk is higher in patients with incomplete-type IM, in those with both antral and gastric body involvement, and the risk significantly increases with IM extension over 20% of the gastric mucosa. Scheduled endoscopic control could be cost-effective in IM patients, depending on the yearly incidence of gastric cancer in IM patients, the stage of gastric cancer at diagnosis discovered at surveillance, and the cost of endoscopy. As a pragmatic behavior, yearly endoscopic control would appear justified in all IM patients with at least one of these conditions: (1) IM extension > 20%; (2) the presence of incomplete type IM; (3) first-degree relative of gastric cancer patients; and (4) smokers. In the remaining IM patients, a less intensive (2-3 years) could be proposed.

The effect of age and Helicobacter pylori infection on gastric epithelial cell kinetics

BACKGROUND

Helicobacter pylori infection is a known risk factor for gastric cancer. The aim of the study was to determine the effect of H. pylori and age on gastric epithelial cell kinetics.

METHODS

One hundred and fifty-seven patients (92 men, median age: 58.5 years, range: 18-85) who had undergone upper gastrointestinal endoscopy due to dyspeptic symptoms were enrolled into the study. Six antral biopsy samples were obtained for flow cytometric DNA analysis (expressed as proliferative index [PI], S+G2/M phase), presence of H. pylori (CLO-test, culture and histology), and histopathologic examination.

RESULTS

Eighty-four (53.5%) patients were H. pylori positive and 93.3% of patients had diploid pattern and 6.7% expressed aneuploid pattern. The mean PI was 4.8 ± 0.2 for the whole group studied. PI were 5.14 ± 0.33 and 4.26 ± 0.36 for H. pylori (+) and H. pylori (-) patients respectively (P = 0.017). When age groups were taken into account, PI was found higher in patients over 75 years of age (n = 14, PI = 6.66 ± 1.3) compared to patients under 35 years of age (n = 25, PI = 3.83 ± 0.41, P = 0.014). There was no correlation between histological changes and PI. H. pylori (P = 0.045) and age (P = 0.082) were independent factors for PI.

CONCLUSION

PI of gastric antral mucosa increases in patients with H. pylori infection. Although PI increases by age, H. pylori is the only factor that significantly and independently influences the rate of epithelial cell proliferation.

Determinação histopatológica da presença do helicobacter pylori em câncer gástrico

RACIONAL: A causa do câncer gástrico (CG) é controversa e tem vários fatores envolvidos no seu processo de carcinogênese, incluindo o Helicobacter pylori (Hp) O papel da infecção pelo Hp no CG permanece incerto, com vários estudos controversos. OBJETIVO: Correlacionar a presença da infecção pelo Hp com câncer gástrico, através de exame anatomopatológico convencional do estômago ressecado. MÉTODO: Noventa e um pacientes tratados por ressecção cirúrgica foram revistos. O exame anatomopatológico foi feito em todos os pacientes para determinar a presença de infecção por Hp, metaplasia intestinal (MI) e confirmação do tipo histológico por hematoxilina-eosina. A análise estatística foi realizada através do qui-quadrado e testes de log-rank. RESULTADOS: MI foi observada em 81 tumores (89%). Em geral, a presença de infecção pelo Hp foi observada em 46 casos (50,5%). Não houve associação entre idade e Hp. Nos grupos de pacientes com CG avançado e precoce, a infecção pelo Hp estava presente em 47,7% e 54% dos tumores. A infecção pelo Hp ocorreu em 40 tumores (49%) no grupo de pacientes com MI. Nos com tumores sem MI, Hp estava presente em cinco (50%). Tumores proximais tiveram mais infecção por Hp, quando comparados aos tumores distais. CONCLUSÕES: A taxa de infecção não teve associação significativa com o tipo histológico, sexo, MI ou estágio de desenvolvimento tumoral. Esses resultados podem indicar que a participação da infecção pelo Hp durante o desenvolvimento do CG não pode ser descartada; no entanto, provavelmente não é essencial em todas as fases e o mecanismo do CG pode ser distinto da gastrite crônica e MI. Finalmente, é possível que a associação proposta é mera coincidência e que não há nenhuma influência real das bactérias no processo de carcinogênese.

CagA and VacA Helicobacter pylori antibodies in gastric cancer

BACKGROUND

Infection with different genotypes of virulent Helicobacter pylori strains (cytotoxin-associated gene A [CagA]- and/or vacuolating cytotoxin A [VacA]-positive) can play a role in the development of atrophic gastritis, duodenal ulcer (DU) and gastric cancer (GC).

OBJECTIVE

To determine whether patients with GC and H pylori-negative histological staining had previously been infected with H pylori CagA- and/or VacA-positive virulent strains.

METHODS

Twenty-three GC patients with a mean (+/- SD) age of 68.14+/-9.8 years who tested H pylori-negative on histological staining took part in the study. Three control groups were included. The first group comprised 19 patients with past H pylori infection and DUs eradicated 10 years earlier, with a mean age of 58+/-18.2 years. H pylori-negative status for this group was determined every year with Giemsa staining, and follow-up testing occured 120+/-32 months (mean +/- SD) after therapy. The subsequent control groups included 20 asymptomatic children, with a mean age of 7+/-4.47 years, and with H pylori-negative fecal tests; the final group contained 30 patients without clinical symptoms of H pylori infection, with a mean age of 68+/-11.6 years, who tested H pylori-negative by histological staining.

RESULTS

Prevalence of CagA and VacA seropositivity, respectively was 82.6% and 73.91% in GC patients; 84.2% and 84.2% in H pylori-negative DU patients; 25% and 5% in H pylori-negative children; and 36.6% and 16.6% in the patients without clinical symptoms on histological staining. CagA and VacA antibody positivity was not significantly different between GC patients and patients with DUs that had been eradicated 10 years earlier. Significant positivity was found between the children's group and the H pylori-negative (with past DUs) group (P<0.001). A statistically significant difference was found in age between groups (P<0.03).

CONCLUSIONS

Patients with GC, even when H pylori-negative at the time of the present study, may have been infected by H pylori before the onset of the disease, as confirmed by CagA and VacA seropositivity. These data reinforce the hypothesis that H pylori may be a direct carcinogenic agent of GC.

Systematic review of the prevalence of gastric intestinal metaplasia and its area-level association with smoking

OBJECTIVES

We aimed to show an area-level association between the frequency of intestinal metaplasia (IM) in Helicobacter pylori-infected patients and tobacco consumption.

METHODS

We systematically reviewed the literature to retrieve data on the prevalence of IM in different countries and performed an ecological analysis to quantify the association between the prevalence of IM among infected subjects and smoking, using data on national tobacco availability. Articles evaluating IM in the general population or in dyspeptic patients were identified by a MEDLINE search. We selected one study per country, giving preference to those for which the study design/populations evaluated provided the highest external validity and inter-study comparability of methodology.

RESULTS

This systematic review of published data retrieved information for 29 countries from 5 continents depicting a wide variation in the prevalence of IM among H. pylori-infected subjects in different regions, ranging from 3% in Argentina to 55% in New Zealand. In countries exhibiting a simultaneously high prevalence of infection and low incidence of gastric cancer, IM was also relatively infrequent (Thailand, 6%; India, 8.2%; Nigeria, 11.1%; Gambia, 11.8%; Saudi Arabia, 15.5%; Iran, 15.6%; Egypt, 24.4%). A significant correlation was observed between IM prevalence in infected subjects and tobacco availability (r = 0.45; p = 0.02).

CONCLUSIONS

Our results show that the concept of the African and Asian "enigmas" may be extended to precancerous lesions. Tobacco availability was positively associated with the prevalence of IM among H. pylori-infected subjects at an area level.

Gastrointestinal tract pathology in patients with common variable immunodeficiency (CVID): a clinicopathologic study and review

BACKGROUND

Common variable immunodeficiency (CVID) is characterized by a host of gastrointestinal (GI) lesions that can mimic other conditions.

METHODS

We reviewed clinical documentation and samples from 132 separate GI biopsy or resection sites on 20 CVID patients obtained over a 26-year period, including biopsies from the colon (34), esophagus (19), small intestine (38), and stomach (35), a partial gastrectomy, small bowel resection, colectomy, 2 cholecystectomies, and 1 appendectomy.

RESULTS

There were 13 males and 7 females. Nine patients were children (10 y and younger) and 11 were adults. Age at diagnosis ranged from 6 months to 62 years (median, 35.5 y), and age at biopsy ranged from 10 months to 67 years (median, 38 y). Esophageal samples often showed intraepithelial neutrophils, accompanied by candida. Half of patients' esophageal biopsies had prominent intraepithelial lymphocytosis, one of which also had prominent apoptosis. The stomachs of 67% of patients lacked plasma cells. Most showed lymphoid aggregates. An increase in apoptosis was detected in biopsies from a third. About 20% had a lymphocytic gastritis pattern. Intraepithelial neutrophils were found in a subset, accompanied by various infections [cytomegalovirus (CMV), Helicobacter pylori, and Cryptosporidium]. Granulomas were found in 1 patient. Gastric adenocarcinoma was identified in one patient. There was a paucity of small bowel plasma cells in the majority of patients (68%). The small bowel showed prominent lymphoid aggregates in about half (47%). An increase in apoptosis was detected in specimens from about 20%. Increased intraepithelial lymphocytes (IELs) were found in samples from over half of patients (63%), most of whom (83%) also had villous blunting, mimicking celiac disease. Intraepithelial neutrophils were found in a subset (32%) and correlated with CMV and Cryptosporidium infections. Granulomas were seen in biopsies from 2 patients (11%). One patient had a collagenous enteritis pattern (accompanied by a collagenous colitis pattern). One patient had autoimmune enteritis; biopsies from this patient were initially relatively normal but later displayed prominent crypt apoptosis and loss of goblet cells. In colon samples, a paucity of plasma cells was seen in 10 patients (63%). The colon showed lymphoid aggregates in most patients (81%). Apoptosis was prominent in samples from half of the patients (50%). Biopsies from 6 patients had a lymphocytic colitis pattern (38%) and 2 patients had a collagenous colitis pattern. Intraepithelial neutrophils were found in samples from most patients (88%). Crypt distortion was seen in 6 of these patients (43%), thereby mimicking ulcerative or Crohn colitis. Granulomas were found in 3 patients (19%). CMV was detected in 1 patient. The appendix from 1 patient showed Cryptosporidium and acute serositis with a paucity of plasma cells and an increase in apoptosis. The gallbladder from 1 patient showed acute cholecystitis, and another patient's gallbladder lacked plasma cells.

CONCLUSIONS

GI tract CVID displays a wide spectrum of histologic patterns. Its features can mimic lymphocytic colitis, collagenous enterocolitis, celiac disease, lymphocytic gastritis, granulomatous disease, acute graft-versus-host disease, and inflammatory bowel disease. In fact, in our series, we found patients with a prior diagnosis of celiac disease (25%) and inflammatory bowel disease (35%), including Crohn disease (15%). The diagnosis of CVID may be suspected on the basis of the lack of plasma cells in a GI biopsy, but because this feature is only present in about two-thirds of patients, the diagnosis cannot always be suggested in isolation of other clinical and laboratory findings.

Apoptotic cell death and its relationship to gastric carcinogenesis

AIM: To investigate the apoptotic process of cells within the intestinal metaplasia areas co-localizing with chronic gastritis and gastric carcinomas and to analyze the involvement of proteins regulating apoptosis in the process of intestinal metaplasia related gastric carcinogenesis.

METHODS: Forty-two gastric carcinoma and seventeen chronic gastritis cases were included in this study. All cases were examined for the existence of intestinal metaplasia. Ten cases randomly selected from each group were processed for TUNEL assay. TUNEL positive cells within the intestinal metaplasia areas, co-localizing either to gastric carcinoma or chronic gastritis, were counted and converted to apoptotic indices. In addition, p53, bcl-2 and bax expression patterns within these tissues were analyzed on the basis of immunohistochemistry.

RESULTS: Twenty-eight of the cases were intestinal and 14 of the cases were diffuse type adenocarcinomas. 64% (27/42) of the gastric carcinoma cases had intestinal metaplasia. Intestinal metaplasia co-localized more with intestinal type carcinomas compared with diffuse type carcinomas [75% (21/28) vs 42% (6/14), respectively; P≤ 0.05]. The mean apoptotic index in tumor cells was 0.70 ± 0.08. The mean apoptotic index in intestinal metaplasias co-localizing to tumors was significantly higher than that of intestinal metaplasias co-localizing to chronic gastritis (0.70 ± 0.03 vs 0.09 ± 0.01, respectively; P≤ 0.05). p53 positivity was not observed in areas of intestinal metaplasia adjacent to tumors or chronic gastritis. Intestinal metaplasia areas adjacent to tumors showed lower cytoplasmic bcl-2 positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [55.5% (15/27) vs 70.5% (12/17), respectively]. On the other hand, intestinal metaplasia areas adjacent to tumors showed significantly higher cytoplasmic bax positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [44.4% (12/27) vs 11.7% (2/17), respectively; P≤ 0.05].

CONCLUSION: Existence of apoptotic cells on the basis of TUNEL positivity is shown in intestinal metaplasias co-localizing to both diffuse and intestinal type gastric cancers in this study. Our results also suggested bax expression dependent induction of apoptosis especially in intestinal metaplasia areas adjacent to tumors. These findings strongly support the involvement of apoptotic mechanisms in the process of gastric carcinogenesis especially in the transition from intestinal metaplasia to gastric cancer. It may be suggested that induction of apoptosis in intestinal metaplasia areas adjacent to tumors may involve different mechanisms than induction by chronic inflammation.

Role of bacterial strain diversity of Helicobacter pylori in gastric carcinogenesis induced by N-methyl-N-nitrosourea in Mongolian gerbils

AIM

Helicobacter pylori is known to enhance gastric carcinogenesis induced by chemical carcinogens. We previously demonstrated that infection with H. pylori strain SS1 did not enhance such carcinogenesis in C57BL/6 mice. Whether this result was due to the bacterial strain SS1 or to the experimental host, C57BL/6 mice, should be addressed. Therefore, we examined whether H. pylori strains introduced to the same host (Mongolian gerbils) differed in carcinogenicity.

MATERIALS AND METHODS

H. pylori TN2GF4 strain (CagA(+), VacA(+)) and SS1 strain (CagA functionally(-), VacA(-)) were infected to Mongolian gerbils (n = 126). In the first experiment (induction of gastritis), histologic change in gastric mucosa of gerbils infected by H. pylori (TN2GF4, SS1, vehicle) without N-methyl-N-nitrosourea (MNU) at 1 month or 6 months was assessed. In the second experiment (experimental carcinogenesis), H. pylori (TN2GF4, SS1, vehicle) was inoculated to the gerbils after administration of MNU for 10 weeks, and the number of cancers and histopathologic changes at week 54 were assessed.

RESULTS

In the first experiment, activity and inflammation in the TN2GF4 group were significantly greater than in the SS1 group at 1 month, while no significant difference was noted at 6 months. On the other hand, intestinal metaplasia and atrophy were significantly greater with TN2GF4 than with SS1 at 6 months but not at 1 month. In studies on experimental carcinogenesis, microscopically, 47.8% (11/23), 26% (7/26), and 0% (0/26), of animals had gastric adenocarcinoma in the MNU + TN2GF4 group, MNU + SS1 group, and MNU alone group, respectively.

CONCLUSION

Both H. pylori strains, TN2GF4 and SS1, promoted carcinogenesis in Mongolian gerbils. The severity of gastritis and destruction and restoration of gastric mucosa may be related to gastric carcinogenesis. That the SS1 strain significantly accelerated carcinogenesis only in Mongolian gerbils and not in C57BL/6 mice suggests the crucial role of host factors in carcinogenesis by H. pylori infection.

Prevalence of chronic atrophic gastritis in different parts of the world

Chronic atrophic gastritis (CAG) is a well-established precursor of intestinal gastric cancer, but epidemiologic data about its occurrence are sparse. We provide an overview on studies that examined the prevalence of CAG in different parts of the world. Articles containing data about the prevalence of chronic atrophic gastritis in unselected population samples and published until November 2005 were identified by searching the MEDLINE database. Furthermore, the references in the identified publications were screened for additional suitable studies. Studies comprising at least 50 subjects were included. Forty-one studies providing data on the prevalence of CAG in unselected population samples could be identified. CAG was determined by gastroscopy in 15 studies and by pepsinogen serum levels in 26 studies. Although results are difficult to compare due to the various definitions of CAG used, a strong increase with age, the lack of major gender differences, and strong variations between populations and population groups (in particular, relatively high rates in certain Asian populations) could be observed quite consistently. We conclude that CAG is relatively common among older adults in different parts of the world, but large variations exist. Large-scale international comparative studies with standardized methodology to determine CAG are needed to provide a coherent picture of the epidemiology of CAG in various populations. Noninvasive measurements of CAG by pepsinogen levels may be particularly suited for that purpose.

Promoter methylation of helicase-like transcription factor is associated with the early stages of gastric cancer with family history

BACKGROUND

To investigate the clinicopathological significance of promoter methylation of the helicase-like transcription factor (HLTF) in primary gastric cancer.

PATIENTS AND METHODS

Two-hundred fifty six patients participated in this study. Methylation status of HLTF gene was evaluated in fresh-frozen tissues by the methylation-specific polymerase chain reaction. All statistical analyses were two-sided, with a 5% type I error rate.

RESULTS

Aberrant methylation of HLTF was found in 98 (38%) of 256 gastric cancer patients. HLTF methylation was significantly associated with a family history in the early stages of gastric cancer, regardless of histologic types. In intestinal-type cases, HLTF methylation occurred in 15 (56%) of 27 patients with family histories, and in 26 (31%) of 85 patients without family histories (P = 0.02). In diffuse-type cases, patients with family histories were also found to exhibit a higher prevalence of HLTF methylation than those without family histories (61% vs. 34%; P = 0.009). HLTF methylation in both of the histologic types occurred in about 70-90% of the early stage cases in which the patient had a family history and in 15-30% of cases in which the patient did not have a family history. In our multivariate logistic regression analysis, the stage 1-2 cases with family histories were determined to carry a higher risk of HLTF methylation than did the stage 3-4 cases without family histories in both the intestinal-type (OR = 6.01, 95% CI = 1.20-30.01, P = 0.02) and the diffuse-type cancers (OR = 8.25, 95% CI = 1.67-40.86, P = 0.009).

CONCLUSIONS

These results suggest that HLTF methylation may play a crucial role in the early stages of gastric carcinogenesis in patients with family histories and may be a valuable susceptible marker for the risk of gastric cancer in individuals with family histories.

Coordinate increase of telomerase activity and c-Myc expression in Helicobacter pylori-associated gastric diseases

AIM: To detect the telomerase activity and c-Myc expression in gastric diseases and to examine the relation between these values and Helicobacter pylori (H pylori) as a risk factor for gastric cancer.

METHODS: One hundred and seventy-one gastric samples were studied to detect telomerase activity using a telomerase polymerase chain reaction enzyme linked immunosorbent assay (PCR-ELISA), and c-Myc expression using immunohistochemistry.

RESULTS: The telomerase activity and c-Myc expression were higher in cancers (87.69% and 61.54%) than in noncancerous tissues. They were higher in chronic atrophic gastritis with severe intestinal metaplasia (52.38% and 47.62%) than in chronic atrophic gastritis with mild intestinal metaplasia (13.33% and 16.67%). In chronic atrophic gastritis with severe intestinal metaplasia, the telomerase activity and c-Myc expression were higher in cases with H pylori infection (67.86% and 67.86%) than in those without infection (21.43% and 7.14%). c-Myc expression was higher in gastric cancer with H pylori infection (77.27%) than in that without infection (28.57%). The telomerase activity and c-Myc expression were coordinately up-regulated in H pylori infected gastric cancer and chronic atrophic gastritis with severe intestinal metaplasia.

CONCLUSION: H pylori infection may influence both telomerase activity and c-Myc expression in gastric diseases, especially in chronic atrophic gastritis.

Amelioration of oxidative stress with ensuing inflammation contributes to chemoprevention of H. pylori-associated gastric carcinogenesis

The gastric inflammatory response provoked by Helicobacter pylori (H. pylori) consists of infiltrations by neutrophils, lymphocytes, and macrophages, resulting in varying degrees of epithelial cell damage. H. pylori-associated inflammation not only activates various oxidant-producing enzymes such as NADPH oxidase and inducible nitric oxide synthase, but also lowers the antioxidant ascorbic acid in the stomach. Reactive oxygen metabolites and nitrogen metabolites generated by these enzymes react with each other to generate new or more potent reactive species. The specific types of cellular damage resulting from reactive oxygen metabolites include lipid peroxidation, protein oxidation, and oxidative DNA damage. All of these oxidative products can result in biochemical changes leading to cancer. A positive association has been demonstrated between H. pylori infection and gastric adenocarcinoma with increased oxidative stress. Therefore, appropriate treatment to reduce oxidative stress would be expected to prevent subsequent gastric carcinogenesis through lessening of H. pylori-associated inflammation. This review will provide evidence that antiinflammatory regimens can decrease the development of tumors and the amelioration of gastric inflammation might lead to chemoprevention strategies by the attenuation of oxidative stress.

Immunohistochemical expression of Fhit protein in Helicobacter pylori related chronic gastritis, gastric precancerous lesions and gastric carcinoma: correlation with conventional clinicopathologic parameters

OBJECTIVE

Our purpose was to investigate the immunohistochemical expression of Fhit protein in chronic Helicobacter pylori related gastritides, gastric epithelial dysplasia and gastric carcinoma.

DESIGN

Because a subset of chronic H. pylori related gastritides, precancerous lesions and gastric tumours were found to be either entirely negative or to minimally express Fhit protein, it is suggested that alteration of the carcinogen susceptible fragile region within the FHIT gene is an early event in a subset of gastric adenocarcinomas.

METHODS

We carried out immunohistochemical tests on archived material of formalin fixed, paraffin embedded tissues, using the anti-FHIT antibody and the streptavidin-biotin-peroxidase method, in a total of 135 gastric lesions (76 biopsies and 59 surgically resected gastric adenocarcinomas).

RESULTS

In this study, 79% of H. pylori related gastritides showed that the Fhit protein was either completely absent or there was a marked reduction of immunostaining. Similar results were obtained for 76.4% of cases of chronic gastritides with low and high-grade dysplasia, and 56% of gastric adenocarcinomas. A negative result for Fhit protein immunostaining was strongly associated with H. pylori infection (P = 0.0001) and with epithelial dysplasia (P = 0.01) but not with intestinal metaplasia or degree of activity. Additionally, negative or reduced immunostaining for Fhit was associated with the degree of dysplasia and progress of a subset of these lesions to infiltrating adenocarcinoma (P = 0.02). In gastric adenocarcinomas negative or weak immunostaining of the Fhit protein correlated with the histological grade (P = 0.01) and clinical stage of the disease (P = 0.01).

CONCLUSIONS

Our results suggest that, because Fhit protein immunostaining is completely absent in (1) the majority of H. pylori related chronic gastritides, (2) a subset of gastric dysplastic lesions, and (3) a proportion of primary gastric adenocarcinomas, irrespective of histological type, it can play an important role in the early development and progression of some gastric cancers.

Helicobacter pylori and telomerase activity in intestinal metaplasia of the stomach

BACKGROUND

Helicobacter pylori (H. pylori) has been considered a definitive carcinogen in gastric cancer. Telomerase is activated in gastric cancer and some premalignant gastric lesions, including intestinal metaplasia (IM). In this study, we evaluated the relationships of both H. pylori infection and telomerase activity with endoscopic and histologic features in IM. The effects of H. pylori eradication on endoscopic, histologic and biochemical changes were evaluated.

METHODS

Endoscopic biopsies were obtained from 43 patients with IM for rapid urease, histologic and telomerase tests. The endoscopic and histologic features, H. pylori infection and telomerase were assessed. After H. pylori eradication, 15 patients were re-evaluated and compared after 4 months.

RESULTS

Thirty-four (79.1%) patients were infected with H. pylori. The incidence of H. pylori infection was borderline correlated to the severity of IM (p = 0.076). Telomerase was elevated in eight (18.6%) patients. Telomerase tends to be high in subtype III and endoscopic grade III of IM. After H. pylori eradication, endoscopic extent (p = 0.039) and histologic severity (p = 0.074) showed improvements, and telomerase decreased significantly (p = 0.0001).

CONCLUSION

Our data suggest that telomerase is associated with the severity and extent of IM and that H. pylori eradication improves the endoscopic and histologic features in IM, and decreases telomerase activity. H. pylori eradication can be considered one of the methods to prevent gastric cancer in patients with H. pylori-infected IM. Further long-term and large-scaled study will be needed.

Gastric mucosal atrophy: interobserver consistency using new criteria for classification and grading

BACKGROUND AND AIMS

Considerable difficulties persist amongst pathologists in agreeing on the presence and severity of gastric atrophy. An international group of pathologists pursued the following aims: (i) to generate an acceptable definition and a simple reproducible classification of gastric atrophy; and (ii) to develop guidelines for the recognition of atrophy useful for increasing agreement among observers.

METHODS

After redefining atrophy as the 'loss of appropriate glands' and examining histological samples from different gastric compartments, three categories were identified: (i) negative; (ii) indefinite; (iii) atrophy, with and without intestinalization. Atrophy was graded on a three-level scale. Interobserver reproducibility of the classification was tested by kappa statistics (general and weighted) in a series of 48 cases.

RESULTS

The medians of the general agreement and weighted kappa values were 0.78 and 0.73, respectively. The weighted kappa coefficients, obtained by cross-tabulating the evaluation of each pathologist against all others, were, with only one exception, > 0.4 (moderate to excellent agreement).

CONCLUSIONS

By using the definition of atrophy as the loss of appropriate glands and distinguishing the two main morphological entities of metaplastic and non-metaplastic types, a high level of agreement was achieved by a group of gastrointestinal pathologists trained in different cultural contexts.

Effect of Helicobacter pylori-induced cyclooxygenase-2 on gastric epithelial cell kinetics: implication for gastric carcinogenesis

BACKGROUND

Cyclooxygenase (COX)-2 induced by Helicobacter pylori is thought to enhance gastric carcinogenesis by affecting the maintenance of epithelial homeostasis.

MATERIALS AND METHODS

Gastric biopsies from 160 subjects, 97 with nonulcer dyspepsia (47 H. pylori negative, 50 H. pylori positive) and 63 with gastric cancer were examined immunohistochemically for COX-2 expression, cell proliferation and apoptotic indices.

RESULTS

COX-2 expression in corpus was significantly higher in H. pylori positive than in negative non-ulcer dyspepsia (NUD) (p <.05). Regardless of site, gastric cancer subjects had higher COX-2 expression in both antrum and corpus compared with H. pylori negative and positive NUD (p <.005). Proliferation was higher in cancer and H. pylori positive than in negative NUD (p <.0001). Moreover, cancer had enhanced proliferation than H. pylori positive NUD in corpus greater (p =.0454) and antrum lesser (p =.0215) curvatures. Apoptosis was higher in H. pylori positive than in negative NUD (p <.05). However, both had a higher index than the cancer subjects (p <.0001). Apoptosis : proliferation ratio was higher in corpus of H. pylori negative than in positive NUD in greater (p =.0122) and lesser (p =.0009) curvatures. However, both had a higher A:P ratio than cancer cases (p =.0001). A negative correlation between COX-2 expression and A:P ratio was found in corpus greater (r = -.176, p =.0437) and lesser (r = -.188, p =.0312) curvatures.

CONCLUSION

The expression of COX-2 is associated with disruption in gastric epithelial kinetics and hence may play a role in gastric carcinogenesis.

Atrophy-metaplasia-dysplasia-carcinoma sequence in the stomach: a reality or merely an hypothesis?

The results of recent investigations have suggested that the old hypothesis of an atrophy-metaplasia-dysplasia-carcinoma sequence in the stomach needs to be qualified. The most common cause of intestinal metaplasia is Helicobacter pylori gastritis. The consequence of this intestinal metaplasia is focal atrophy. Helicobacter pylori infection may also trigger an autoimmune gastritis of the corpus mucosa, with atrophy and intestinal metaplasia. Most intestinal metaplasias are only 'paracancerous' but not 'precancerous' lesions. Diffuse gastric carcinomas, such as the signet ring cell carcinoma, arise independently of intestinal metaplasia. Histogenetically, numerous carcinomas of the stomach are primarily of the gastric type, and may secondarily change into the intestinal type.High-grade intra-epithelial neoplasias (dysplasias) detected during the biopsy-based diagnostic work-up appear to be a marker for carcinoma and must, therefore, be removed endoscopically. The detection of intestinal metaplasia in routinely obtained biopsy material is subject to sampling error and is, therefore, not a suitable marker for an increased risk of a gastric carcinoma developing. As an alternative, the concept of gastritis of the carcinoma phenotype, which is more frequently found in early gastric carcinomas and in the relatives of gastric carcinoma patients, has been developed. In this concept, the diffuse parameters of grade and activity of the gastritis in the antrum and corpus, which are independent of sampling error, are subjected to a comparative analysis. A risk gastritis of the carcinoma phenotype is diagnosed when the grade and activity of the gastritis in the corpus are at least equally as pronounced as in the antrum. Currently, this concept is being tested in a prospective ongoing study. Future studies must show whether, and if so which, immunohistochemical or molecular-genetically detectable changes can be applied as risk markers in the diagnostic work-up. Helicobacter pylori eradication probably does not lead to complete regression of the intestinal metaplasia and ensuing focal atrophy. However, eradication of H. pylori does lead to the normalization of changes that can lead to mutations of the stem cells of the gastric mucosa (free radicals, nitric oxide, cell proliferation and vitamin C secretion).

A phenotypic change of small intestinal epithelium to colonocytes in small intestinal adenomas and adenocarcinomas

OBJECTIVE

Using a novel monoclonal antibody (mAb Das-1) that specifically reacts with colon epithelium, we examined if there is a phenotypic change of small intestinal enterocytes toward colonocytes in small intestinal neoplastic tissue.

METHODS

Tissue sections of the small intestine consisting of adenomas (n = 20, five with histories of familial polyposis), adenocarcinomas (eight primary and one metastatic from colon). carcinoids (n = 2), and hyperplastic polyps (n = 3) were examined by a sensitive immunoperoxidase assay using mAb Das-1 (IgM isotype). Normal jejunal (n = 10) and colonic (n = 10) biopsy specimens were also included as additional controls.

RESULTS

mAb Das-1 reacted with normal colonic epithelium but not with jejunal mucosa. However, mAb Das-1 reacted strongly with each of the five adenomas (100%) from patients with histories of familial polyposis, but only five of 15 (33%) of the adenomas from nonfamilial polyposis patients, and each of the eight (100%) adenocarcinomas of the small intestine (p < 0.001). The reactivity with the adenomas from nonfamilial polyposis patients was very focal, whereas in the adenomas with familial polyposis the reactivity was more extensive. Each of the eight carcinomas reacted strongly with mAb Das-1. Adjacent normal small intestinal mucosa did not react. Hyperplastic polyps and the carcinoids did not react with mAb Das-1.

CONCLUSION

These data demonstrate a phenotypic change in small intestinal epithelium toward the colonic phenotype, particularly in familial polyposis and in adenocarcinomas. mAb Das-1 may be clinically useful in identifying small intestinal adenomas with "high risk" for malignancy, such as in familial polyposis.

The phenotype of gastric mucosa coexisting with Barrett's oesophagus

BACKGROUND/AIMS

Barrett's oesophagus complicates the gastro-oesophageal acid reflux. Helicobacter pylori infection, particularly with cagA positive strains, induces inflammatory/atrophic lesions of the gastric mucosa, which may impair acid output. No systematic study has investigated the phenotype of the gastric mucosa coexisting with Barrett's oesophagus. This study was designed to identify the phenotype of gastric mucosa associated with Barrett's oesophagus.

METHODS

In this retrospective case control study, the phenotype of the gastric mucosa was histologically characterised in 53 consecutive patients with Barrett's oesophagus and in 53 (sex and age matched) non-ulcer dyspeptic controls. Both patients and controls underwent extensive sampling of the gastric mucosa (two antral, one incisural, and two oxyntic biopsies). Intestinal metaplasia (IM) was categorised (type I, complete IM; types II and III, incomplete IM) by the high iron diamine stain; cagA status was ascertained by genotyping.

RESULTS

Helicobacter pylori was present in 19 of the 53 patients with Barrett's oesophagus and in 30 of the 53 controls (p < 0.02); eight of the 19 patients with Barrett's oesophagus and 28 of the 35 controls harboured cagA positive H pylori (p < 0.03). The histological severity of non-atrophic gastritis detected in the controls was significantly higher than that detected in the patients with Barrett's oesophagus (p < 0.0001). Multifocal atrophic gastritis was present in 4% of the patients with Barrett's oesophagus and in 23% of controls (p < 0.01). The odds ratio for the association between multifocal atrophic gastritis and Barrett's oesophagus was 0.20 (95% confidence interval, 0.006 to 0.60). Gastric IM was detected in 13.2% of the patients with Barrett's oesophagus and in 30.1% of the controls (p < 0.03). Type III IM at the gastric mucosa was only detected among controls.

CONCLUSIONS

Barrett's oesophagus is associated with a low prevalence of H pylori cagA positive infection and multifocal atrophic gastritis. This pathobiological pattern is considered to be associated with a low risk of distal gastric cancer.

Effect of lifestyle, smoking, and diet on development of intestinal metaplasia in H. pylori-positive subjects

OBJECTIVES

This study aimed to evaluate the influence of environmental and sociodemographic factors and the effect of smoking, alcohol, and dietary habits on the risk of gastric intestinal metaplasia (IM) in Helicobacter pylori-infected subjects.

METHODS

The investigation was based on 2598 consecutive volunteer blood donors tested for the presence of antibodies against H. pylori from March 1995 to March 1997. Endoscopy with multiple biopsies was offered to all H. pylori-positive, symptomatic subjects. The presence or absence of IM was diagnosed by gastric biopsies. A serologically H. pylori-positive subject with gastric IM was defined as a case, whereas serologically H. pylori-positive subjects without IM were used as controls. All patients answered a detailed questionnaire collecting sociodemographic characteristics and smoking, alcohol drinking, and dietary habits. Odds ratios (ORs) and their 95% CIs were estimated by unconditional logistic regression, including terms for age and sex, to assess the association between the data collected and IM.

RESULTS

Three hundred forty-four subjects with serological H. pylori infection and upper-GI symptoms underwent GI endoscopy, during which biopsies were taken for histological diagnosis. Histology revealed metaplasia in 74 subjects (21.5%). Incomplete IM was found in 37.8% of these cases. No significant associations were found between IM and anthropometric or sociodemographic factors. There was a significant association between age and IM (chi2 for trend, 6.67; p value, 0.009). Current smokers of over 20 cigarettes per day had a 4-fold risk of IM (OR, 4.75, 95% CI, 1.33-16.99). A 2-fold increased risk was found for high butter consumers (OR, 2.17; 95% CI, 1.14-4.11). No significant specific associations were found between the variables studied and complete or incomplete IM.

CONCLUSIONS

This study found that smoking and high butter consumption may increase the risk of having gastric IM in H. pylori-positive subjects.

Ascorbic acid and intestinal metaplasia in the stomach: a prospective, randomized study

BACKGROUND

Intestinal type metaplasia plays a role in intestinal type gastric carcinoma development. Ascorbic acid demonstrates a protective effect against gastric carcinogenesis, due to its ability to inactivate oxygen free-radicals as well as its nitrite-scavenging effects.

AIM

To assess whether long-term ascorbic acid administration following Helicobacter pylori eradication could affect intestinal metaplasia regression in the stomach.

METHODS

Sixty-five patients were included in the study. The inclusion criterion was the presence of intestinal metaplasia on the gastric mucosa after H. pylori eradication. An upper gastrointestinal endoscopy was performed and 3 biopsy specimens were taken in the antrum, 3 in the gastric body, and 2 in the incisura angularis. Patients were randomized to receive 500 mg of ascorbic acid o.d., after lunch (32 patients) for 6 months or no treatment (33 patients). All patients underwent to endoscopic control at the end of the 6 months.

RESULTS

H. pylori infection recurrence was detected in 6 (9.4%) patients (three from each group), and these patients were excluded from further analysis. We were unable to find evidence of intestinal metaplasia in any biopsied site of the gastric mucosa in 9/29 (31%) patients from the ascorbic acid group and in 1/29 (3.4%) of the patients from the control group (P=0.006). Moreover, a further six (20.7%) patients from the ascorbic acid group presenting chronic inactive pangastritis with widespread intestinal metaplasia at entry, showed less extensive antritis with intestinal metaplasia at control, whilst a similar finding was only seen in one patient from the control group (P=0.051).

CONCLUSION

The administration of ascorbic acid significantly helps to resolve intestinal metaplasia of the gastric mucosa following H. pylori eradication, and its use as a chemoprevention treatment should be considered.

Topographic patterns of intestinal metaplasia and gastric cancer

OBJECTIVE

The role of intestinal metaplasia in gastric oncogenesis has been demonstrated by both cross-sectional and longitudinal studies. This study was designed to determine whether, in a population at high risk for gastric cancer, different topographical patterns and phenotypes of intestinal metaplasia were associated with different degrees of cancer risk.

METHODS

A total of 68 Colombian patients with gastric cancer and 67 controls with nonulcer dyspepsia were studied by an extensive biopsy protocol. Intestinal metaplasia was assessed semiquantitatively by histology and was characterized histochemically. In both patients and controls, the Spearman's correlation test was applied to the test if the gastric distribution of metaplastic lesions resulted in specific topographical patterns associated with different risks for cancer.

RESULTS

Four topographical patterns of intestinalization emerged: 1) "Focal," in 14 cancer patients and 16 controls; 2) "Antrum-predominant," in seven cancer patients and six controls; 3) "Magenstrasse" (involving the lesser curvature from cardia to pylorus) in 25 cancer patients and four controls. This pattern was associated with higher cancer risk (OR = 5.7; 95% CI: 1.3-26) than were the two less extensive patterns; and 4) "Diffuse," involving essentially the entire gastric mucosa with the exception of the fundus, was unique to 13 cancer patients. The OR for cancer was 12.2; 95% CI: 2.0-72.9. Incomplete-type metaplasia significantly correlated with the extent of total metaplasia and was also associated with greater cancer risk.

CONCLUSIONS

In a population with high risk for gastric cancer, the extension of intestinal metaplasia correlates with the extent of its "incomplete" phenotype and is significantly associated with increased cancer risk. Both the extent and location of intestinal metaplasia along the lesser curvature (from the cardia to the prepyloric zones) identify patients with the highest cancer risk.

Helicobacter pylori. One bacterium and a broad spectrum of human disease! An overview

Since the historical rediscovery of gastric spiral Helicobacter pylori in the gastric mucosa of patients with chronic gastritis by Warren and Marshall in 1983, peptic ulcer disease has been largely viewed as being of infectious aetiology. Indeed, there is a strong association between the presence of H. pylori and chronic active gastritis in histology. The bacterium can be isolated in not less than 70% of gastric and in over 90% of duodenal ulcer patients. Eradication of the organism has been associated with histologic improvement of gastritis, lower relapse rate and less risk of bleeding from duodenal ulcer. The bacterium possesses several virulence factors enabling it to survive the strong acid milieu inside the stomach and possibly damaging host tissues. The sequence of events by which the bacterium might cause gastric or duodenal ulcer is still not fully elucidated and Koch's postulates have never been fulfilled. In the majority of individuals, H. pylori infection is largely or entirely asymptomatic and there is no convincing data to suggest an increase in the prevalence of peptic ulcer disease among these subjects. An increasingly growing body of literature suggests an association between colonization by H. pylori in the stomach and a risk for developing gastric mucosa-associated lymphoid tissue (MALT), MALT lymphoma, gastric adenocarcinoma and even pancreatic adenocarcinoma. The bacterium has been implicated also in a number of extra-gastrointestinal disorders such as ischaemic heart disease, ischaemic cerebrovascular disease, atherosclerosis, and skin diseases such as rosacea, but a causal role for the bacterium is missing. Eradication of H. pylori thus seems to be a beneficial impact on human health. Various drug regimens are in use to eradicate H. pylori involving the administration of three or four drugs including bismuth compounds, metronidazole, clarithromycin, tetracyclines, amoxycillin, ranitidine, omeprazole for 1-2 weeks. The financial burden, side effects and emergence of drug resistant strains due to an increase in the use in antibiotics for H. pylori eradication therapy need further reconsideration.

An 18-year follow-up study of chronic gastritis and Helicobacter pylori association of CagA positivity with development of atrophy and activity of gastritis

BACKGROUND

We wanted to evaluate the course of chronic gastritis and its association with Helicobacter pylori and CagA seropositivity in an adult sample from Saaremaa (Estonia) during an 18-year follow-up.

METHODS

Seventy persons (31 men, 39 women; median age, 57.5 years) from a primary sample of 304 subjects endoscoped in 1979 were reinvestigated by endoscopy and biopsy in 1997. The state of the gastric mucosa and the presence of H. pylori in histologic sections from the antrum and corpus were assessed both in 1979 and 1997 in 66 subjects in accordance with the Sydney system, and H. pylori status in all 70 subjects was determined with the enzyme-linked immunosorbent assay (ELISA). Anti-CagA IgGs were determined with the ELISA, using the recombinant fragment of CagA.

RESULTS

During an 18-year follow-up 11% of the subjects developed atrophy in the antrum, whereas 35% developed it in the corpus. Development of atrophy in the corpus and the appearance of intestinal metaplasia in the antrum were associated with increased activity of gastritis both in the initial and last follow-up biopsies. Anti-CagA positivity was found in 71% of H. pylori-seropositive persons (94% of subjects). There was a significant association between CagA positivity and the activity of gastritis, the presence of atrophy or damage to surface epithelial cells in the antrum and in corpus mucosal biopsy specimens at the last follow-up endoscopy.

CONCLUSION

The CagA-positive strains of H. pylori enhance the development of atrophic gastritis compared with CagA-negative strains.

Helicobacter pylori infection enhances glandular stomach carcinogenesis in Mongolian gerbils treated with chemical carcinogens

Helicobacter pylori (Hp) is thought to be a stomach carcinogen from epidemiological findings. To determine the effects of infection with the bacteria on experimental carcinogenesis, a study of the glandular stomach of Mongolian gerbils (MGs) was performed. Male MGs were treated with N-methyl-N'-nitro-N-nitrosoguanidine followed by inoculation with Hp or infected with Hp followed by N-methyl-N'-nitro-N-nitrosoguanidine administration. Animals were killed at week 50, and their excised stomachs underwent microbiological and histopathological examinations. In addition, a serological investigation was performed. The incidences of adenocarcinomas were significantly higher in animals treated with 60 or 300 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine for 10 weeks followed by Hp inoculation or Hp followed by 20 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine for 30 weeks than in the respective controls. Moreover, tumour-bearing animals had higher titres of anti-Hp antibodies than tumour-free animals. Of interest was the finding that a dose of 100 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine given to infected gerbils eradicated the Hp in about half the animals, with a concomitant reduction in the promoting effect. No tumours were found in animals infected with Hp without N-methyl-N'-nitro-N-nitrosoguanidine or non-treated gerbils. Hp infection enhances glandular stomach carcinogenesis in MGs treated with N-methyl-N'-nitro-N-nitrosoguanidine. Animals with high titres of anti-Hp antibodies are at greatest risk of developing neoplasms.

Gastric pathology in cholecystectomy patients: role of Helicobacter pylori and bile reflux

The data regarding the role of Helicobacter pylori infection in patients with bile reflux are conflicting. Bile reflux is often observed after cholecystectomy. This study focuses on the role of H. pylori in gastric pathology of patients who had undergone cholecystectomy. Eighty-seven consecutive patients were included in the study. An upper gastrointestinal endoscopy was performed, and biopsy specimens were taken in the antrum, incisura angularis, and in the gastric body. The presence of bile reflux in gastric fluid at endoscopic examination was recorded. The overall H. pylori infection rate was 62%, with no difference between patients with (59.7%) and without (64%) endoscopic bile reflux (p = 0.67). The intestinal metaplasia rate in gastric mucosa was significantly higher in patients with both H. pylori and bile reflux than in patients without infection and bile reflux (36.4% vs. 5.6%, p = 0.02). Moreover, the mean number of years after cholecystectomy in patients with intestinal metaplasia was significantly higher than in those without metaplasia (21.1 +/- 7 vs. 11.5 +/- 8 years, p < 0.0001), whereas mean age did not differ significantly between groups (60.3 +/- 12 vs. 55.8 +/- 11 years, p = 0.14). Furthermore, we found four cases of gastric cancer, three with H. pylori infection. The mean number of years after cholecystectomy was significantly higher in patients with gastric cancer than in other patients (21.8 +/- 4 vs. 12.2 +/- 8 years, p = 0.009). This study found that H. pylori infection is frequent in cholecystectomized patients, also in the presence of endoscopic bile reflux. Bile reflux seems to act synergistically with H. pylori infection on gastric pathology.

Overexpression of p53 in different subtypes of intestinal metaplasia and gastric cancer

p53 immunostaining was evaluated in cancerous epithelia and adjacent intestinal metaplasia of 135 gastric cancer specimens. The differential p53 overexpression in different subtypes of intestinal metaplasia and gastric cancer suggests that type III intestinal metaplasia is the commonest lesion in dysplasia-carcinoma transition, particularly in the intestinal type of gastric cancer.

Reversal of fundic atrophy after eradication of Helicobacter pylori

OBJECTIVES

We sought to evaluate the effect of Helicobacter pylori eradication in patients with fundic atrophic gastritis.

METHODS

Acid secretion, gastric emptying, and histology were evaluated in 20 patients with fundic atrophic gastritis and H. pylori infection. After investigation, 10 patients (Group 1) received an eradicating treatment and 10 (Group 2) did not receive any treatment. One year later, the baseline investigations were repeated. Subsequently, patients in Group 2 received the same treatment given to patients in Group 1 and were reevaluated 12 months later. A further follow-up was performed in both groups 36 months after the treatment.

RESULTS

At 1-yr follow-up, all the patients in Group 1 were H. pylori negative whereas all the patients in Group 2 were still infected. In Group 1, there was a significant improvement of both fundic atrophy and acid secretion, compared with baseline (p < 0.01). In Group 2, no substantial modification of either histological or functional parameters was observed at the first follow-up; conversely, a significant (p < 0.01) improvement of fundic atrophy and acid secretion was detected in these patients 12 months after eradication of the bacterium. Histological pattern remained unchanged at 36 months of follow-up in both groups. Gastric emptying remained, on the average, unaffected by the treatment; however, three patients with delayed gastric emptying at entry had normal gastric emptying after eradication of H. pylori.

CONCLUSIONS

Our data suggest that mucosal atrophy can be reduced or even reversed by the eradication of H. pylori, and this is associated with a recovery of gastric function.

Gastric cancer risk in relation to Helicobacter pylori infection and subtypes of intestinal metaplasia

Helicobacter pylori (H. pylori) infection and intestinal metaplasia (IM) are each associated with an increased risk of gastric cancer (GC). To explore further the influences of H. pylori and IM on GC, H. pylori and subtypes of IM were evaluated in 135 sex and age-matched case and control pairs. Odds ratios (ORs) with 95% confidence intervals of developing GC were calculated for each risk factor using multiple logistic regression analysis. ORs for H. pylori infection and IM were 2.43 (1.29-4.65) and 4.59 (2.58-8.16), respectively, and those for different IM subtypes gave values of 0.82 (0.28-2.36) for type I, 2.03 (0.95-4.34) for type II and 39.75 (14.34-110.2) for type III. Stratification analysis by histological subtype and stage of GC showed a particularly high OR for IM in intestinal type (12.8, 4.73-34.83) and early GC (6.40, 2.25-18.18). Our data indicate that both H. pylori and IM are related to GC risk. Type III IM is a more specific marker of premalignancy, with relevance, in particular, to the early and intestinal type of GC.

Meta-analysis of the relationship between Helicobacter pylori seropositivity and gastric cancer

BACKGROUND & AIMS

Reports in the literature regarding the relationship of Helicobacter pylori infection to gastric cancer are conflicting. The aim of this study was to identify the source of heterogeneity between studies.

METHODS

Meta-analysis of cohort or case-control studies with age- and/or sex-matched controls, providing raw data on H. pylori infection detected by serology, was used.

RESULTS

A fully recursive literature search identified 19 qualified studies with 2491 patients and 3959 controls. Test for homogeneity found a significant difference in odds ratio between patients with early and advanced gastric cancer (6.35 vs. 2.13; P = 0.01), patients with cardiac and noncardiac gastric cancer (1.23 vs. 3.08; P = 0.003), and population- and hospital-based controls (2.11 vs. 1.49; P < 0.001). The summary odds ratio for gastric cancer in H. pylori-infected patients is 1.92 (95% confidence interval [CI], 1.32-2.78), 2.24 (95% CI, 1.15-4.4), and 1.81 (95% CI, 1.16-2.84) for all studies, cohort, and case-control studies, respectively. H. pylori-infected younger patients have a higher relative risk for gastric cancer than older patients with odds ratios decreasing from 9.29 at age < or = 29 years to 1.05 at age > or = 70 years. H. pylori infection is equally associated with the intestinal or diffuse type of gastric cancer.

CONCLUSIONS

H. pylori infection is a risk factor for gastric cancer. The heterogeneity of reported results is caused by differences in the selection of controls, patient age, and the site and stage of gastric cancer.

Atrophic gastritis and intestinal metaplasia in Helicobacter pylori infection: the role of CagA status

OBJECTIVE

Helicobacter pylori (H. pylori) is a major factor in determining the risk for development of gastric adenocarcinoma through the intermediate steps of atrophic gastritis and intestinal metaplasia. Because H. pylori infection is highly prevalent in asymptomatic populations and only a few people develop cancer, additional factors may influence the risk for development of cancer, once infection is established. Some factors may pertain to differences among bacterial strains. Because infection by H. pylori strains possessing cagA (cytotoxin-associated gene A), a gene encoding a high-molecular-weight immunodominant antigen (CagA), is associated with enhanced induction of gastritis, the aim of our study was to evaluate potential differences in the prevalence and intensity of atrophy and intestinal metaplasia between CagA-positive and CagA-negative H. pylori-infected patients.

METHODS

Eighty H. pylori-infected patients among 120 consecutive dyspeptic patients referred for upper gastrointestinal endoscopy were studied. Six bioptic specimens were taken from the gastric antrum: five for histological examination, and one for urease test. The H. pylori status was determined by histology, CLO test, and serology (in a standardized ELISA) for serum IgG and IgA directed to H. pylori. The CagA status was determined by Western blotting to detect serum IgG antibodies to CagA. Gastritis was classified according to the Sydney System. A score from 0 to 3 was assigned to each of the following morphological variables: atrophy, intestinal metaplasia, and mononuclear and neutrophilic cell infiltration. The association between CagA status and histological features was assessed by means of the chi2 test for trend.

RESULTS

Among the 80 H. pylori-infected patients 53 (66%) were CagA seropositive and 27 (34%) were CagA seronegative. The mean age of the two groups was similar. CagA-positive patients had significantly higher scores for atrophy (p = 0.006), intestinal metaplasia (p = 0.01), and mononuclear (p < 0.001) and polymorphonuclear (p = 0.002) cell infiltration than did CagA-negative patients. No differences in contrast, were found for H. pylori density.

CONCLUSION

Infection with CagA-positive H. pylori strains is associated with an increased prevalence and intensity of antral atrophy and intestinal metaplasia, in addition to higher degrees of gastritis. Our results seem to suggest that the CagA status could be a helpful parameter to define a subgroup of H. pylori-infected patients at increased risk of developing gastric adenocarcinoma.

Helicobacter pylori promotes development of pepsinogen-altered pyloric glands, a preneoplastic lesion of glandular stomach of BALB/c mice pretreated with N-methyl-N-nitrosourea

H. pylori is thought to be a stomach carcinogen. Since no experimental model has hitherto been established to clarify the relationship between H. pylori and stomach carcinogenesis, the effects of infection with the bacteria on experimental carcinogenesis in the glandular stomach of mice were investigated. BALB/c mice were given salty diet or N-methyl-N-nitrosourea (MNU) and administered broth culture of H. pylori. The incidence of pepsinogen-altered pyloric glands, considered as precancerous lesions, was increased in the H. pylori inoculated group pre-treated with MNU. The findings provide the new experimental model demonstrating the relationship between stomach cancer and H. pylori.

Cytotoxin-associated gene A-positive Helicobacter pylori infection in the elderly. Association with gastric atrophy and intestinal metaplasia

To evaluate if the infection with strains of cytotoxin-associated gene A (CagA)-positive Helicobacter pylori is associated with either peptic ulcer and gastric atrophy or intestinal metaplasia in the elderly, we studied 71 H. pylori-positive patients older than 62 years old (34 men, 37 women; mean age, 77.5 years; range, 62-89 years) affected with gastric ulcer (GU) (n = 10), duodenal ulcer (DU) n = 22), or chronic gastritis (CG) (n = 39). H. pylori infection was documented by means of gastric histology, rapid urease test, and polymerase chain reaction (PCR) assay performed on gastric biopsies using two sets of primers: one for the ureC gene specific for H. pylori, and the second specific for the CagA gene. H. pylori-CagA positivity was significantly more common in patients with GU (9 of 10, 90%) than with DU (11 of 22, 50%; p < 0.05) or CG (17 of 39, 43.5%; p = 0.01). Gastric atrophy and intestinal metaplasia were significantly more common in CagA-positive patients than in CagA-negative patients (gastric atrophy: 40.54% vs 11.76, p = 0.007; intestinal metaplasia: 40.54% vs 14.70%, p = 0.01). No difference in prevalence of gastric atrophy and intestinal metaplasia was found in patients divided according to pathology (GU, DU, or CG). Logistic regression demonstrated that gastric atrophy and intestinal metaplasia were independent factors significantly associated with CagA-positivity (gastric atrophy: odds ratio = 4.53, 95% confidence interval 1.25-16.4; intestinal metaplasia: odds ratio = 3.44, 95% confidence interval 1.01-11.7). Our findings help to confirm the hypothesis that an infection with CagA-positive H. pylori strains may be catalytic in inducing gastric changes which can evolve into malignancies.

Is the study of human cancer-associated factors, the best or the only model for human carcinogenesis research? I. The question of Helicobacter pylori infection as an accused human gastric carcinogen

Experimental carcinogenesis has discovered and analyzed the inductive effect for one type of cancer, of single factors in given animal strains. Human carcinogenesis analyses the effect of associated factors on one cancer type incidence. It does not find any direct correlation and finds a lot of intermediary effects and mechanism between the factor and established carcinogenesis. Regarding Helicobacter pylori (HP), one realizes there is no statistical correlation between gastric infection and carcinoma. The only data which sustain its role is its possible effect in promoting atrophic gastritis with intestinal metaplasia, via the serum pepsinogen 1 reduction due to anti-HP immunoglobulin A (IgA) antibody. Intestinal metaplasia of the stomach is a condition increasing cell proliferation.