Gastric mucosal inflammation and epithelial cell turnover are associated with gastric cancer in patients with Helicobacter pylori infection

BACKGROUND: Infection with a virulent Helicobacter pylori strain is associated with gastric mucosal damage and the increased risk of gastric cancer. AIMS: To examine the characteristics of host gastric mucosal responses in patients with gastric cancer, histological grade of gastritis, gastric epithelial apoptosis, and proliferation were studied. METHODS: Thirty two patients with early gastric cancer and 32 sex and age matched controls were studied. All subjects were infected with a virulent H pylori strain (vacA s1/m1, cagA positive genotype). Biopsy specimens were taken from the antrum and the corpus of the stomach. The grade of gastritis was assessed according to the updated Sydney system. Apoptotic cells were detected using terminal uridine deoxynucleotidyl nick end labelling, and epithelial cell proliferation was determined by means of the Ki-67 labelling index. RESULTS: In patients with gastric cancer, significantly higher grades were observed when glandular atrophy (p < 0.05) and intestinal metaplasia (p < 0.01) were present in the antrum, and when mononuclear cell infiltration was present in the corpus (p < 0.05). The numbers of apoptotic cells were increased in patients with cancer (p < 0.05) and the apoptotic index correlated significantly with the grade of glandular atrophy. Epithelial cell proliferation was more likely to be increased in mucosa where intestinal metaplasia was present. CONCLUSIONS: Infection with H pylori causes increased gastric epithelial apoptosis, resulting in more severe glandular atrophy in patients with gastric cancer. Increased damage of gastric epithelial DNA and the presence of more severe atrophic gastritis might contribute to the development of gastric cancer.     

Atrophic gastritis in young children and adolescents

BACKGROUND: Helicobacter pylori associated gastric cancer arises via a multistage process, with atrophic gastritis being the precursor lesion. Helicobacter pylori is typically acquired in childhood, yet little is known of the prevalence of atrophic gastritis in childhood. AIM: To study atrophic gastritis among children from countries with high gastric cancer incidence. METHODS: Sections from topographically mapped gastric biopsy specimens from children undergoing clinically indicated endoscopy in Korea and Colombia were evaluated using visual analogue scales. Atrophy was defined as loss of normal glandular components, including replacement with fibrosis, intestinal metaplasia (IM), and/or pseudopyloric metaplasia of the corpus (identified by the presence of pepsinogen I in mucosa that was topographically corpus but phenotypically antrum). RESULTS: One hundred and seventy three children, 58 from Korea (median age, 14 years) and 115 from Colombia (median age, 13 years), were studied. Helicobacter pylori was present in 85% of Colombian children versus 17% of Korean children (p<0.01). Atrophic mucosa near the antrum-corpus border was present in 16% of children, primarily as pseudopyloric metaplasia (31%, IM; 63%, pseudopyloric metaplasia; 6%, both). The median age of children with corpus atrophy was 15 (range, 7-17) years. CONCLUSION: Gastric atrophy occurs in H pylori infected children living in countries with high gastric cancer incidence. Identification and characterisation of the natural history of H pylori gastritis requires targeted biopsies to include the lesser and greater curve of the corpus, starting just proximal to the anatomical antrum-corpus junction, in addition to biopsies targeting the antrum and cardia.     

Pathology of the gastric antrum and body associated with Helicobacter pylori infection in non-ulcerous patients: is the bacterium a promoter of intestinal metaplasia?

A series of 115 consecutive, non-ulcerous, dyspeptic patients were examined for Helicobacter pylori (H. pylori) colonization in the gastric antral and/or body mucosa using Giemsa staining. Findings were correlated with the presence and degree of activity of superficial gastritis, deep gastritis, atrophic gastritis and with the presence of intestinal metaplasia. The prevalence of H. pylori positivity was 61.7%. In 59 of the 71 positive patients (83%), H. pylori was detected in the antrum or in both the antral and oxyntic mucosa. In the remaining 12 positive patients, H. pylori was detected only in the oxyntic mucosa and in all these cases, the antrum showed intestinal metaplasia associated with atrophic gastritis (25%). In both antral and oxyntic mucosa, the activity of the gastritis was significantly correlated with H. pylori colonization. Linear logistic regression analysis showed that in patients with intestinal metaplasia the presence of H. pylori infection was significant in predicting the presence of more extensive intestinal metaplasia after adjusting for age. The prevalence of intestinal metaplasia types II and III was 65.5% in the H. pylori positive and 25% in the H. pylori negative patients. The antral mucosa is thought to be the elective site for H. pylori related histological lesions. At a later stage, H. pylori can be detected only in the oxyntic area while the antral mucosa shows extensive metaplastic or atrophic lesions. We would suggest that H. pylori plays a promotional role in the morphogenesis of intestinal metaplasia.     

The comparison of histologic gastritis in patients with duodenal ulcer, chronic gastritis, gastric ulcer and gastric cancer

This study was designed to investigate the differences of histologic gastritis according to the endoscopic diagnosis, and between H. pylori positive and negative gastritis, using the Sydney system. A total of 122 patients (42 duodenal ulcer, 31 chronic gastritis, 35 gastric ulcer and 14 gastric cancer) underwent endoscopy with biopsies from the antrum and body. Among the 122 patients, 104 (85%) were H. pylori positive. H. pylori density of the antrum was significantly higher in duodenal ulcer than in chronic gastritis, gastric ulcer, and gastric cancer. The positivity of intestinal metaplasia was lowest in duodenal ulcer and highest in gastric cancer. H. pylori density as well as grade of activity, inflammation and atrophy were significantly higher in the antrum than in the body in duodenal ulcer, while in chronic gastritis, gastric ulcer and gastric cancer there was no difference of H. pylori density, activity, inflammation and atrophy between the antrum and body. The grade of activity and chronic inflammation were significantly higher in H. pylori positive patients than in H. pylori negative patients in both the antrum and body. In conclusion, the gastritis of duodenal ulcer was mainly localized to the antrum, while the gastritis of chronic gastritis, gastric ulcer or gastric cancer was rather uniform in the antrum and body. H. pylori seemed to be related to the development of chronic inflammation and activity.     

Expression of melanoma differentiation associated gene 5 is increased in human gastric mucosa infected with Helicobacter pylori

Helicobacter pylori infection is associated with gastroduodenal diseases. Melanoma differentiation associated gene 5 (MDA5) plays a role in antiviral host defense. We investigated the effect of H pylori infection on MDA5 expression in human gastric mucosa. Biopsy samples from the antrum and corpus were obtained from 33 patients. MDA5 mRNA and protein were examined by real-time PCR and immunohistochemical staining. Histological gastritis was graded according to updated Sydney System. MDA5 mRNA was significantly increased in the antrum infected with H pylori. MDA5 protein positively stained in infiltrating mononuclear cells. MDA5 mRNA expression was significantly correlated with the grade of glandular atrophy (rs = 0.767) and intestinal metaplasia (rs = 0.748) in the corpus with H pylori infection. These results indicate that MDA5 may be involved in innate immune reactions against H pylori and associate with glandular atrophy and intestinal metaplasia in patients with H pylori infection.     

Helicobacter pylori infection and chronic gastritis in gastric cancer.

AIMS: To investigate the prevalence of Helicobacter pylori associated chronic gastritis in patients with gastric cancer. METHODS: Serum IgG antibodies for H pylori were determined in 54 consecutive patients with gastric carcinoma. The prevalence of H pylori in gastric mucosa was also examined histologically (modified Giemsa) in 32 patients from whom adequate biopsy specimens of the antrum and corpus were available. Thirty five patients with gastrointestinal tumours outside the stomach and 48 with non-gastrointestinal malignancies served as controls. RESULTS: Of the 54 patients, 38 (70%) had H pylori antibodies (IgG) in their serum (three additional patients had H pylori antibodies IgA, class specific but not IgG specific). This prevalence was significantly higher (p less than 0.05) than that (49%) in the 35 controls. No differences in prevalence of H pylori antibodies were found between gastric cancer cases of intestinal (IGCA) or diffuse (DGCA) type, both these types showing H pylori antibodies (IgG) in 71% of the patients. In the subgroup of 32 subjects, five patients had normal gastric mucosa and four showed corpus limited atrophy ("pernicious anaemia type" atrophy of type A). All of these nine patients had no evidence of current or previous H pylori infection in serum (no IgG antibodies) or in tissue sections (negative Giemsa staining). The remaining 23 patients had antral or pangastritis, and all had evidence of current or previous H pylori infection. CONCLUSIONS: H pylori associated chronic gastritis was the associated disease in 75% of the patients with gastric cancer occurring equally often in both IGCA and DGCA groups. About 25% of cases seem to have a normal stomach or severe corpus limited atrophy, neither of which showed evidence of concomitant H pylori infection.     

Histological study of chronic gastritis from the United Arab Emirates using the Sydney system of classification.

AIMS--To determine the prevalence of Helicobacter pylori in five main nationality groups with gastric ulcer, duodenal ulcer, and non-ulcer dyspepsia; and to determine the histopathological types of gastritis and assess the graded variables of Helicobacter associated gastritis. METHODS--Gastric antral and corpus biopsy specimens from 437 patients were examined for the prevalence of H pylori, 337 of which were classified and graded histologically according to the Sydney system. RESULTS--The overall colonisation rate of H pylori was 90%, and there was no significant difference between groups of different ethnic origins. The colonisation rates were 99%, 89%, and 78% in patients with duodenal ulcer, non-ulcer dyspepsia, and gastric ulcer, respectively. Helicobacter associated gastritis was the most common form of chronic gastritis (87%). H pylori density was greater in the antrum than the body. Gastric atrophy in helicobacter associated gastritis was seen in 54% of the cases (43% grade I, 10% grade II, 1% grade III) and increased the older the patients. Atrophy of the corpus alone was very rare (1%). Atrophy and intestinal metaplasia were more prevalent in patients with gastric ulcer than duodenal ulcer. CONCLUSION--The colonisation rate of H pylori was similar in the five groups studied and was almost invariably present in gastric biopsy specimens in patients with duodenal ulcer. H pylori associated gastritis was the most common form of gastritis. Atrophy was mainly of low grade and increased the older the patient.     

Endocrine neoplasm of the stomach. Study of thirteen cases

A Thirteen patients with primary endocrine neoplasm of the stomach were studied for 20 years. Six patients were male and 7 female with an age range of 33 to 77, mean age 57 years. Nine cases corresponded to well differentiated carcinoids and four to neuroendocrine carcinomas. Of the former, three were sporadic and six were associated with atrophic gastritis. These two forms of neoplasm showed important differences: those associated with atrophic gastritis had hypergastrinemia, all of the multiple small tumors confined to the corpus and fundus were well differentiated carcinoids associated with intestinal metaplasia and G cell hyperplasia in antrum and ECL cell hyperplasia in corpus and fundus. Tumors were clinically benign, with an excellent prognosis. All patients are currently alive with no evidence of neoplasm. In only one of these cases, antiparietal cell antibodies were documented; in three of them, extensive intestinal metaplasia probably due to Helicobacter pylori infection was found. In contrast, sporadic carcinoids were large isolated tumors originating in the antrum or corpus. Two patients died as a consequence of the neoplasm; all of them were moderately differentiated and in none of the cases we found evidence of endocrine hyperplasia. All were positive for generic endocrine markers and were focally positive to some of the specific hormone markers. Al four neuroendocrine carcinomas had a clinical course similar to that of gastric adenocarcinomas and were poorly differentiated large tumors. We conclude that gastric carcinoids associated with atrophic gastritis have an excellent prognosis. On the other hand, neuroendocrine carcinomas have a very poor prognosis with fatal outcome of patients. Sporadic carcinoids have an intermediate prognosis.     

Prevalence of gastric precancerous lesions in Ardabil, a high incidence province for gastric adenocarcinoma in the northwest of Iran

BACKGROUND/AIMS: Ardabil Province, in northwestern Iran, has the highest rate of gastric (predominantly cardia) adenocarcinoma in Iran. This study aimed to investigate the feasibility of endoscopic screening and to look for associated Helicobacter pylori infection and gastric precancerous lesions. METHODS: One thousand one hundred and five adult volunteers, residents of Ardabil and Meshkinshahr, districts, 40 years old and above were selected and invited by a simple random household canvass in rural and urban locations. Informed consents were obtained and upper gastrointestinal video endoscopy was performed to biopsy all visible lesions and standard sites in the antrum, corpus, and cardia. RESULTS: One thousand and eleven of the invited individuals agreed to participate, including 494 men and 517 women, with a mean (SD) age of 53.32 (10.39) years. Endoscopy was well tolerated by all subjects; 96.7% of antral and 80.7% of cardia mucosal biopsies were satisfactory. The urease test or histology for H pylori was positive in at least 89.2% of subjects. Histological evidence of mucosal atrophy was seen in 39.3% of antral and 21.9% of cardia samples. Chronic gastritis with or without activity, reactive atypia of glandular epithelium, intestinal metaplasia, dysplasia, and cancer were found in 95.1%, 38.0%, 8.7%, 0.2%, and 0.3% of antral and 85.3%, 22.9%, 3.8%, 0.3%, and 0.1% of cardiac biopsies, respectively. CONCLUSION: Endoscopic screening for upper gastrointestinal diseases was feasible and well tolerated in Ardabil, Iran. Most subjects showed H pylori infection. Atrophic gastritis, reactive atypia, and intestinal metaplasia were common in antrum, corpus, and cardia subsites.     

Bile reflux and intestinal metaplasia in gastric mucosa.

AIM: To determine associations between enterogastric bile reflux and gastric mucosal pathology. METHOD: A retrospective study using fasting gastric juice bile acid measurements and antral or prestomal biopsy specimens from 350 patients, 66 of whom had previously undergone surgery that either bypassed or disrupted the pyloric sphincter. RESULTS: Bile reflux was positively associated with reactive gastritis and negatively with Helicobacter pylori density. After stratification for previous surgery, age, and H pylori status, the histological feature most strongly associated with bile reflux was intestinal metaplasia, including all its subtypes. The prevalence of intestinal metaplasia was greatest in patients with both H pylori infection and high bile acid concentrations. Bile reflux was also positively associated with the severity of glandular atrophy, chronic inflammation, lamina propria oedema and foveolar hyperplasia. CONCLUSIONS: Bile reflux is a cause of reactive gastritis. It modifies the features of H pylori associated chronic gastritis. The changes are not confined to patients who have had surgery to their stomachs. The positive associations with atrophy and intestinal metaplasia have implications for models of gastric carcinogenesis.     

Response of IgG1 and IgG2 subclasses to Helicobacter pylori in subjects with chronic inflammation of the gastric mucosa, atrophy and gastric cancer in a country with high Helicobacter pylori infection prevalence

Polarized immune response to Helicobacter pylori and induction of chronic inflammation may increase the risk of gastric atrophy and adenocarcinoma. We studied the association of the response of IgG1 and IgG2 antibodies to H. pylori with grade of gastric chronic inflammation and atrophy in a population with a high prevalence of H. pylori, and compared these data with the data obtained from the study of gastric cancer patients, as well as with the data for CagA positivity. Altogether, 114 persons from two adult population samples from Estonia and 45 consecutive gastric cancer patients were studied. All patients were positive for the H. pylori antibody determined by ELISA. Adenocarcinoma was classified histologically according to the Laurén's system. The response of the IgG subclasses to H. pylori (acid glycine-extracted whole cell proteins) was determined by ELISA and the results were compared with the ELISA results for the recombinant fragment of the CagA protein. Helicobacter pylori IgG level was lower in atrophic gastritis compared with nonatrophic gastritis (chronic inflammation) (p=0.001). In the group of cancer patients, the response of IgG and IgG1 was lower compared with both gastritis groups (p=0.01 and p=0.0002 for IgG, and p=0.001 and p=0.0005 for IgG1). IgG2 was lower for gastric cancer localized in the corpus (p=0.03). In conclusion, atrophic gastritis and gastric cancer were associated with a significant decline in IgG and IgG1 response to H. pylori compared with nonatrophic gastritis. Higher value of CagA antibodies was seen in gastric cancer and in gastric atrophy compared with nonatrophic gastritis; in gastric cancer patients, IgG1 response to H. pylori was correlated with CagA status.     

Improvement of gastric inflammation and resolution of epithelial damage one year after eradication of Helicobacter pylori.

AIMS--To investigate the effect of eradication of Helicobacter pylori infection on gastric epithelial damage and gastritis, scored according to the Sydney system. METHODS--Gastritis scores and epithelial damage were assessed in gastric biopsy specimens before, and five weeks and one year after anti-H pylori therapy in 66 patients with H pylori related gastritis. RESULTS--The mean initial levels of activity, inflammation, atrophy, intestinal metaplasia, and H pylori scores were higher in the antrum than in the corpus or fundus. Eradication of H pylori resulted in an improvement in the mean inflammatory score in antral biopsy specimens from 2.23 before treatment to 1.32 and 1.06, respectively, five weeks and one year after treatment. Corresponding values for fundic biopsy specimens were 1.30, 0.36 and 0.35. Activity scores improved from 1.41 before treatment to 0.13 and zero, respectively, five weeks and one year after treatment in antral biopsy specimens and from 0.60 before treatment to zero in fundic biopsy specimens. Before treatment, epithelial damage was present in 51% of biopsy specimens taken from the antrum and 23% of those from the corpus. Five weeks after eradication of H pylori none of the biopsy specimens revealed evidence of epithelial damage. CONCLUSION--Eradication of H pylori is followed by a rapid, significant improvement in the gastritis score and resolution of epithelial damage in antral and fundic mucosa.     

Spontaneous disappearance of Helicobacter pylori antibodies in patients with advanced atrophic corpus gastritis

Background. Only a few reported studies focus on the natural history and course of advanced and severe chronic atrophic gastritis. Methods. In this study we followed 47 men (mean age 62 years) with advanced (moderate or severe) Helicobacter pylori-positive atrophic corpus gastritis. Duration of endoscopic follow-up was 6 years and follow-up based on serum levels of pepsinogen I and antibodies to H. pylori covered a period of 10 years. None of the patients was treated for H. pylori infection prior to end of follow-up. Results. The median H. pylori antibody titre declined (IgG from 4000 to 1300; IgA from 200 to 50) in the study population, and 11 men (23%) converted to seronegative (p=0.0005, Fisher's exact test). There was a small but significant (p=0.0004, Page's test) declining trend in mean atrophy score of the corpus during follow-up (from 2.5 to 2.2). However, no significant changes were observed in grade of atrophy or intestinal metaplasia of the antral mucosa or in grade of intestinal metaplasia in the corpus. The mean SPGI level remained at the initial low level during the entire follow-up. Conclusions. H. pylori antibodies disappear spontaneously within 10 years in almost one fourth of patients with advanced atrophic corpus gastritis. The disappearance of H. pylori antibodies is accompanied by no or more than a mild improvement of the gastric mucosa.     

Ausmaß, Topographie und Erscheinungsmuster der Helicobacter-pylori-Gastritis Phänotypisierung zur zielgerichteten Diagnose und Therapie?

Helicobacter pylori gastritis, a very common condition, may lead to serious sequelae such as peptic ulcer, gastric carcinoma, and mucosa-associated lymphoid tissue lymphoma. Histological grading of the various gastritis parameters can help to identify the risk of these sequelae and thus improve the indication for prophylactic treatment of the H. pylori infection. This applies in particular to two types of "risk gastritis": gastritis of the duodenal ulcer phenotype and gastritis of the carcinoma phenotype. In the former the antrum shows pronounced inflammatory changes while only low-grade gastritis is seen in the corpus. In the latter, by contrast, the gastritis in the corpus is at least equally as severe as that in the antrum; in addition, intestinal metaplasia and focal atrophy is also frequently found in this phenotype. By establishing topographic grading of the gastritis in antrum and corpus the pathologist can therefore play the role of a "litmus test" for prophylactic H. pylori eradication treatment.     

Expression of Lewis antigens and their precursors in gastric mucosa: relationship with Helicobacter pylori infection and gastric carcinogenesis

Lewis (Le)-associated antigens are carbohydrates that are related biochemically to the ABO blood groups, and may have a role in Helicobacter pylori adherence. To evaluate their relationship to clinicopathological outcomes, gastric Le expression, including type 1 precursor, type 1 H, Le(a), Le(b), Le(x), Le(y) and sialylated Le(a) (CA19-9), was evaluated immunohistochemically in 233 gastric biopsy specimens obtained at routine gastroscopy. Expression was also investigated in gastric tissues showing chronic gastritis, intestinal metaplasia, and carcinoma from 42 patients with gastric cancer. A polymerase chain reaction was performed for H. pylori and the bacterial babA2 gene. We identified type 1 precursor expression in 34.3%, type 1 H in 55.8%, Le(a) in 44.2%, Le(b) in 82.0%, Le(x) in 44.2%, Le(y) 56.7%, and CA19-9 in 16.3% of the 233 gastric biopsy specimens. Expression of type 1 H, Le(b), and CA19-9 was significantly associated with H. pylori infection and histological features (p < 0.05), and expression of type 1 H was an independent predictive factor for H. pylori infection by multivariate logistic regression (p = 0.020). Positivity for the babA2 genotype correlated significantly with H. pylori infection and type 1 H expression in gastric biopsy specimens (p < 0.05). The babA2 genotype was more frequent in gastric mucosa from the gastric cancer patients than in gastric biopsy specimens from routine gastroscopy (p = 0.009). In the 42 gastric cancer patients, the frequency of type 1 precursor, Le(a), and Le(x) expression was significantly higher in intestinal metaplasia and carcinoma than in chronic gastritis (p < 0.05), but the frequency of type 1 H and Le(b) expression was significantly lower in intestinal metaplasia and carcinoma (p < 0.05). In conclusion, Le expression, especially that of type 1 H, was significantly associated with clinicopathological features. In gastric cancer patients, Le expression was altered in intestinal metaplasia and carcinoma in comparison with chronic gastritis.     

In patients with Helicobacter pylori gastritis and functional dyspepsia, a biopsy from the incisura angularis provides useful diagnostic information

The aim of this study was to assess whether the taking of an additional biopsy from the incisura angularis increases the chance of detecting maximal degrees of atrophy and intestinal metaplasia (IM) in patients with Helicobacter pylori gastritis and functional dyspepsia. At entry into a randomised trial, biopsies were taken from 328 patients (mean age 48 years), two from both the gastric antrum and corpus, and one from the incisura angularis, and comparative grading of gastritis variables was carried out. Biopsy material from the gastric antrum, corpus, and the incisura angularis revealed no notable differences in atrophy or an incidence of IM and mucosa-associated lymphatic tissue. However, when the incisura biopsies were classified histologically, 58% contained antral mucosa (AM), 18% corpus mucosa (CM), and 24% intermediate zone mucosa. AM at the incisura was associated with considerably more severe gastritis in both the incisura and antrum (14% atrophy, 20% IM) than in CM of incisura (2% atrophy, 6% IM). Corpus atrophy and IM were rare in the AM group and absent from the CM group. Incisura angularis biopsy in patients with H. pylori gastritis and functional dyspepsia does give additional information regarding the severity of gastritis expected in the corpus and antrum. Antral-type mucosa in the incisura angularis region seems to indicate an increased risk for the development of atrophy and/or IM.     

Clinical, endoscopic and histologic aspects of chronic Helicobacter pylori gastritis in Côte d'Ivoire: study of 102 patients

BACKGROUND: Helicobacter pylori (H. pylori) is the most frequent aetiological factor of chronic gastritis (CG). The relationship between H. pylori gastritis, gastro-duodenal ulcer and some gastric cancers (adenocarcinoma, gastric MALT lymphoma) has now been proven. AIM: Describe clinical, endoscopical and histological aspects of H. pylori gastritis in C?te d'Ivoire. METHODS: Retrospective analysis of 1960 gastroscopy reports carry out between January 1994 and December 1995. Analysis of clinical and gastric histological results in 137 patients. FINDINGS: Among 137 patients with gastric biopsy, 102 had H. pylori gastritis (68 men, 38 women, mean age: 39.3 years) and 35 had chemical gastritis. Epigastric pain was the most frequent symptom. The mucosa was frequently erythematous or exsudative at endoscopy. Histological anomalies were located in the antrum, the fundus or generalised, respectively in 33.3%, 25.5% and 41.2% of cases. Mild atrophic CG was more frequent in various locations. Gastritis activity was present in 81.4%, intestinal metaplasia in 18.6% and follicular lymphoid hyperplasia in 36.3% of cases. CONCLUSION: Clinical and endoscopical aspects of H. pylori gastritis did not present any particularities. Fundic gastritis without antral localisation was not unusual. This situation could be the result of antibiotic and gastric acid secretion inhibitor treatments.     

Alterations in the proliferating compartment of gastric mucosa during Helicobacter pylori infection: the putative role of epithelial cells expressing p27(kip1).

The proliferating zone contains stem cells that give rise to all epithelial cells of the gastric mucosa. In the present study, we investigated the turnover of gastric epithelial cells in the proliferating zone of Helicobacter pylori-infected mucosa, with or without intestinal metaplasia, before and after eradication of the microorganism. In addition, we studied the topographical distribution of the cyclin dependent kinase inhibitor p27(Kip1), which plays a critical role in cell cycle progression and differentiation programs. Twenty-eight patients (22 male), aged 32-78 years and with dyspeptic symptoms, were endoscoped, and gastric biopsies were obtained from antrum and corpus for histopathological examination and the Campylobacter-like organisms test; eradication therapy was given to infected patients, and all patients were re-endoscoped after 105 +/- 33 days (mean +/- SD). The kinetics of gastric epithelial cells and p27(Kip1) status was assessed by means of immunohistochemistry and TUNEL (Tdt-mediated dUTP-biotin nick end labeling) assay. Twenty-one (21) of 28 patients were H. pylori positive, and 7 were found H. pylori negative and served as controls. In antrum, intestinal metaplasia was detected in 7/21 (33.3%). In H. pylori gastritis, Ki67 expression was found increased in the proliferating zone, compared with normal (P =.03); analogous results were obtained with the other proliferation markers, namely retinoblastoma protein and topoisomerase IIalpha. An inverse relationship between proliferation index and atrophy was disclosed (P =.02). A reduction in the proliferation index was observed after eradication, albeit not significant. Apoptotic epithelial cells were found significantly increased (P <.01) in H. pylori gastritis, and a significant reduction was observed after eradication (P <.01). In addition, apoptotic index was found to correlate with H. pylori density. The topographical study of p27(Kip1) revealed a p27(kip1)-positive epithelial cell population that resided deep in the proliferating zone; these cells were considered to be stem cells and were found significantly increased in areas with intestinal metaplasia (P <.05); in H. pylori gastritis, there was also an increase that did not reach statistical significance. H. pylori infection induces apoptosis and increases proliferation in the proliferating zone. The increased cellular turnover, together with the increased number of putative p27(Kip1)-positive stem cells in the context of intestinal metaplasia, provides further evidence for the role of H. pylori infection in gastric carcinogenesis.