Prevalence of Helicobacter pylori infection and gastric cancer precursor lesions in patients with dyspepsia

BACKGROUND: Helicobacter pylori infection has been considered to play significant role in gastric carcinogenesis, but only a minority of people who harbor this organism will develop gastric cancer. H. pylori infection first causes chronic non atrophic gastritis. Chronic non atrophic gastritis may evolve to atrophic gastritis and intestinal metaplasia and finally to dysplasia and adenocarcinoma. AIMS: To estimate the prevalence of H. pylori infection and the precancerous gastric lesions and their relationship, in patients with dyspeptic symptoms who underwent upper gastrointestinal endoscopy at a reference center in the central region of Rio Grande do Sul state, Brazil. METHODS: We analyzed gastric biopsies taken from corpus and antrum of patients who underwent upper gastrointestinal endoscopy for H. pylori detection, between 1994 and 2003. According to Sydney system, chronic non atrophic gastritis, atrophic gastritis and intestinal metaplasia were diagnosed by histological examination (H-E stain). The histological diagnoses were related to H. pylori infection status. RESULTS: Biopsies from 2,019 patients were included in the study. Patients mean age was 52 (+/-15) and 59% were female. Seventy six percent had H. pylori infection. Normal mucosa, chronic non atrophic gastritis, atrophic gastritis and intestinal metaplasia were diagnosed in 5%, 77%, 3% and 15%, respectively. The OR for any degree of gastric mucosa lesion in infected patients was 10 (CI95% 6.50 - 17%). The OR for infected patients had chronic non atrophic gastritis was 3 (CI95% 2,2 - 3,4). The OR for infected patients had atrophic gastritis or intestinal metaplasia was less than 1. CONCLUSIONS: The prevalence of H. pylori infection in this population was high (76%) and infected individuals had the probability 10 folds greater than non infected individuals to have any lesion of gastric mucosa. The prevalence of precancerous lesions was 77% for non atrophic chronic gastritis, 3% for atrophic gastritis and 15% for intestinal metaplasia. Infected patients had risk 3 folds greater than non-infected for the occurrence of non atrophic chronic gastritis. H. pylori infection did not show risk for occurrence of atrophic gastritis and intestinal metaplasia, suggesting that other risk factors should be involved in the carcinogenesis process.     

Can gastric cancer be prevented by Helicobacter pylori eradication?

Helicobacter pylori infection always causes chronic gastritis and triggers several gastroduodenal pathologies ranging from peptic ulcer disease to gastric cancer. It is well established that H. pylori eradication decreases the incidence of gastroduodenal ulcer and its recurrence. However, despite being accepted as the critical risk factor for gastric cancer, there is no conclusive evidence that H. pylori eradication decreases the incidence of gastric cancer. Bacterial virulence characteristics, as well as genetic predisposition of the host in conjunction with certain environmental conditions, are the major factors which influence the development of gastric cancer. Preclinical and clinical data suggest that reversibility of precancerous lesions (atrophic gastritis and intestinal metaplasia) is possible in some patients after H. pylori eradication. Since neoplastic lesions do not progress - or even regress in some cases - after H. pylori eradication, eradication therapy should be considered even in patients with precancerous lesions. Nonetheless, progression of atrophic gastritis and intestinal metaplasia into cancer has been also demonstrated in patients after H. pylori eradication, suggesting that there might be a point of no return where genetic changes have already happened and are irreversible despite elimination of the triggering carcinogen (H. pylori). At the present time the clinical decision to treat a patient is based on established risk profiles. A general screen-and-treat policy, although desirable, currently awaits a less complex treatment regimen.     

Multifocal atrophic gastritis and gastric carcinoma

Gastric carcinoma remains a major cause of morbidity and mortality worldwide despite its significant decline in recent years. H. pylori infection begins with nonatrophic gastritis, and most individuals continue to have nonatrophic H. pylori gastritis throughout their lifetime. A minority of those with severe antral inflammation will develop a duodenal ulcer, and a few, for unknown reasons, may develop gastric MALT lymphoma. Others, who acquired the H. pylori infection in early childhood, develop progressive multifocal atrophic gastritis with loss of gastric glands. A small proportion of these individuals develop extensive, incomplete (type III) intestinal metaplasia, and an even smaller proportion will progress to dysplasia and intestinal-type gastric carcinoma. H. pylori-associated gastritis is also a risk factor for diffuse-type gastric carcinoma, which is not preceded by atrophy, intestinal metaplasia, or dysplasia. Appropriate screening and preventive measures should be considered in high-risk groups. It is also crucial to identify cofactors such as genetic susceptibility and environmental factors that might interact with H. pylori infection to increase gastric cancer risk. To make an impact on gastric cancer incidence and mortality, serious consideration should be given to early H. pylori eradication in high-risk groups and endoscopic surveillance according to the updated Sydney system in some patients with high-risk preneoplastic lesions, whereas dysplastic lesions should be removed without delay. Studies currently in progress may tell us whether H. pylori eradication can prevent later development of gastric carcinoma and thus eliminate a major cause of mortality worldwide.     

Histological changes of gastric atrophy and intestinal metaplasia after Helicobacter pylori eradication]

BACKGROUND/AIMS: Long-term Helicobater pylori infection results in atrophic gastritis and intestinal metaplasia, and increases the risk of gastric cancer. However, it is still controversial that eradication of H. pylori improves atrophy or metaplasia. Therefore, we investigated histological changes after the H. pylori eradication in patients with atrophy or metaplasia. METHODS: One hundred seven patients who received successful eradication of H. pylori infection in Hanyang University, Guri Hospital from March 2001 to April 2006, were enrolled. Antral biopsy was taken before the eradication to confirm the H. pylori infection and grade of atrophy or metaplasia by updated Sydney System. After a certain period of time, antral biopsy was repeatedly taken to confirm the eradication and investigate histological changes of atrophy or metaplasia. RESULTS: Mean age of the patients was 55.3+/-11.3, and average follow-up period was 28.7+/-13.9 months. Endoscopic diagnosis included gastric ulcer, duodenal ulcer, non-ulcer antral gastritis. Atrophy was observed in 41 of 91 and their average score was 0.73+/-0.92. After the eradication of H. pylori, atrophy was improved (0.38+/-0.70, p=0.025). However, metaplasia which was observed in 49 of 107, did not significantly improve during the follow-up period. Newly developed atrophy (7 of 38) or metaplasia (18 of 49) was observed in patients who without atrophy or metaplasia initially. Their average scores were slightly lower than those of cases with pre-existing atrophy or metaplasia without statistical significance. CONCLUSIONS: After the eradication of H. pylori infection, atrophic gastritis may be improved, but change of intestinal metaplasia is milder and may take longer duration for improvement.     

Future candidates for indications of Helicobacter pylori eradication: Do the indications need to be revised?

Since the discovery of Helicobacter pylori in 1982, the development of several treatment guidelines has allowed a consensus on the indications for H. pylori eradication. Beyond these currently accepted indications, including various upper gastrointestinal disorders and extragastric diseases, a significant amount of new information regarding H. pylori eradication is emerging. Certain types of acute gastritis, such as nodular gastritis, hypertrophic gastritis, Ménétrier's disease, hemorrhagic gastritis, and granulomatous gastritis are reversible after H. pylori eradication. Further, for chronic gastritis, closed-type atrophic gastritis and complete-type intestinal metaplasia appear to be more reversible after H. pylori eradication than open-type atrophic gastritis and incomplete-type intestinal metaplasia. Eradication can also be considered in subjects younger than 40 years who have a family history of gastric cancer and in subjects with long-term medications that might lead to bleeding (antiplatelet agents) or atrophy (proton pump inhibitors). Emerging evidence indicates that H. pylori eradication could be an effective treatment for some extragastric diseases that are unresponsive to conventional therapy. In such conditions, routine screening for eradication of H. pylori has not previously been recommended; a "test-and-treat" approach is suggested in the aforementioned situations. Given that H. pylori eradication is effective when the gastritis is reversible, future indications should be expanded to include acute gastric lesions that show marked improvement upon H. pylori eradication rather than just focusing on chronic gastric lesions. Future indications for H. pylori eradication should focus more on reversible lesions before preneoplastic conditions develop.     

Expression of gastric cancer—associated MG7 antigen in gastric cancer,precancerous lesions and H.pylori—associated gastric diseases

AIM: To investigate the relationship between the antigen MG7 antigen expression and gastric cancer as well as precancerous condition; to study the relationship between the MG7 antigen expression and H. pyloriinfection in benign gastric lesions in order to find out the effect of H. pylori infection on the process of gastric cancer development.METHODS: The level of MG7 antigen expression was determined by immunohistochemical method in 383 gastric biopsied materials. The intestinal metaplasia was determined by histochemistry method. The H. pyloriinfection was determined by HE stain, PCR and ELISA in 291 specimens, among which only 34 cases of H. pylori-associated gastric lesions were followed up.RESULTS: The positive rate of MG7 expression in normal gastric mucosa, intestinal metaplasia, dysplasia and gastric cancer increased gradually in ascending order (P＜0.01). The positive rate of MG7 antigen expression in type Ⅲ intestinal metaplasia of gastric mucosa was higher than that of type Ⅰand Ⅱ intestinal metaplasia, being highly significant (P＜0.05).The positive rate of MG7 antigen expression in superficial gastritis, atrophic gastritis and gastric cancer increased gradually (11.9 %, 64.8 %, 91.2 %, P＜0.01). There was no significant difference between H.pylori-negative and H. pyloripositive intestinal metaplasia, atrophic gastritis and dysplasia of gastric epithelium in the positive rate of MG7 antigen expression. There was no expression of MG7 antigen in H. pylori-negative superficial gastritis. The positive rate of MG7 expression in H. pylori-positive superficial gastritis was 20.5 %, and the difference between them was significant (P＜0.05). During following up, one of the three H. pylori negative cases turned positive again, and its MG7 antigen expression turned to be stronger correspondingly. 3 of 31 H. pyloripositive cases were detected as early gastric cancer, among which one with "+++" MG7 antigen expression was diminished after H. pylori eradication.CONCLUSION: MG7 antigen expression is highly specific in gastric cancer and can be used as a good marker for screening of gastric cancer; type Ⅲ intestinal metaplasia, atrophic gastritis and dysplasia should be followed up and MG7 antigen expression has high clinical value in the dynamic follow-up study; although the positive -MG7 in positiveH. pylorisuperficial gastritis show benign morphology in features, there is still the potential risk of developing into gastric cancer, hence special attention should be paid to those showing increasing MG7 antigen expression.     

Helicobacter pylori gastritis in Africa

* Helicobacter pylori gastritis progresses to gland loss and intestinal metaplasia in a considerable proportion of colonized subjects. * The progression to atrophic gastritis is a slow process, occurring with an incidence of 1-2% per year. * The progression of chronic H. pylori gastritis is the same in Africa as in Europe and South America. * This supports the concept of H. pylori as a causative factor of pre-neoplastic conditions of the gastric mucosa; other factors must play a modulating role in the progression to cancer. H. pylori gastritis may progress to atrophic gastritis and lead to the development of intestinal metaplasia, dysplasia and eventually gastric cancer in a minority of subjects. The available data on the kinetics of H. pylori gastritis are limited, but nevertheless very consistent. They suggest that the progression to gland loss or atrophic gastritis among H. pylori-positive subjects occurs at a rate of 1-2% per year. As H. pylori gastritis usually persists for life, a considerable proportion of H. pylori-positive subjects thus eventually show signs of gastric gland loss. The majority of these subjects progress to intestinal metaplasia. Despite these consistent findings in different areas of the world, the incidence of gastric cancer is only moderately related to the prevalence of H. pylori. An example is the so-called African enigma, referring to a low incidence of gastric cancer in certain countries of Africa, despite a high prevalence of H. pylori in all age groups. This is not due to differences in progression to atrophic gastritis; other yet unidentified factors therefore must play a role.     

Aging increases, and duodenal ulcer reduces the risk for intestinal metaplasia of the gastric corpus in Japanese patients with dyspepsia

BACKGROUND AND AIMS: The classification of gastritis by using the revised Sydney system suggests that there are two types of Helicobacter pylori-related gastritis. The aim of the present study was to examine the risk factors that might be involved in the presence of either atrophic gastritis or intestinal metaplasia of the gastric corpus of Japanese patients. METHODS: Biopsy samples were obtained from the gastric corpus in 154 patients with dyspepsia, and the degree of atrophy or intestinal metaplasia was determined histologically. The correlation between several variables and presence of atrophy or intestinal metaplasia was evaluated by using multivariate analysis. RESULTS: Among the 11 variables, which included age, peptic ulcer diseases and H. pylori infection, H. pylori infection was the major risk factor associated with the presence of atrophic gastritis or intestinal metaplasia of the gastric corpus. In contrast, duodenal ulcer (DU) disease reduced the risk of contracting both conditions. Age was an independent risk factor only for intestinal metaplasia of the gastric corpus. When 128 H. pylori-positive subjects were analyzed, DU and age were similarly associated with the presence of both conditions. CONCLUSIONS: These results suggest that DU reduces the risk for contracting atrophic gastritis and intestinal metaplasia, and age is an independent risk factor for intestinal metaplasia of the gastric corpus in dyspeptic Japanese patients.     

Prevention by bovine milk against Helicobacter pylori-associated atrophic gastritis through its adherence inhibition

BACKGROUND/AIMS: The effects of Helicobacter pylori infection on the development of atrophic gastritis and intestinal metaplasia in relation to lifestyle and diet and the effect of the bovine milk on H. pylori adherence to gastric antral mucosa were investigated. METHODOLOGY: H. pylori infection was investigated in 63 patients without endoscopic evidence of gastroduodenal disease. Presence of H. pylori infection was assessed by culture and histologic examination of antral and corpus biopsy samples. Grades of atrophic gastritis and intestinal metaplasia were judged with chromoendoscopy (Congo red-methylene blue test). Adherence of H. pylori was evaluated with scanning electron microscopic examination of antral mucosa in Mongolian gerbils. RESULTS: Cross-sectional analysis of lifestyle and diet showed that a high intake of bovine milk was significantly related to prevention of H. pylori infection and the developments of atrophic gastritis and intestinal metaplasia. H. pylori adherence to the gastric mucosa was inhibited by bovine milk in a dose-dependent manner. CONCLUSIONS: Bovine milk prevents the development of atrophic gastritis and intestinal metaplasia through its defense mechanisms against the attachment of H. pylori to the gastric mucosa.     

Hp相关性胃疾病与胃肠化生、不典型增生的关系

目的探讨Hp感染与肠化生、不典型增生等胃癌前期病变的关系.方法693例胃病患者,分慢性浅表性胃炎(CSG)、慢性萎缩性胃炎(CAG)、胃溃疡(GU)及十二指球部溃疡(DU)等四组,胃镜下观察粘膜病变、溃疡部位及性质,胃镜下取材,常规HE染色后观察组织学改变、Giemsa染色后观察Hp感染程度,统计分析Hp感染与肠化生、不典型增生等的关系.结果四组胃疾病中,Hp感染程度与肠化尘程度差异显著(P＜0.01),DU组的Hp感染率高于其它组(P＜0.01),CAG组的胃肠化生率最高(P＜0.05);Hp阳性标本中,CAG组的胃肠化及不典型增生最高(P＜0.01)Hp阴性标本中,CAG组的胃肠本的胃肠化和不典型增生发生率与Hp阴性标本的发生率有显著差异(P＜0.05).结论Hp与CAG并存时,癌前病变发生率最高,其次为GU;建议在临床上,抗Hp治疗和对CAG、GU的治疗同时进行,并内镜随访.     

根除幽门螺杆菌在预防胃癌中的作用

胃癌在全球恶性肿瘤致死亡的原因中位居第二位,幽门螺杆菌（H．pylori）感染是胃癌发生的重要病因。动物研究显示根除H.pylori,特别是在早期阶段,能有效预防胃癌的发生。部分病例通过根除npylori可阻止胃癌前病变的发展并可能使其逆转。最新研究表明根除H．pylori可降低胃癌发生的风险,对无萎缩或肠化生者可能尤其有效。本文就根除H．p）tori在预防胃癌中作用的研究进展作一综述。     

Effect of Helicobacter pylori infection and its eradication on cell proliferation, DNA status, and oncogene expression in patients with chronic gastritis.

BACKGROUND: Helicobacter pylori, the main cause of chronic gastritis, is a class I gastric carcinogen. Chronic gastritis progresses to cancer through atrophy, metaplasia, and dysplasia. Precancerous phenotypic expression is generally associated with acquired genomic instability. AIM: To evaluate the effect of H pylori infection and its eradication on gastric histology, cell proliferation, DNA status, and oncogene expression. METHODS/SUBJECTS: Morphometric and immunohistochemical techniques were used to examine gastric mucosal biopsy specimens from eight controls, 10 patients with H pylori negative chronic gastritis, 53 with H pylori positive chronic gastritis, and 11 with gastric cancer. RESULTS: All patients with chronic gastritis were in a hyperproliferative state related to mucosal inflammation, regardless of H pylori infection. Atrophy was present in three of 10 patients with H pylori negative chronic gastritis and in 26 of 53 with H pylori positive chronic gastritis, associated in 18 with intestinal metaplasia. DNA content was abnormal in only 11 patients with atrophy and H pylori infection; eight of these also had c-Myc expression, associated in six cases with p53 expression. Fifty three patients with H pylori positive chronic gastritis were monitored for 12 months after antibiotic treatment: three dropped out; infection was eradicated in 45, in whom cell proliferation decreased in parallel with the reduction in gastritis activity; atrophy previously detected in 21/45 disappeared in five, regressed from moderate to mild in nine, and remained unchanged in seven; complete metaplasia disappeared in 4/14, and markers of genomic instability disappeared where previously present. In the five patients in whom H pylori persisted, atrophy, metaplasia, dysplasia, and markers of genomic instability remained unchanged. CONCLUSIONS: Chronic H pylori infection seems to be responsible for genomic instability in a subset of cases of H pylori positive chronic atrophic gastritis; eradication of H pylori infection can reverse inflammation and the related atrophy, metaplasia, and genomic instability.     

Effects of Helicobacterpylori eradication on atrophic gastritis and intestinal metaplasia： A 3-year follow-up study

AIM: To investigate the effect of H pylori eradication on atrophic gastritis and intestinal metaplasia (IM). METHODS: Two hundred and fifty-nine patients with atrophic gastritis in the antrum were included in the study, 154 patients were selected for H pylori eradication therapy and the remaining 105 patients served as untreated group. Gastroscopy and biopsies were performed both at the beginning and at the end of a 3-year follow-up study. Gastritis was graded according to the updated Sydney system. RESULTS: One hundred and seventy-nine patients completed the follow-up, 92 of them received H pylori eradication therapy and the remaining 87 H pylori-infected patients were in the untreated group. Chronic gastritis, active gastritis and the grade of atrophy significantly decreased in H pylori eradication group (P<0.01). However, the grade of IM increased in H pylori -infected group (P<0.05). CONCLUSION: H pylori eradication may improve gastric mucosal inflammation, atrophy and prevent the progression of IM.     

Atrophy, metaplasia and dysplasia: are they reversible?

The eradication of Helicobacter pylori results in the decrease and eventual disappearance of inflammation in the gastric mucosa. An important question with practical implications is whether treatment of H. pylori can promote the resolution of atrophy and intestinal metaplasia. If this happens, then one could infer that even in the presence of established multifocal atrophic gastritis the cure of Helicobacter pylori could reduce the risk of developing gastric cancer. Several investigators have addressed the issue, but the cumulative results remain inconclusive. The great latitude that there exists in the interpretation of the concept of atrophy and the patchy distribution of both atrophic changes and intestinal metaplasia (with resulting inevitable sampling error) are important reasons for the wide discrepancy in the conclusions reached by different authors. Controlled, long-term prospective studies conducted in different ethnic and geographic settings are needed to provide sound evidence-based answers to the question of reversibility of atrophy, intestinal metaplasia, and epithelial dysplasia.     

Helicobacter pylori-induced inflammation masks the underlying presence of low-grade dysplasia on gastric lesions

BACKGROUND Helicobacter pylori(H. pylori) infection has been associated with a long-term risk of precancerous gastric conditions(PGC) even after H. pylori eradication.AIM To investigate the efficacy of High-Resolution White-Light Endoscopy with Narrow-Band Imaging in detecting PGC, before/after H. pylori eradication.METHODS We studied 85 consecutive patients with H. pylori-related gastritis with/without PGC before and 6 mo after proven H. pylori eradication. Kimura-Takemoto modified and endoscopic grading of gastric intestinal metaplasia classifications, were applied to assess the endoscopic extension of atrophy and intestinal metaplasia. The histological result was considered to be the gold standard. The Sydney System, the Operative-Link on Gastritis-Assessment, and the OperativeLink on Gastric-Intestinal Metaplasia were used for defining histological gastritis, atrophy and intestinal metaplasia, whereas dysplasia was graded according to World Health Organization classification. Serum anti-parietal cell antibody and anti-intrinsic factor were measured when autoimmune atrophic gastritis was suspected.RESULTS After H. pylori eradication histological signs of mononuclear/polymorphonuclear cell infiltration and Mucosal Associated Lymphoid Tissue-hyperplasia, disappeared or decreased in 100% and 96.5% of patients respectively, whereas the Operative-Link on Gastritis-Assessment and Operative-Link on Gastric-Intestinal Metaplasia stages did not change. Low-Grade Dysplasia prevalence was similar on random biopsies before and after H. pylori eradication(17.6% vs 10.6%, P = 0.19), but increased in patients with visible lesions(0% vs 22.4%, P 0.0001). At a multivariate analysis, the probability for detecting dysplasia after resolution of H. pylori-related active inflammation was higher in patients with regression or reduction of Mucosal Associated Lymphoid Tissue hyperplasia, greater alcohol consumption, and anti-parietal cell antibody and/or anti-intrinsic factor positivity [odds ratio(OR) = 3.88, 95% confidence interval(CI): 1.31-11.49, P = 0.01; OR = 3.10, 95%CI: 1.05-9.12, P = 0.04 and OR = 5.47, 95%CI: 1.33-22.39, P 0.04, respectively].CONCLUSION High-Resolution White-Light Endoscopy with Narrow-Band Imaging allows an accurate diagnosis of Low-Grade Dysplasia on visible lesions after regression of H. pylori-induced chronic gastritis. Patients with an overlap between autoimmune/H. pylori-induced gastritis may require more extensive gastric mapping.     

Diagnosis of Helicobacter pylori infection in patients with atrophic gastritis: comparison of histology, 13C-urea breath test, and serology

BACKGROUND: Atrophic gastritis, a risk factor for gastric cancer, is a late consequence of Helicobacter pylori infection in approximately one-third of the infected patients. It has been suggested that gastric cancer would develop less frequently if H. pylori were eradicated. However, the prevalence of H. pylori infection may be underestimated in patients with atrophic gastritis and intestinal metaplasia if only biopsy-based diagnostic methods are used. METHODS: We compared histology, 13C-urea breath test (13C-UBT), and serology in H. pylori diagnostics in 50 male patients with atrophic corpus gastritis. RESULTS: H. pylori was detected in 15 (30%) patients by histology and in 14 (28%) by 13C-UBT, whereas increased serum antibody levels indicating H. pylori infection were found in 41 (82%) patients (P < 0.0001 between serology and both histology and 13C-UBT). H. pylori infection was associated with atrophic corpus gastritis in 84% of the present patients (in one patient with normal antibody titres H. pylori was defined histologically). CONCLUSIONS: H. pylori infection would have been missed in most patients with atrophic gastritis without the analysis of H. pylori antibodies. Therefore, in patients with atrophic gastritis, the use of serology is encouraged in diagnosing H. pylori infection.     

Helicobacter pylori associated gastric intestinal metaplasia: Treatment and surveillance

Gastric cancer(GC) is one of the leading causes of cancer related death in the world, particularly in East Asia. According to the Correa's cancer cascade, noncardia GC is usually developed through a series of mucosal changes from non-atrophic gastritis to atrophic gastritis(AG), intestinal metaplasia(IM), dysplasia and adenocarcinoma. Atrophic gastritis and IM are therefore generally considered to be pre-neoplastic gastric lesions. Helicobacter pylori(H. pylori) infection is an important initiating and promoting step of this gastric carcinogenesis cascade. Emerging long-term data showed that eradication of H. pylori reduced the risk of subsequent cancer development. It however remains confusing whether eradication of the bacterium in individuals with pre-neoplastic gastric lesions could regress these changes as well as in preventing cancer. Whilst H. pylori eradication could likely regress AG, the presence of IM may be a point of no return in this cascade. Hence, surveillance by endoscopy may be indicated in those with extensive IM or those with incomplete IM, particularly in populations with high GC risk. The optimal interval and the best tool of surveillance endoscopy remains to be determined in future studies.     

Treatment of Helicobacter pylori and prevention of gastric cancer

Gastric cancer is the second commonest fatal malignancy in the world with a high incidence in China. Helicobacter pylori infection is an important factor in the pathogenesis of gastric cancer. Epidemiological studies have shown a strong causal relationship between H. pylori infection and gastric cancer. Animal studies also show that eradication of H. pylori infection, especially at the early stage, is effective in preventing H. pylori-related gastric carcinogenesis. H. pylori eradication leads to regression and prevents the progression of gastric precancerous lesions, but only in a minority of cases. H. pylori eradication appears to be the most promising approach in gastric cancer prevention. The current available data in human studies showed that H. pylori eradication can reduce the risk of developing gastric cancer and this strategy is more useful in patients without atrophic gastritis or intestinal metaplasia. A longer follow-up and additional studies are needed for better understanding this issue.     

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.     

Association of Helicobacter pylori infection with atrophic gastritis and intestinal metaplasia

AIMS: To evaluate the effect of Helicobacter pylori infection and aging on atrophy and intestinal metaplasia of the gastric mucosa. METHODS: One hundred and sixty-three patients were divided into three age groups and underwent an upper gastrointestinal endoscopy where no esophagitis, peptic ulcers, or malignancies were detected. Two biopsy specimens were obtained from the anterior and posterior walls of the antrum and of the fundus. These were used to evaluate the grade of gastritis, bacterial culture and histologic evidence of H. pylori infection. RESULTS: Helicobacter pylori infection was found to be directly associated with an increased risk of gastritis grade (odds ratio (OR) = 90 (95% CI; 30-270)). An age of 60 years and older along with H. pylori infection was also strongly associated with an increased risk of atrophy (OR = 6.6, (95% CI; 2.9-15.2)); OR = 9.8, (95% CI; 2.7-35.4)), as was intestinal metaplasia of the gastric mucosa (OR = 5.5, (95% CI; 1.7-17.6)); OR = 7.9, (95% CI; 2.8-46.1)). The prevalence of atrophic gastritis increased with advancing age in H. pylori-infected patients, but no such phenomenon was observed in H. pylori-uninfected patients. The prevalence of intestinal metaplasia significantly increased with advancing age, irrespective of the presence of H. pylori infection. In addition, H. pylori uninfected female patients had a decreased risk of intestinal metaplasia. CONCLUSIONS: These results suggest that atrophic gastritis is not a normal aging process, but instead is likely to be the result of H. pylori infection, while intestinal metaplasia is caused by both the aging process and H. pylori infection. A decreased risk of intestinal metaplasia found in uninfected female subjects may partly explain the lower prevalence of gastric cancer in females than in males.