Regression of primary gastric lymphoma of mucosa-associated lymphoid tissue type after cure of Helicobacter pylori infection. MALT Lymphoma Study Group

Outcome in relation to treatment modalities in 48 patients with localized gastric MALT lymphoma: a retrospective study of patients treated during 1976-2001

The aim of this study was to retrospectively analyze survival and tumor response data in patients with localized gastric MALT lymphoma treated by different treatment modalities other than anti-Helicobacter pylori treatment (diagnosis made before 1993, or after failure of antibiotics + anti-acid), including surgery, chemotherapy or combined treatment. Here we studied a series of 48 patients with stage IE or IIE disease treated during the past 11 years. These patients received different treatments: chemotherapy was proposed to 19 (40%) patients; gastric surgery to 21 (43%) patients, consisting of partial gastrectomy of 7 patients and total gastrectomy in 14 patients; combined treatment to 8 (17%) patients, consisting of surgery + chemotherapy in 7 patients and surgery + chemotherapy + radiotherapy in 1 patient. At diagnosis, 85% of the patients had good PS and no B symptoms. Complete response after treatment was reached in 45 (94%) patients (chemotherapy: 84% of the patients; surgery alone: 95%; combined treatment: 100%). Progression was observed in 16 (33%) patients. No statistical difference in the survival was found among the different therapeutic modalities: 5-year overall survival year FFP survival was 81% for chemotherapy, 86% for surgery alone and 95% for combined treatment. Prognostic factors for survival were age, performance status and hemoglobin level at diagnosis. Considering the natural bias of a retrospective analysis, surgery or chemotherapy was associated with a similar outcome in patients with MALT lymphoma after antibiotics failure.

Long-term follow up of gastric low-grade mucosa-associated lymphoid tissue lymphoma by endosonography emphasizing the application of a miniature ultrasound probe

BACKGROUND AND AIMS

Endoscopic ultrasonography (EUS) is a useful tool for the evaluation of gastric wall infiltration including gastric lymphoma. The aims of this study were to characterize gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphoma according to EUS findings and to evaluate the role of a miniature ultrasound probe in the long-term follow up.

METHODS

From January 1994 to March 2002, 20 patients were proven to have gastric low-grade MALT lymphoma. Endoscopic ultrasonography was performed with a conventional echoprobe and/or a miniature ultrasound probe for initial staging and a miniature ultrasound probe was performed during follow up. All patients positive for Helicobacter pylori received a 2-week course of omeprazole, amoxicillin and clarithromycin.

RESULTS

Helicobacter pylori infection was found in 17 (85%) patients. In all patients, H. pylori was eradicated after treatment. Initial EUS showed significantly greater wall thickness (6.1 +/- 3.0 mm) in MALT lymphoma patients when compared with control (2.8 +/- 0.3 mm). The infiltrative patterns included wall thickening (3.5-14.1 mm) in 18 patients: stage E-I1 in 16 (mucosa and/or submucosa), stage E-I2 in one and stage E-II in one. Complete regression of MALT lymphoma following treatment for H. pylori was noted in 14 patients, with a mean duration of 11.3 +/- 9.1 months. Follow-up miniature ultrasound probe sonography showed comparative reduction in wall thickness (P < 0.05).

CONCLUSIONS

Endoscopic ultrasonography plays a valuable role in the initial staging and long-term follow up of gastric low-grade MALT lymphoma. The application of a miniature ultrasound probe enables adequate evaluation in the majority of these patients, with additional benefits.

Which test to use to detect Helicobacter pylori infection in patients with low-grade gastric mucosa-associated lymphoid tissue lymphoma?

Helicobacter pylori is involved in the pathogenesis of lymphoma of the gastric mucosa-associated lymphoid tissue (MALT). Because gastric MALT lymphoma is a rare disease, few studies comparing the accuracy of diagnostic tests in this group of patients have been carried out, and only a limited number of tests (essentially histological) were performed. The aim of our study was to compare the results of four different diagnostic methods used to detect H. pylori (histology, culture, polymerase chain reaction, and serology) in a prospective multicenter study. A patient was considered to be H. pylori positive if culture or histology was positive. During the period 1995-2000, a total of 90 patients with low-grade gastric MALT lymphoma were enrolled. Results for the four tests were available for 56 patients (62.2%). Among these patients, the four tests were concordant in 35 cases (62.5%), i.e., were positive in 19 cases (33.9%) and negative in 16 patients (17.8%). Histology (39/40 positive, 97.5%) and serology (38/40 positive, 95.0%) were the most sensitive tests. Polymerase chain reaction (PCR) and culture were positive in 52.5% and 50%, respectively. The cagA gene was detected in 47.4% of the strains.

Gastric mucosa: long-term outcome after cure of Helicobacter pylori infection

The histopathological changes due to chronic Helicobacter pylori infection are well characterized. Nevertheless, the clinical and pathological outcomes resulting from the cure of this infection remain incompletely described. In particular, the influence of eradication of H. pylori on nonulcer dyspepsia, the long-term effects of H. pylori eradication on gastric atrophy and intestinal metaplasia, and the role of H. pylori eradication in the prevention of gastric cancer are still unclear. We reviewed 38 studies reported between 1993 and 1999 on the outcome of various disorders related to H. pylori infection after successful eradication. There is general agreement concerning the regression of chronic gastritis, lymphoid follicles, and limited-stage low-grade MALT lymphomas of the gastric mucosa after eradication of H. pylori infection. Conversely, there are still major questions on whether H. pylori eradication improves the outcome of premalignant lesions, such as atrophy, intestinal metaplasia, and dysplasia. Finally, some extragastric idiopathic diseases seem to improve in consequence of the eradication of the infection, although there are still no definitive data to support this.

Indications for Helicobacter pylori eradication therapy and first-line therapy regimen in Japan: recommendation by the Japanese Society for Helicobacter Research

In November 2000, eradication therapy for Helicobacter pylori infection was approved under the present Japanese system of health insurance. Before the approval, the Japanese guideline of "Diagnosis and Treatment of H. pylori infection" was made by the guideline committee of the Japanese Society for Helicobacter Research. Indications for H. pylori eradication therapy were classified into three groups: (A) recommended: gastric and duodenal ulcers; (B) recommended and managed at a specialized institution: low-grade gastric mucosa-associated lymphoid tissue lymphoma; (C) current studies of the significance of the therapy: following endoscopic mucosal resection of early gastric cancer and gastric surgery for gastric cancers, hyperplastic gastric polyp, atrophic gastritis, and nonulcer dyspepsia. The first-line therapy regimen recommended is 1 week of triple therapy with a proton pump inhibitor standard dose twice a day, amoxicillin 750 mg bid, and clarithromycin 200 or 400 mg bid. The reasons for preferring this regimen are to avoid extensive use of metronidazole, which is allowed for treatment of Trichomonas infection in Japan, and the low rate of emergence of clarithromycin-resistant H. pylori with amoxicillin co-therapy. For second-line therapy patients should be referred to specialists, who can examine the susceptibility of H. pylori isolates against antibiotics and have much experience with this therapy.

Gastric cancer epidemiology and risk factors

We performed a detailed analysis of the epidemiology of gastric carcinoma, based upon a review of the literature in English. The analysis reveals many puzzling features. There has been a steady fall in the incidence of gastric carcinoma in most societies studied, but a more recent steady rise in the incidence of adenocarcinoma of the cardia and lower esophagus, largely confined to White males. Although the evidence for a major role for Helicobacter pylori (H. pylori) in the etiology of gastric corpus cancer is compelling; in Western society, it probably accounts for fewer than half the cases. The relative roles of dietary constituents such as salt and nitrites and the phenotyping of H. pylori in causation and the beneficial effects of a high fruit and vegetable diet and an affluent lifestyle, for all of which there is some evidence, are yet to be quantified.

The Relationship Between Primary Gastric B-cell Lymphoma and Immunoglobulin Heavy Chain (IgH) Gene Rearrangement – A Histopathological Study of Primary Gastric Lymphomas

The aim of this study was to review our primary gastric lymphoma cases according to the new WHO classifications and to investigate the histopathological features of B-cell lymphomas. In addition, B-cell monoclonality was analyzed for immunoglobulin heavy chain (IgH) gene rearrangement using the polymerase chain reaction at the site of the lymphoma lesion, transitional lesion, and the non-lymphoma lesion. Specimens resected from 31 primary gastric lymphomas were examined. There were 28 cases (90.3%) of B-cell lymphoma and three cases (9.7%) of T-cell lymphoma. The B-cell lymphomas were classified as low-grade mucosa-associated lymphoid tissue (MALT) lymphoma (LGML) (9%), high-grade MALT lymphoma (HGML) (42%), and diffuse large B-cell lymphoma (DLBCL) (29%). Histopathologically, lymphoepithelial lesions (LEL) were higher in LGML (100%) than in DLBCL (22%), with statistical significance (p < 0.05). A monoclonal pattern of IgH rearrangement was detected in LGML (50.0%), HGML (60.0%), and DLBCL (80.6%), with a statistically significant difference between LGML and DLBCL (p < 0.01). The IgH monoclonal pattern may reflect the gross appearance of lymphoma or the lymphoma infiltration depth. Superficial spreading and shallow growth in LGML may correspond to an oligoclonal pattern, and mass-forming and deep invasive growth in DLBCL may correspond to a more monoclonal pattern.

Differentiation of low-grade gastric MALT lymphoma and high-grade gastric MALT lymphoma: the clinical value of Ga-67 citrate scintigraphy--a pilot study

Ga-67 citrate scintigraphy has been routinely and extensively used to evaluate non-Hodgkin's lymphoma (NHL) for more than 20 years. Gastric lymphoma of mucosa-associated lymphoid tissue (MALT) is by far the most common extranodal primary NHL. Gastric MALT lymphoma can be classified as low-grade (LG) or high-grade (HG). Low-grade gastric MALT lymphoma can be cured by eradication of Helicobacter pylori; but radiotherapy and/or chemotherapy and/or surgery are the major methods of treatment for the HG gastric MALT lymphoma. However, it is difficult to differentiate these two groups by clinical parameters and endoscopic findings. The purpose of this study was to determine whether Ga-67 citrate scintigraphy can distinguish the LG gastric MALT lymphoma from the HG gastric MALT lymphoma. Twenty-one patients (11 men and 10 women ranging in age from 38 to 83 years) with histologically confirmed gastric MALT lymphoma were enrolled. Twelve patients had LG and nine patients had HG. All 21 patients underwent Ga-67 citrate scintigraphy before treatment. The results of Ga-67 citrate scintigraphy were classified as positive or negative. In the LG group, nine patients had negative results and three patients had positive results. In the HG group of nine patients, all patients had positive results. Among the three patients who had positive results in the LG group, the uptake of gastric MALT lymphoma was lower than that of the liver. The Ga-67 citrate scintigraphy is of good clinical value for the differentiation of the LG gastric MALT lymphoma and the HG gastric MALT lymphoma. We think that the major value of Ga-67 citrate scintigraphy will be in following the patients with HG gastric MALT lymphoma after treatment to assess response of therapy and to detect possible recurrence and perhaps in determining transformation from the LG to HG gastric MALT lymphoma. However, further investigation is needed to understand the relationship between the uptake of Ga-67 citrate in gastric MALT lymphoma and transformation.

Lymphoid malignancies: the dark side of B-cell differentiation

When the regulation of B-cell differentiation and activation is disrupted, lymphomas and leukaemias can occur. The processes that normally create immunoglobulin diversity might be misdirected, resulting in oncogenic chromosomal translocations that block differentiation, prevent apoptosis and/or promote proliferation. Prolonged or unregulated antigenic stimulation might contribute further to the development and progression of some malignancies. Lymphoid malignancies often resemble normal stages of B-cell differentiation, as shown by molecular techniques such as gene-expression profiling. The similarities and differences between malignant and normal B cells indicate strategies for the treatment of these cancers.

Molecular biology of gastric MALT lymphoma: application in clinical management

The development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma depends critically on Helicobacter pylori infection. The bacterial infection stimulates the lymphoma B-cells through both direct (auto-antigen) and indirect (H. pylori specific intra-tumour T-cells) immunological stimulation. It also promotes the acquisition of genetic abnormality through activated neutrophils, which release oxygen reactive species. Malignant clones bearing t(11;18)(q21;q21) form lymphomas that are H. pylori growth independent. Those without t(11;18)(q21;q21) but with other genetic abnormality such as trisomy 3 depend critically on H. pylori mediated immune response at early stages and are therefore responsive to H. pylori eradication. However, at late stages when additional genetic defects such as t(1;14)(p22;q32) accumulate, the tumour may escape its growth dependence on H. pylori mediated immune response. Detection of these chromosomal translocations has significant implication in clinical management of patients with gastric MALT lymphoma.

Clinicopathological features of gastric B-cell lymphoma: a series of 317 cases

The stomach is a common site of extranodal malignant lymphoma. Here we examined the clinicopathological features of 317 gastric B-cell lymphomas and characterized the differences among low-grade mucosa-associated lymphoid tissue (MALT) lymphomas (LG), high-grade MALT lymphomas (HG), follicular lymphomas (FL) and diffuse large B-cell lymphomas (DL). Cases included 126 DL, 71 HG, 98 LG, 10 FL, three Burkitt's lymphoma and nine of undefined type. The age range of patients was as follows: LG, 14-96 years (mean, 61.1); HG, 20-87 years (mean, 63.9); DL, 16-88 years (mean, 62.8); and FL, 54-76 years (mean, 65.5). There were no differences in age with respect to tumor type. There were more women patients with LG (female:male, 55:43), while males predominated among DL patients (54:72). The sexes were represented almost equally in HG cases (34:37). Histological findings, especially in DL tumors, correlated significantly to the gross appearance of mass formation. Dutcher bodies were encountered mainly in HG or LG cases. Our results showed no differences in age, sex or site of disease between LG, HG and DL tumors. However, the grade of malignancy correlated strongly to gross appearance. Dutcher bodies were important for the diagnosis of gastric MALT lymphoma.

Diagnostic accuracy of EUS in the local staging of primary gastric lymphoma: results of a prospective, multicenter study comparing EUS with histopathologic stage

BACKGROUND

Grade of malignancy and stage of disease are the decisive prognostic factors and therapeutic determinants in primary gastric lymphoma. It is supposed that EUS allows determination of depth of tumor infiltration and perigastric lymph node involvement, thus defining stages I1, I2, and II1. This multicenter study evaluated the accuracy of EUS in the staging of gastric lymphoma.

METHODS

Data from preoperative EUS procedures performed at 34 centers were compared with the histopathologic stage of resection specimens in 80 patients with newly diagnosed primary gastric lymphoma. Ten patients with stage II2 were excluded from analysis because EUS is inappropriate for the evaluation of nonregional lymph node involvement.

RESULTS

EUS correctly classified the lymphoma in 37 of 70 patients (53%). Sensitivity of EUS was as follows: stage I1, 67% (95% CI [38%, 88%]; p = 0.01); stage I2, 83% (95% CI [52%, 98%]; p = 0.01); and stage II1, 71% (95% CI [49%, 87%]; p = 0.02).

CONCLUSION

The accuracy of EUS in the local staging of gastric lymphoma has to be improved if nonsurgical treatment strategies based on the grade of malignancy and stage of the disease are to be used. Because most of the participating centers performed EUS in relatively few patients, no conclusion could be drawn with respect to accuracy in relation to EUS experience available at each center or technical considerations with respect to the types of instruments used.

Gastrointestinal endoscopic ultrasonography

Although conventional endoscopy provides excellent visualization of gastrointestinal mucosa, it provides little information about intramural or nearby extramural lesions. The imaging of intraabdominal structures by conventional transabdominal ultrasound is degraded by ultrasound energy attenuation with distance. The provision of an ultrasound probe on a flexible gastrointestinal endoscope, to form an echoendoscope, provides excellent imaging of the gastrointestinal wall and of adjacent extramural structures. During the last two decades, endoscopic ultrasound, using an echoendoscope, has revolutionized the diagnosis and treatment of gastrointestinal diseases that affect the submucosa, deep bowel wall, and adjacent extramural structures. This article reviews the role of endoscopic ultrasound in the diagnosis and treatment of gastrointestinal disease, including standard and promising new applications, as well as standard and emerging new technology.

Pediatric disorders of the stomach

Disorders of the stomach represent a significant portion of the practice of pediatric gastroenterology. Controversy still exists in the appropriate management of children with abdominal pain and vomiting and large gaps remain in our understanding of the physiology and pathophysiology of the stomach in children. Nevertheless, we have made significant progress in understanding Helicobacter pylori infection and gastric motility in the pediatric population.

Radiographic findings of primary B-cell lymphoma of the stomach: low-grade versus high-grade malignancy in relation to the mucosa-associated lymphoid tissue concept

OBJECTIVE

We undertook this study to assess how well double-contrast radiography and CT allow radiologists to differentiate low-grade from high-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach.

MATERIALS AND METHODS

We retrospectively reviewed the upper gastrointestinal radiographs and contrast-enhanced CT scans of 57 patients with pathologically proven primary gastric lymphoma (low-grade [n = 29] and high-grade [n = 28] MALT lymphoma).

RESULTS

On upper gastrointestinal radiography, ulceration (39%) was the most common finding in low-grade lymphoma, whereas polypoid appearance (38%) was the most common in high-grade lymphoma. In the 29 patients (33 lesions) with low-grade MALT lymphoma, upper gastrointestinal radiography revealed 13 ulcerative lesions (39%), 10 nodular lesions (30%), four infiltrative lesions (12%), two polypoid lesions (6%), and four combined lesions (12%). In the 28 patients (29 lesions) with high-grade lymphoma, upper gastrointestinal radiography revealed 11 polypoid lesions (38%), nine infiltrative lesions (31%), six ulcerative lesions (20%), one nodular lesion (3%), and two combined lesions (7%). On CT, thickening of the gastric wall in low-grade lymphoma (range, 0.3-2.5 cm; mean, 0.8 cm) was much less than that in high-grade lymphoma (range, 0.7-8.0 cm; mean, 2.5 cm). Abdominal lymphadenopathy was less frequent in low-grade lymphoma (14%) than in high-grade lymphoma (75%).

CONCLUSION

Most low-grade lymphomas show superficial spreading lesions, such as mucosal nodularity, shallow ulcer, and minimal fold thickening, on upper gastrointestinal radiography, whereas most high-grade lymphomas show mass-forming lesions or severe fold thickening.

Stool antigen assay (HpSA) is less reliable than urea breath test for post-treatment diagnosis of Helicobacter pylori infection

BACKGROUND

The diagnostic yield of the stool antigen test (HpSA) in evaluating the results of Helicobacter pylori eradication therapy is controversial, but many studies have used only the 13C-urea breath test (13C-UBT) as a gold standard which has greatly reduced their relevance.

AIM

To compare the reliability of HpSA and 13C-UBT in patients post-treatment using biopsy-based methods as reference tests.

METHODS

A total of 100 consecutive dyspeptic patients (42 male and 58 female; mean age, 56 +/- 18 years) were enrolled in our study. All patients were H. pylori positive on the basis of at least two biopsy-based methods, and underwent 1 week of treatment with various triple therapies. They were again endoscoped 4 weeks after completing therapy and six biopsy specimens were taken from the gastric antrum and corpus for rapid urease test, histology and culture. HpSA and 13C-UBT were also performed within 3 days of the second endoscopy.

RESULTS

On the basis of biopsy-based tests, infection was eradicated in 77 patients but continued in 23. Three false negatives were observed with HpSA and two with 13C-UBT. In contrast, the number of false positives was significantly higher (P < 0.01) with HpSA than with 13C-UBT (nine vs. one), confirming the lower specificity of the former test. The overall accuracy of HpSA was 88% vs. 97% for 13C-UBT (P < 0.02).

CONCLUSIONS

HpSA has lower diagnostic value than 13C-UBT in the evaluation of the outcome of anti-H. pylori therapy. 13C-UBT remains the first-line diagnostic method to monitor eradication results. The use of HpSA should be reserved for those settings in which 13C-UBT is not available.

The importance of endoscopic ultrasonography in the management of low-grade gastric mucosa-associated lymphoid tissue lymphoma

BACKGROUND

Anti-Helicobacter pylori therapy has been reported to cause regression of low-grade gastric mucosa-associated lymphoid tissue lymphoma in a high percentage of patients. However, in some patients, these lesions persist despite antibiotic treatment.

AIM

To determine the various endosonographic findings that may predict the regression of low-grade gastric mucosa-associated lymphoid tissue lymphoma post-antibiotics.

METHODS

Seventy-six patients with Helicobacter pylori-positive gastric mucosa-associated lymphoid tissue lymphoma were studied. Follow-up data were available on 51 patients. All patients were treated with antibiotics. Participants underwent pre- and post-anti-Helicobacter pylori therapy endoscopy with gastric biopsies, followed by endoscopic ultrasonography examination of the stomach.

RESULTS

Helicobacter pylori was eradicated in 45 of 51 (88%) patients. At the 2-year follow-up, complete regression of mucosa-associated lymphoid tissue lymphoma was seen in 28 of 51 (55%) patients: 12 of 16 (75%) patients in stage T1m N0, 11 of 19 (58%) patients in stage T1sm N0, four of eight (50%) patients in stages T1m N1 and T1sm N1, and one of four (25%) patients in stage T2 N0. None of the stage T2 N1 patients achieved clinical regression.

CONCLUSIONS

Endoscopic ultrasonography evaluation of gastric mucosa-associated lymphoid tissue lymphoma plays a pivotal role in the initial staging and post-treatment follow-up evaluation of these lesions. Accurate staging is essential in the determination of the optimal treatment modality.

Apoptosis in lymphocytic leukemias and lymphomas

Most current classifications of lymphoid neoplasms define the tumors based on the cell of origin, phenotype, genetic abnormalities, and clinical features. Here it is proposed that human lymphocytic tumors can be categorized based on the propensity and capacity of the tumor cells to undergo apoptosis. The first category is defined by malignant cells that are resistant to apoptosis due to expression of anti-apoptotic factors such as bcl-2 and cellular inhibitors of apoptosis (IAPs). These tumors would include CLL and follicular lymphomas, as well as some malignancies in which the tumor cells are infected by viruses that co-opt cell survival pathways, such as human T-cell leukemia/lymphoma virus (HTLV)-1. The second category, in which the malignant cells are apoptosis-prone, would include tumors arising in the context of impaired cytotoxic T-cell function. These neoplasms would include some human immunodeficiency virus (HIV)-related lymphomas such as Burkitt's lymphoma, and post-transplantation lymphomas. The third category would include neoplasms of intermediate sensitivity to apoptosis, some of which are associated with infection such as mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach. Although this classification is tentative, it should evolve in parallel with our understanding of pathogenic mechanisms in lymphoid neoplasia, and provides a novel framework with which to consider the appropriateness of specific therapeutic strategies. Distinctions among lymphocytic tumors in terms of the likelihood of response to therapies such as antisense to bcl-2 related proteins, inhibitors of NF-kappa B activity, and new approaches aimed at bolstering the host's immune response, would cross standard classifications based on the T or B-cell origin of the tumor cells.

High-grade B-cell lymphoma arising in mucosa-associated lymphoid tissue of the duodenum

Duodenal mucosa-associated lymphoid tissue lymphoma is a rare neoplasm. We report a case of a 70-year-old man with non-Hodgkin's lymphoma located in the descending duodenum that was not associated with Helicobacter pylori infection of the stomach. A surgical resection due to obstruction of the bowel lumen above the ligament of Treitz was performed. No invasion into the adjacent structure was confirmed at surgery. The pathological examination showed an infiltration of the duodenal mucosa and submucosa with B lymphocytes. Monoclonal proliferation of the lymphoid tissue was demonstrated by polymerase chain reaction. The histological appearance and the demonstration of monoclonality fulfilled the criteria for malignant high-grade B-cell lymphoma arising from mucosa-associated lymphoid tissue.

Helicobacter pylori impairs DNA mismatch repair in gastric epithelial cells

BACKGROUND & AIMS

Helicobacter pylori infection is a major gastric cancer risk factor. H. pylori gastritis occurs more frequently in individuals with microsatellite instability-positive than those with microsatellite instability-negative gastric cancers, raising the possibility that H. pylori infection affects DNA mismatch repair (MMR). The aim of this study was to determine the effect of H. pylori on the expression of DNA MMR proteins and RNA in gastric epithelial cells.

METHODS

Gastric cancer cell lines were cocultured with H. pylori, bacterial extracts, and Campylobacter jejuni or Escherichia coli. MutS (hMSH2 and hMSH6) and MutL (hMLH1, hPMS2, and hPMS1) DNA MMR protein and RNA levels were determined.

RESULTS

All cell lines examined showed decreased levels of MutS and MutL DNA MMR proteins in a dose-dependent manner after coculture with H. pylori strains. The reduction in DNA MMR protein levels was caused by heat-sensitive H. pylori products. The levels of DNA MMR proteins were affected by C. jejuni but not by E. coli. RNA levels of hMSH2 and hMSH6 were also reduced after exposure to H. pylori.

CONCLUSIONS

H. pylori infection of gastric epithelial cells leads to a decrease in DNA MMR proteins that is at least in part related to an H. pylori-induced decrease in messenger RNA levels of repair genes. These data suggest that H. pylori infection might lead to a deficiency of DNA MMR in gastric epithelial cells that may increase the risk of mutation accumulation in gastric mucosa cells and the risk of gastric cancer during chronic H. pylori infection.

Chemotherapy for management of localised high-grade gastric B-cell lymphoma: how much is necessary?

BACKGROUND

Recent data suggest that chemotherapy with the cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) regimen is a highly effective treatment for localised primary gastric lymphoma of diffuse large B-cell histology (DLBCL). We have reported that the large majority of patients achieve complete remission (CR) following three cycles of treatment, and now provide an updated series with special emphasis on patients receiving only short-term chemotherapy.

PATIENTS AND METHODS

All patients with a histologically verified diagnosis of gastric DLBCL in stages EI and EII(1) undergoing chemotherapy with the CHOP regimen were evaluated. Data analysed included clinical stage, histology [presence of an additional mucosa-associated lymphoid tissue (MALT) component], evidence of Helicobacter pylori infection, H. pylori eradication, time to CR, survival and regular restaging (i.e. after three and six cycles, respectively).

RESULTS

A total of 37 patients with DLBCL of the stomach with localised disease were identified, five of whom also had a MALT component. Twenty-two patients presented with stage EI and 15 with stage EII(1) disease. All patients were given chemotherapy as sole management of their lymphoma; 36 patients received CHOP, while one patient was given CHOP along with rituximab. Thirty-two (86%) achieved a CR after a maximum of three cycles, while only four patients had to be given six cycles for CR. In total, nine of 37 patients (24%) discontinued therapy earlier than scheduled: one patient received one cycle, two received two, six received three and one patient received four cycles. Two of these patients stopped treatment due to toxicity, i.e. protracted thrombocytopenia or chemotherapy extravasation. One additional patient died after one cycle of treatment; autopsy disclosed no signs of remaining lymphoma. Three patients have died after a median follow-up of 39 months (including the one patient who discontinued therapy after one cycle of treatment), while the remaining 34 patients are alive without evidence of disease. Twenty-four out of 37 patients (65%) had also undergone H. pylori eradication (including six of nine patients receiving only short-term treatment).

CONCLUSIONS

DLBCL of the stomach appears to be a highly chemosensitive disease. Our data question the need for full-term CHOP treatment in patients achieving CR upon first follow-up. However, recent data suggest that additional H. pylori eradication might have contributed to the excellent results achieved in our series.

Helicobacter pylori virulence genes and host IL-1RN and IL-1beta genes interplay in favouring the development of peptic ulcer and intestinal metaplasia

Helicobacter pylori infection outcome might depend on genotypic polymorphisms of both the bacterium and the host. We ascertained: (1) the functionality of H. pylori oipA gene; (2) the polymorphism of the hostinterleukin (IL-1beta) gene (-31 C/T) and of the IL-1RN gene (intron 2 VNTR); (3) the association between the above genes and the histological and pathological outcome of H. pylori infection. One hundred and sixty-five H. pylori positive and 137 H. pylori negative subjects (23 gastric adenocarcinoma, 58 peptic ulcer, 221 gastritis) were studied. oipA was sequenced, IL-1beta was RFLP analysed. Antral and body mucosal biopsies were histologically evaluated. Functional oipA genes were correlated with cagA gene; both genes were significantly associated with gastritis activity, peptic ulcer and gastric adenocarcinoma. In these patients heterozygousIL-1RN 1/2 and IL-1beta C/T genotypes were more frequent than in gastritis patients. Intestinal metaplasia was associated with cagA, functional oipA and IL-1RN 2 allele. In conclusion, peptic ulcer and the preneoplastic intestinal metaplasia are associated with H. pylori virulence genes and with IL-1RN 2 host allele. An interplay between bacterial virulence factors and cytokines genotypes, is probably the main route causing H. pylori infection to lead to benign mild disease, benign severe disease or preneoplastic lesions.

Lymph nodes in gastric B-cell lymphoma: pattern of involvement and early histological changes

AIMS

This study aims to analyse the histological pattern of nodal involvement in gastric B-cell lymphoma and to detect early involvement of the lymph nodes.

METHODS AND RESULTS

Histological findings of 37 resected primary gastric lymphomas with 1313 regional lymph nodes were analysed. The primary tumour was classified into four groups: MALT lymphoma, MALT lymphoma with a minor large B-cell lymphoma (<20%), large B-cell lymphoma with MALT lymphoma, and large B-cell lymphoma without MALT lymphoma. Histological patterns of nodal involvement were divided into sinusoidal, subsinusoidal/marginal, follicular, and diffuse patterns. Semi-nested polymerase chain reaction (PCR) analysis for IgH gene rearrangement was performed. Nodal involvement was found in 2/13 (15%) MALT lymphomas, 5/6 (83%) MALT lymphomas with a minor large B-cell lymphoma, 9/12 (75%) large B-cell lymphomas with MALT lymphoma, and 6/6 (100%) large B-cell lymphomas without MALT lymphoma. The MALT lymphoma and MALT lymphoma with a minor large B-cell lymphoma showed a predominantly sinusoidal and subsinusoidal pattern, whereas diffuse pattern predominated in large B-cell lymphomas without MALT lymphoma and large B-cell lymphomas with MALT lymphoma. The follicular pattern was least common, being observed in 10.2% of large B-cell lymphomas without MALT lymphoma and large B-cell lymphomas with MALT lymphoma. Sinusoidal obliteration with permeation of small monocytoid cells into subsinusoidal zone is a characteristic finding suggesting early nodal involvement of MALT lymphoma.

CONCLUSIONS

Histological patterns of nodal involvement in gastric B-cell lymphoma vary according to the histological grade. Immunostaining for CD20 with or without PCR analysis for IgH gene rearrangement would be a useful ancillary method to confirm lymphomatous involvement.

Interobserver agreement in staging gastric malt lymphoma by EUS

BACKGROUND

EUS is highly accurate for staging gastric lymphoma. Because stage correlates to outcome, interobserver agreement is mandatory. However, previous studies suggest that interobserver agreement might vary according to T-stage. A multicenter evaluation of observer agreement with respect to endosonographic staging of gastric mucosa-associated lymphoid tissue (MALT) lymphoma was therefore conducted.

METHODS

Fifty-four patients were studied; 42 were also evaluated after eradication of Helicobacter pylori infection. EUS was performed at different institutions by 10 experienced endosonographers who collected the best photographs for each examination. Interobserver agreement was estimated with kappa statistics.

RESULTS

Overall interobserver agreement for T-stage was fair, both before and after treatment (kappa = 0.38 and kappa = 0.37, respectively). Overall interobserver agreement for N-stage was substantial before treatment, but only fair after treatment (kappa = 0.63 and kappa = 0.34, respectively). The lowest values of agreement occurred with T1sm (submucosa) and T2 stage lesions.

CONCLUSIONS

Interobserver agreement for staging of gastric MALT lymphoma by EUS is suboptimal before as well as after treatment of H pylori infection. This evidence suggests that gastric EUS may be more difficult technically compared with EUS of other organs. Lack of agreement is crucial because it influences the choice of therapy and assessment of response to treatment. Good interobserver agreement would permit better communication concerning the clinical status of patients, comparison of the results of different studies, and stratification of patients within clinical trials.

Gastric mucosa-associated lymphoid tissue lymphoma: helical CT findings and pathologic correlation

OBJECTIVE

The purpose of this study was to describe helical CT findings of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to correlate them with pathologic findings.

MATERIALS AND METHODS

We retrospectively reviewed CT examinations of 58 patients with confirmed gastric MALT lymphomas. Using the histopathologic grade of the MALT lymphomas, we divided the patients into two groups: those with high-grade lymphoma (n = 21) and those with low-grade lymphoma (n = 37). Common CT findings for the two groups were reviewed and compared.

RESULTS

Forty (69%) of the 58 patients showed at least one abnormality of the stomach on CT. Abnormalities included diffuse or segmental gastric wall thickening (66%, 38/58), lymphadenopathy (40%, 23/58), ulcer (22%, 13/58), and gastric mass (3%, 2/58). Eighteen (31%) of 58 patients were found to have no abnormality. The high-grade group had a higher incidence of abnormalities seen on CT than the low-grade group (100% vs 51%, respectively). Gastric wall thickening in the high-grade group was more diffuse (48% vs 8%) and severe (71% vs 14%; severe or moderate) than that seen in the low-grade group. Lymphadenopathy was visualized in 67% of the high-grade group and in 24% of the low-grade group. Gastric ulcer was found in 57% of the high-grade group and in only 5% of the low-grade group. The gastric mass formation was seen in only two patients in the high-grade group.

CONCLUSION

The CT findings of gastric MALT lymphoma that the two groups had in common were gastric wall thickening and lymphadenopathy. Although our results pointed to no specific CT finding for differentiating high-grade from low-grade gastric MALT lymphomas, we found that the absence of abnormality on CT is highly predictive of low-grade MALT lymphoma.

Molecular phenotype distinguishes two subsets of gastric low-grade mucosa-associated lymphoid tissue lymphomas

Isotype switch recombination together with somatic mutation of immunoglobulin variable genes is indicative of B-cell maturation stage. Because aberrant isotype switch events occur in a proportion of gastric mucosa-associated lymphoid tissue (MALT) lymphomas, we tested whether gastric MALT lymphomas with or without aberrant rearrangements in the switch regions differ in B-cell maturation stage. Southern blot analysis of DNA from six gastric MALT lymphoma cases revealed the presence of aberrant isotype switch events in three cases. Somatic common mutations were present in all immunoglobulin variable heavy chain genes of the six cases, and homology with the closest germline ranged from 89.5% to 98.8%. Replacement versus silent mutation ratio analysis of complementarity-determining regions and frameworks indicated the positive selective pressure of an antigen in four cases. In the remaining two cases, protein translated from the third complementarity-determining region suggested the selective pressure of an autoantigen. The three cases with aberrant isotype switch events showed no uncommon mutations, whereas two of three cases without evidence of aberrant isotype switch showed high levels of such mutations. Moreover the three cases with aberrant isotype switch, compared with the three cases without, showed an increased number of common mutations and of N segment additions. These data raise the possibility of two distinct subsets of gastric low-grade MALT lymphomas, one with aberrant isotype switch and no intraclonal diversification, and one with no aberrant isotype switch but with intraclonal diversification. The first subset may originate from a post-germinal center environment and the second from a germinal center. Alternatively, the first subset may derive from the second after maturation or after a transformation event that blocks the mutational process.

A clinicopathological study of 152 surgically treated primary gastric lymphomas with survival analysis of 109 high grade tumours

AIMS

To describe the clinicopathological features of a large number of surgically treated and followed up primary gastric lymphomas and thereby gain a better understanding of their biology, with particular reference to the prognostic factors of high grade tumours.

METHODS

A retrospective study of 152 patients.

RESULTS

High grade gastric lymphomas, both pure and with a residual low grade component, differed from low grade mucosa associated lymphoid tissue (MALT)-type lymphomas in that they were more frequently large, ulcerated, at an advanced stage, and highly proliferating. In addition, patients were older and had a worse outcome. The prognosis of high grade lymphomas was influenced by patient age, tumour stage, depth of infiltration in the gastric wall, and the invasion of adjacent organs. Adjuvant postsurgical treatment prolonged survival only in patients with advanced stage and deep neoplastic infiltration.

CONCLUSIONS

There is a sharp distinction between low grade MALT-type lymphomas and tumours with a high grade component, justifying their different treatment approach. The postsurgical management of high grade lymphomas should be based on the accurate evaluation of the neoplastic extension.

Treating Helicobacter pylori infection in primary care patients with uninvestigated dyspepsia: the Canadian adult dyspepsia empiric treatment-Helicobacter pylori positive (CADET-Hp) randomised controlled trial

OBJECTIVE

To determine whether a "test for Helicobacter pylori and treat" strategy improves symptoms in patients with uninvestigated dyspepsia in primary care.

DESIGN

Randomised placebo controlled trial.

SETTING

36 family practices in Canada.

PARTICIPANTS

294 patients positive for H pylori ((13)C- urea breath test) with symptoms of dyspepsia of at least moderate severity in the preceding month.

INTERVENTION

PARTICIPANTS were randomised to twice daily treatment for 7 days with omeprazole 20 mg, metronidazole 500 mg, and clarithromycin 250 mg or omeprazole 20 mg, placebo metronidazole, and placebo clarithromycin. Patients were then managed by their family physicians according to their usual care.

MAIN OUTCOME MEASURES

Treatment success defined as no symptoms or minimal symptoms of dyspepsia at the end of one year. Societal healthcare costs collected prospectively for a secondary evaluation of actual mean costs.

RESULTS

In the intention to treat population (n=294), eradication treatment was significantly more effective than placebo in achieving treatment success (50% v 36%; P=0.02; absolute risk reduction=14%; number needed to treat=7, 95% confidence interval 4 to 63). Eradication treatment cured H pylori infection in 80% of evaluable patients. Treatment success at one year was greater in patients negative for H pylori than in those positive for H pylori (54% v 39%; P=0.02). Eradication treatment reduced mean annual cost by $C53 (-86 to 180) per patient.

CONCLUSIONS

A "test for H pylori with (13)C-urea breath test and eradicate" strategy shows significant symptomatic benefit at 12 months in the management of primary care patients with uninvestigated dyspepsia.

Specific entry of Helicobacter pylori into cultured gastric epithelial cells via a zipper-like mechanism

Although Helicobacter pylori has generally been considered an extracellular pathogen, a number of in vitro infection experiments and biopsy examinations have shown that it is capable of occasionally entering mammalian host cells. Here, we characterized this entry process by using AGS cells as a host cell model. In gentamicin protection-invasion assays, the number of H. pylori colonies recovered was lower than that for Salmonella enterica serovar Typhimurium X22, Escherichia coli expressing InvA, and Yersinia enterocolitica YO:9 grown at 25 degrees C but higher than that for Neisseria gonorrhoeae VP1 and Y. enterocolitica YO:9 grown at 37 degrees C. At the ultrastructural level, the entry process was observed to occur via a zipper-like mechanism. Internalized H. pylori was bound in tight LAMP-1-containing vacuoles in close association with condensed filamentous actin and tyrosine phosphorylation signals. Wortmannin, a potent inhibitor of phosphatidylinositol 3-kinase, and calphostin C, an inhibitor of protein kinase C, both inhibited the entry of H. pylori in a sensitive and dose-dependent manner; however, the level of entry was enhanced by sodium vanadate, an inhibitor of tyrosine phosphatases and ATPases. Furthermore, the cytokine tumor necrosis factor alpha antagonized the entry of H. pylori into AGS cells. Collectively, these results demonstrate that the entry of H. pylori into AGS cells occurs via a zipper-like mechanism which involves various host signal transduction events.

Gastric adenocarcinoma in a patient re-infected with H. pylori after regression of MALT lymphoma with successful anti-H. pylori therapy and gastric resection: a case report

BACKGROUND

Helicobacter pylori (H. pylori) has been etiologically linked with primary gastric lymphoma (PGL) and gastric carcinoma (GC). There are a few reports of occurrence of both diseases in the same patients with H. pylori infection.

CASE PRESENTATION

We report a patient with PGL in whom the tumor regressed after surgical resection combined with eradication of H. pylori infection. However, he developed GC on follow up; this was temporally associated with recrudescence/re-infection of H. pylori. This is perhaps first report of such occurrence.

CONCLUSIONS

Possible cause and effect relationship between H. pylori infection and both PGL and GC is discussed. This case also documents a unique problem in management of PGL in tropical countries where re-infection with H. pylori is supposed to be high.

Helicobacter pylori activates the proto-oncogene c-fos through SRE transactivation

Epidemiological studies have demonstrated a strong association between Helicobacter pylori infection and gastric cancer. However, there have been few detailed studies on the mechanism of cellular proliferation by H. pylori. Thus, we examined activation of the proto-oncogene c-fos to elucidate the underlying mechanism of cell proliferation caused by H. pylori. Activation of c-fos was evaluated in human gastric cancer cells (TMK1) by Northern blot and reporter assays with deletion analysis of the c-fos transcriptional control region. c-fos promoter activation and transcription were enhanced when cocultured with cag-positive strains. H. pylori-mediated c-fos promoter activation was inhibited by MEK1/2 inhibitor (U0126). The deletion analysis indicated that serum response element (SRE) was required for the activation of c-fos by H. pylori. In conclusion, c-fos promoter activation and transcription were enhanced through the activation of extracellular signal-regulated kinases (ERK)/mitogen-activated protein kinase (MAPK) cascade in gastric cancer cells when cocultured with H. pylori possessing intact cag PAI. SRE is required for the activation of c-fos by H. pylori. These results suggest a direct involvement of H. pylori infection in cellular proliferation, which may play a role in neoplastic transformation.

Monoclonal gammopathy of undetermined significance predisposing to Helicobacter pylori-related gastric mucosa-associated lymphoid tissue lymphoma

Gastric mucosa-associated lymphoid tissue (MALT)-associated B-cell proliferation may range from benign to malignant, and Helicobacter pylori is the only identified critical antigenic stimulus to the development of gastric MALT. Monoclonal gammopathy of undetermined significance (MGUS) is characterized by B-cell hyper-activation and clonal expansion and is know to predispose to B-cell malignancies. We report a patient with MGUS and H. pylori infection in whom we noted the progression of gastritis to acquired gastric MALT and gastric MALT to MALT lymphoma during a 3-year follow-up.

Conservative treatment of primary gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue: predictive factors of response and outcome

OBJECTIVES

Primary gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue may regress with conservative treatment such as anti-Helicobacterpylori therapy or monochemotherapy. The aims of the present study were to analyze the predictive factors of response to anti-H. pylori treatment, to assess the effects of an adjuvant therapy in responding patients, and to evaluate an alternative therapy in nonresponding patients.

METHODS

From 1995 to 2000, 48 H. pylori-infected patients with localized primary gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue were treated with anti-H. pylori therapy. Endoscopic and endoscopic ultrasonography features and histological grading of large cells' proportion were analyzed. Eradication of H. pylori and tumoral response were assessed at 2 and 6 months, respectively. From 1996, patients in remission at 6 months were randomized to receive either chlorambucil p.o. for 6 months or no treatment. Patients who did not respond to H. pylori eradication received chlorambucil p.o. for 1 yr.

RESULTS

Among the 48 treated patients, 33 (69%) were in complete (n = 28) or in partial (n = 5) remission, and 15 (31%) were in treatment failure at 6 months. H. pylori was eradicated in 47 patients. The response was not correlated with the endoscopic features or with the histological grade. In contrast, it was related to ultrasonographic features: remission was achieved in 76% of patients when no perigastric lymph node was detected versus only 33% when endoscopic ultrasonography showed presence of lymph nodes (p = 0.025). All responding patients remained in remission (median 34 months) whatever the treatment they received (no treatment or chlorambucil). Remission could be achieved with chlorambucil in 58% of the nonresponding patients to anti-H. pylori treatment.

CONCLUSIONS

The major negative predictive factor of the tumoral response to anti-H. pylori treatment in patients with primary gastric low-grade B-cell lymphoma of mucosaassociated lymphoid tissue was the presence of perigastric lymph nodes on endoscopic ultrasonography. In responding patients, remission remained stable, suggesting that adjuvant chemotherapy was not useful. In patients who failed to respond to H. pylori eradication, monochemotherapy with chlorambucil proved to be efficient, but new therapeutic modalities should be evaluated to improve the control of the tumoral process.

Marginal zone cell lymphoma--an update on recent advances

The marginal zone represents one of the distinct compartments of the B-cell area in lymphoid tissues. It is especially well developed in the spleen and in Peyer's patches of the gut, but not in lymph nodes, with the exception of the ones in the mesenterium. However, the pronounced proliferation of so-called 'monocytoid B-cells' that may be seen in some inflammatory conditions of the lymph node may be regarded as a nodal reactive marginal zone cell expansion. The cellular compositions of the marginal zone and the monocytoid B-cell proliferation are similar and both show a heterogeneous population of B-cells, of which the functions are being slowly unravelled. Neoplasms originating in the marginal zone have been recognized in the past and are listed in the REAL classification as marginal zone B-cell lymphomas including extranodal MALT-type lymphomas, splenic marginal zone lymphomas and nodal (monocytoid) marginal zone lymphomas. Marginal zone cell lymphomas display a broad morphological spectrum, which is reflected by the heterogeneity of the cellular composition and the variation in the growth pattern of the lymphoma, but is independent of the anatomical site. All three marginal zone cell lymphomas share immunophenotypic, genetic and chromosomal similarities which will be discussed. The morphologic features are dealt with only briefly as they have been extensively discussed elsewhere.

Gastric MALT lymphoma: from aetiology to treatment

The development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma is dependent on Helicobacter pylori infection. Bacterial colonisation of the gastric mucosa triggers lymphoid infiltration and the formation of acquired MALT. The bacterial infection induces and sustains an actively proliferating B-cell population through direct (autoantigen) and indirect (intratumoral T cells specific for H. pylori) immunological stimulation. Moreover, the bacterial infection provokes a neutrophilic response, which causes the release of oxygen free radicals. These reactive species may promote the acquisition of genetic abnormalities and malignant transformation of reactive B cells. A transformed clone carrying the translocation t(1;18)(q21;q21) forms a MALT lymphoma, the growth of which is independent of H. pylori and will not respond to bacterial eradication. Malignant clones without t(11;18)(q21;q21), but with other genetic abnormalities, such as trisomy 3 or microsatellite instability, depend critically on immune stimulation mediated by H. pylori for their clonal expansion. In the early stages, the tumour can be successfully treated by eradication of the bacterium, whereas at later stages the tumour may escape its growth dependency through acquisition of additional genetic abnormalities such as t(1;14)(p22;q32) and t(1;2)(p22,p12) involving the BCL-10 gene. Finally, further genetic abnormalities, such as inactivation of the tumour suppressor genes, p53 and p16, can lead to high-grade transformation. Detection of these abnormalities may help with the clinical management of patients with gastric MALT lymphoma.

External beam radiation therapy in the treatment of patients with extranodal stage IA non-Hodgkin's lymphoma

The purpose of this report was to study the results of external beam radiotherapy for patients with extranodal stage IA non-Hodgkin's lymphoma (NHL). A retrospective review was carried out on 27 patients seen between 1984 and 1998 with stage IA NHL of extranodal sites, and followed up for a minimum of 1 year. Sites involved included eye/orbit (seven), parotid (five), breast (four), Waldeyer ring (four), thyroid (three), other head and neck (two), stomach (one), and prostate (one). All patients had biopsy-proven disease and underwent staging workup to rule out other sites of disease. Histologic analysis revealed 16 patients with low-grade NHL, 9 with intermediate-grade, and 2 with high-grade. Ten patients received chemotherapy before radiation therapy, and eight of them had a complete response. The remaining 17 patients were treated with external beam radiation therapy alone. Radiation was directed to the involved field at 1.8 Gy to 2.0 Gy per fraction to a median dose of 40 Gy (range: 20-50.4 Gy). The median patient age was 71 years (range: 39-85 years); 55% were female, and 45% were male. A complete response was attained in all 27 patients after radiation therapy. There were five failures (all in uninvolved distant sites), and two deaths during the follow-up. Median disease free survival (DFS) and overall survival (OS) have not been reached. The 5-year DFS and OS are 85% and 94%, respectively. Older age at presentation showed a trend toward worse outcome (p = 0.07), but because of the relatively few events, other factors (radiation dose, grade of disease, sex, or the use of chemotherapy) showed no statistical differences among the patients. External beam radiation therapy is a highly effective treatment for stage IA NHL found in extranodal sites.

Mucosa-associated lymphoid tissue lymphoma

Since the first description of mucosa-associated lymphoid tissue (MALT) lymphoma in 1983 rapid advances have been made in the understanding of the pathogenesis and underlying molecular events associated with the development of this tumor. Lymphoma arises at extranodal sites in which a pre-existing inflammatory response has provoked the acquisition of organized lymphoid tissue. Specific molecular events have been associated with the development of MALT lymphoma including t(11;18) and alterations in Bcl-10 protein expression, and these appear to be interlinked. In gastric MALT lymphoma Helicobacter pylori is the most common stimulus for the acquisition of lymphoid tissue. Eradication of this organism has been shown to result in regression of the tumor in many cases, but there are a few that will not respond to this approach. Predicting those cases unlikely to respond to H pylori eradication alone has been investigated in a number of ways. An underlying t(11;18) within the tumor cells appears to predict for a lack of response. Clinical measurement of the depth of infiltration of the wall by gastric MALT lymphoma as measured by endoscopic ultrasound has been less clear. More superficial tumors are more likely to respond, but regression has been reported even in cases with local lymph node involvement. For superficial lymphomas at other sites alternatives to radiotherapy, chemotherapy, or surgery have been sought. Local injections of interferon (IF) alpha have been successful in treating conjunctival lymphoma, and this approach may be of use for other superficial lesions.

Long-term follow-up of gastric MALT lymphoma after H. pylori eradication

For almost 10 years, we have been familiar with the concept of mucosa-associated lymphoid tissue (MALT)-type lymphoma of the stomach caused by chronic Helicobacter pylori infection. Many epidemiologic, biologic, and molecular genetic studies have implicated H. pylori for its role in lymphoma genesis. Since the first reports on complete remission of gastric MALT lymphomas after cure of bacterial infection, many clinical studies have investigated the effect of eradicating H. pylori on the course of MALT lymphoma, and indeed were able to confirm remission of the lymphoma. To date, more than 650 patients worldwide have been treated for gastric MALT lymphoma with antibiotics, and we have gained many new insights concerning the biologic behavior of this disease, especially from the deepened knowledge of cytogenetics. Furthermore, factors relevant for the prediction of treatment outcome have been identified, which has helped to stratify patients into risk groups.

Helicobacter pylori infection: epidemiology, pathophysiology, and therapy

Helicobacter pylori is one of the most commonly encountered human pathogens. It has been shown to be closely associated with peptic ulcer disease (PUD), gastric adenocarcinoma, and the gastric mucosa-associated lymphoid tissue (MALT) that may lead to gastric lymphoma. The current diagnostic methods include histology, microbiological culture, classic serology, urease activity detection, polymerase chain reaction (PCR) and stool antigen detection. Its treatment modality options are multiple; however, a triple regimen consisting of a proton pump inhibitor (PPI), and two antibiotics for 10 to 14 days is preferred. Drug resistance is a growing problem in this organism and new therapeutic options are currently limited.

Prospective study of Helicobacter pylori eradication therapy in stage I(E) high-grade mucosa-associated lymphoid tissue lymphoma of the stomach

PURPOSE

High-grade mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach are generally believed to be Helicobacter pylori-independent, autonomously growing tumors. However, anecdotal cases of regression of high-grade lymphomas after the cure of H pylori infection had been described. The present prospective study was conducted to evaluate the effect of anti-H pylori therapy in stage I(E) high-grade gastric MALT lymphomas.

PATIENTS AND METHODS

Sixteen patients with H pylori infection and stage I(E) gastric high-grade MALT lymphoma consented to a brief antibiotic therapy as first-line treatment from June 1995 through April 2000. Then, patients underwent intensive endoscopic follow-up examinations (+/- endoscopic ultrasonography) with biopsy to evaluate tumor response. Patients with significant improvement of gross lesions that accompanied regression of large cells were followed up without additional treatment. Patients without significant improvement were immediately referred to systemic chemotherapy.

RESULTS

Eradication of H pylori was achieved in 15 patients and was accompanied by rapid gross tumor regression and disappearance of large cells in 10. All 10 of these patients with early response had subsequent complete histologic remission of lymphoma. The complete remission rate was 62.5% (95% confidence interval, 35.8% to 89.1%). The response rate was not affected by the tumor grading (proportion of large blast cells within the tumor) but was adversely affected by the depth of tumor invasion. At a median follow-up of 43.5 months (range, 21.1 to 67.4 months), all 10 of these patients remained lymphoma-free. The median duration of complete response was 31.2 months (range, 14.4 to 49.1 months).

CONCLUSION

These results suggest that high-grade transformation is not necessarily associated with the loss of H pylori dependence in early-stage MALT lymphomas of the stomach.

Acute Helicobacter pylori infection is followed by an increase in diarrheal disease among Peruvian children

BACKGROUND

Cohort and case-crossover studies were conducted to evaluate whether new Helicobacter pylori infections are followed by increased diarrhea.

METHODS

Participants were 6-month-old to 12-year-old shantytown residents living near Lima, Peru. Baseline data were collected from community households. Health interviews were completed daily, and sera, drawn every 4 months, were tested for H pylori immunoglobulin G. Diarrhea rates among newly H pylori-infected (seroconverting) children were compared with rates among persistently uninfected and infected children using cohort and case-crossover analyses.

RESULTS

Sera were obtained from 345 children from January 1, 1995, through September 1, 1997. H pylori incidence was 12% per year (36 H pylori infections in 109 866 seronegative days). In adjusted cohort analyses, seroconverters had more diarrhea days (rate ratio: 2.0; 95% confidence interval: 1.6-2.4), episodes, and sick days in the year after infection than did uninfected children; and more diarrhea days and sick days than did persistently infected children. This effect was strongest in the first 2 months. Case-crossover analyses supported these findings.

CONCLUSION

Preventing H pylori infection may help reduce pediatric diarrheal disease.

Resolution of granulomatous rosacea after eradication of Helicobacter pylori with clarithromycin, metronidazole and pantoprazole

The aetiopathogenetic role of Helicobacter pylori in rosacea remains controversial. We report a 27-year-old man with a 4-year history of intractable rosacea. Histopathology showed epithelioid granulomas. H. pylori infection was proven directly on gastroscopy and by serological testing. Treatment with clarithromycin, metronidazole and pantoprazole eradicated H. pylori. Skin changes were markedly improved by the end of this therapy and had resolved completely 2 months later. The patient has been followed up, and has remained free of symptoms for 3 years. We suggest that H. pylori may be involved in the aetiopathogenesis of granulomatous rosacea.