Helicobacter pylori eradication for low-grade gastric mucosa-associated lymphoid tissue lymphoma is more successful in inducing remission in distal compared to proximal disease

Effectiveness of Helicobacter pylori eradication in the treatment of early-stage gastric mucosa-associated lymphoid tissue lymphoma: An up-to-date meta-analysis

BACKGROUND

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma (GML) is usually a low-grade B-cell neoplasia strongly associated with Helicobacter pylori (H. pylori)-induced chronic gastritis. Clinical practice guidelines currently recommend H. pylori eradication as the preferred initial treatment for early-stage GML. To determine the practical effect of bacterial eradication as the sole initial therapy for early-stage GML, an updated analysis and review of available evidence is imperative.

AIM

To perform a meta-analysis to assess the rate of complete remission (CR) of H. pylori-positive early-stage GML following bacterial eradication.

METHODS

We performed independent, computer-assisted literature searches using the PubMed/MEDLINE, Embase, and Cochrane Central databases through September 2022. Prospective and retrospective observational studies evaluating the CR of early-stage GML following bacterial eradication in H. pylori-positive patients. The risk of bias was assessed using Joanna Briggs Institute (JBI) Critical Appraisal Tools. The pooled estimate of the complete histopathological remission rate and respective confidence intervals (95%CI) were calculated following the random-effects model. Heterogeneity and inconsistency were assessed using Cochran’s Q test and I² statistic, and heterogeneity was defined as P < 0.01 and I² > 50%, respectively. Subgroup and meta-regression analyses were conducted to explore potential sources of heterogeneity.

RESULTS

The titles and abstracts of 1576 studies were screened; 96 articles were retrieved and selected for full-text reading. Finally, 61 studies were included in the proportional meta-analysis (P-MA). Forty-six were prospective and fifteen were retrospective uncontrolled, single-arm, observational studies. The overall risk of bias was low to moderate in all but a single report, with an average critical appraisal score across all studies of 79.02%. A total of 2936 H. pylori-positive early-stage GML patients, in whom H. pylori was successfully eradicated, were included in the analysis. The pooled CR of H. pylori-positive early-stage GML after bacterial eradication was 75.18% (95%CI: 70.45%-79.91%). P-MA indicated the substantial heterogeneity in CR reported across studies (I² = 92%; P < 0.01). Meta-regression analysis identified statistically significant effect modifiers, including the proportion of patients with t(11;18)(q21;q21)-positive GML and the risk of bias in each study.

CONCLUSION

Comprehensive synthesis of available evidence suggests that H. pylori eradication is effective as the sole initial therapy for early-stage GML. Although the substantial heterogeneity observed across studies limits the interpretation of the pooled overall CR, the present study is a relevant to informing clinical practice.

Effect of Helicobacter pylori eradication therapy on the response of MALT-Gastric lymphoma

INTRODUCTION

The link between gastric mucosa-associated lymphoid tissue lymphoma (LG-MALT) and chronic Helicobacter Pylori (HP) infection had led to a real revolution in the management of the disease.

AIMS

To study the results of the HP eradication therapy and to clarify its place in the tumor response.

METHODS

A descriptive retrospective bicentric study, between January 2007 and December 2016, including patients with LG-MALT treated in the gastroenterology departments of Sahloul hospital in Sousse and Habib Bougtafa hospital in Bizerte, and having received treatment for eradication of HP.

RESULTS

Sixty-three patients were included. The male/female sex ratio was 1.42. The average age was 58 years. The symptomatology was dominated by epigastric pain (96.8%). On digestive endoscopy, the most frequent location and appearance were gastric antrum (39.6%) and ulcerations (89%). The lymphoma was classified as stage IE and IIE1 in 81% and 19% of cases, respectively. The HP status was positive in all patients. The HP eradication rate was 82.5% after three anti-HP treatment courses. Complete remission of lymphoma was obtained in 81% of patients at 18 months. Non-response to HP eradication therapy was observed in 19% of patients. Non-responder patients had a longer diagnostic delay (p=0.02), more diffuse endoscopic involvement (p=0.001) and a more frequent appearance of large gastric folds (p=0.001).

CONCLUSION

The course of LG-MALT is determined by the treatment for the eradication of HP. Its success promotes remission of lymphoma.

Treatment of indolent lymphoma

Treatment of indolent lymphoma has improved significantly in recent decades since the advent of rituximab (anti-CD20 monoclonal antibody). Although, some patients with limited disease can be cured with radiation therapy alone, most patients experience disease progression and recurrence during follow-up despite early initiation of treatment. Thus, watch-and-wait is still regarded the standard for asymptomatic patients. Patients with indolent lymphoma have a significant heterogeneity in terms of tumor burden, symptoms (according to anatomical sites) and the need for instant therapy. Therefore, the initiation of treatment and treatment option should be decided with a clear goal in each patient according to the need for therapy and clinical benefits with the chosen treatment. In this review, we cover the current treatment of follicular lymphoma and marginal zone lymphoma.

Long-Term Clinical Outcome and Predictive Factors for Relapse after Radiation Therapy in 145 Patients with Stage I Gastric B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue Type

Simple Summary

Helicobacter pylori-associated gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) constitutes >80% of gastric MALT lymphoma. Eradication therapy has been accepted as a standard approach for initial treatment. However, in patients who present without evidence of infection or who fail to respond to eradication therapy, a solid consensus for treatment is not available. Furthermore, few studies have evaluated the predictive factors for response or relapse after radiation therapy (RT) as heterogeneous, relatively small study populations have been treated with RT, and only a small number of events have been reported after treatment. In this study, we report the long-term clinical outcome of stage I gastric MALT lymphoma treated with RT. We also identified that the tumor’s dominant location in the stomach is a predictive factor for relapse after RT.

Abstract

This study aimed to evaluate the clinical outcomes of radiation therapy (RT) for stage I gastric mucosa-associated lymphoid tissue (MALT) lymphoma and find predictive factors for relapse after RT. This retrospective study included 145 patients without a prior history of treatment, except Helicobacter pylori eradication therapy, who were irradiated for stage I gastric MALT lymphoma. The gastric body was the most commonly involved location of the dominant lesion (66.9%), and H. pylori infection at first diagnosis was detected in 61 (42.1%) patients. The median RT dose was 30 Gy (range, 24–40). Seven patients had an autoimmune disease. All patients except one achieved a complete remission at post-treatment endoscopic biopsy after a median of 2 months (range, 1–36). During the median follow-up at 51 months (range, 2–146), 11 patients experienced relapses: in the stomach (n = 5), in a distant site (n = 4), and in both (n = 2). The five-year overall, local relapse-free, distant relapse-free, and relapse-free survival (RFS) rates were 98.6%, 94.0%, 97.1%, and 92.3%, respectively. In multivariate analysis for RFS, the location of MALT lymphoma other than in the gastric body was significantly associated with an increased risk of relapse (hazard ratio 5.85 (95% CI 1.49–22.9), p = 0.011). RT results in favorable clinical outcomes in patients with stage I gastric MALT lymphoma. Tumor location could be a predictive factor for relapse after RT.

Mucosa-associated lymphoid tissue lymphoma with isolated endobronchial involvement

Primary pulmonary lymphoma is an uncommon disease, and extranodal marginal zone lymphoma of mucosa‐associated lymphoid tissue (MALT) is the most common type of pulmonary lymphoma. The most frequent pattern observed in chest computed tomography (CT) is consolidation, followed by nodules and mass. The differentiation of pulmonary MALT lymphoma from other lung diseases is critical for disease management and treatment. However, pulmonary MALT lymphoma with isolated endobronchial manifestation has seldomly been reported. Here, we report a case of an elderly woman who presented with a four‐month history of cough, dyspnoea, and haemoptysis. Chest CT scan revealed left main bronchus narrowing without lung parenchymal lesion. Bronchoscopic examination was performed, and the diagnosis of primary pulmonary MALT lymphoma with isolated endobronchial involvement was made. She has been successfully treated with rituximab.

[Diagnosis and Treatment of Gastric Mucosa-associated Lymphoid Tissue Lymphoma]

The stomach is the most common primary site of an extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type, which is characterized by an indolent clinical course. A diagnosis of gastric MALT lymphoma requires an endoscopic biopsy that should be confirmed by an experienced pathologist. Gastric MALT lymphoma shows a variable endoscopic appearance, including erosion, erythema, discoloration, atrophy, ulcer, and subepithelial lesion. The distribution is often multifocal. Therefore, clinical suspicion and multiple biopsies are essential for an accurate diagnosis. Gastric MALT lymphoma is almost invariably associated with a Helicobacter pylori (H. pylori) infection. H. pylori eradication therapy is the mainstay of treatment, which must be delivered to all patients regardless of the H. pylori infection status or stage. For patients who have failed to achieve remission following eradication therapy, radiotherapy or chemotherapy can be considered. Radiotherapy is an effective treatment modality for a localized stage and shows excellent outcomes. In the presence of disseminated or advanced disease, chemotherapy and/or immunotherapy with the anti-CD20 monoclonal antibody, rituximab, can be applied. Treatment should be individualized according to the stage and symptoms, as well as the patients' preference. Given that the clinical course of gastric MALT lymphoma is usually indolent, watchful waiting may be an adequate strategy in selected cases where scheduled follow-up is guaranteed.

Novel Insights of Lymphomagenesis of Helicobacter pylori-Dependent Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the most common subtype of gastric lymphoma. Most gastric MALT lymphomas are characterized by their association with the Helicobacter pylori (HP) infection and are cured by first-line HP eradication therapy (HPE). Several studies have been conducted to investigate why most gastric MALT lymphomas remain localized, are dependent on HP infection, and show HP-specific intratumoral T-cells (e.g., CD40-mediated signaling, T-helper-2 (Th2)-type cytokines, chemokines, costimulatory molecules, and FOXP3+ regulatory T-cells) and their communication with B-cells. Furthermore, the reason why the antigen stimuli of these intratumoral T-cells with tonic B-cell receptor signaling promote lymphomagenesis of gastric MALT lymphoma has also been investigated. In addition to the aforementioned mechanisms, it has been demonstrated that the translocated HP cytotoxin-associated gene A (CagA) can promote B-cell proliferation through the activation of Src homology-2 domain-containing phosphatase (SHP-2) phosphorylation-dependent signaling, extracellular-signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), B-cell lymphoma (Bcl)-2, and Bcl-xL. Furthermore, the expression of CagA and these CagA-signaling molecules is closely associated with the HP-dependence of gastric MALT lymphomas (completely respond to first-line HPE). In this article, we summarize evidence of the classical theory of HP-reactive T-cells and the new paradigm of direct interaction between HP and B-cells that contributes to the HP-dependent lymphomagenesis of gastric MALT lymphomas. Although the role of first-line HPE in the treatment of HP-negative gastric MALT lymphoma remains uncertain, several case series suggest that a proportion of HP-negative gastric MALT lymphomas remains antibiotic-responsive and is cured by HPE. Considering the complicated interaction between microbiomes and the genome/epigenome, further studies on the precise mechanisms of HP- and other bacteria-directed lymphomagenesis in antibiotic-responsive gastric MALT lymphomas are warranted.

The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic

Innate immunity represents the first barrier against bacterial invasion. Toll-like receptors (TLRs) belong to the large family of pattern recognition receptors (PRRs), and their activation leads to the induction of inflammatory cytokines, chemokines, antigen-presenting molecules, and costimulatory molecules. Recent studies have focused on identifying the association between TLRs and Helicobacter pylori- (H. pylori-) related diseases. Therefore, this minireview focuses on assessing the role of these TLRs in the development of H. pylori-related gastropathies. Both TLR2 and TLR were found to be involved in H. pylori LPS recognition, with contradictory results most likely due to both the inability to obtain pure LPS in experimental studies and the heterogeneity of the bacterial LPS. In addition, TLR2 was found to be the most extensively expressed gene among all the TLRs in gastric tumors. High levels of TLR4 were also associated with a higher risk of gastric cancer. TLR5 was initially associated with the recognition of H. pylori flagellin, but it seems that this bacterium has developed mechanisms to escape this recognition representing an important factor involved in the persistence of this infection and subsequent carcinogenesis. TLR9, the only TLR with both anti- and proinflammatory roles, was involved in the recognition of H. pylori DNA. The dichotomous role of TLR9, promoting or suppressing the infection, depends on the gastric environment. Recently, TLR7 and TLR8 were shown to recognize purified H. pylori RNA, thereby inducing proinflammatory cytokines. TLR1 and TLR10 gene polymorphisms were associated with a higher risk for gastric cancer in H. pylori-infected individuals. Different gene polymorphisms of these TLRs were found to be associated with gastric cancer depending mostly on ethnicity. Further studies are required in order to develop preventive and therapeutic strategies against H. pylori infections based on the functions of TLRs.

[Clinical Efficacy of Radiotherapy in Helicobacter pylori Negative or Unresponsive to Eradication Therapy Primary Gastric Mucosa-Associated Lymphoid Tissue Lymphoma]

Background/Aims

The eradication of Helicobacter pylori (H. pylori) is an effective treatment in gastric mucosa-associated lymphoid tissue (MALT) lymphoma associated with H. pylori infection. However, the treatment strategy in gastric MALT lymphoma patients who are H. pylori-negative or unresponsive to H. pylori eradication therapy remains controversial. In this study, we investigated the clinical efficacy of treatments other than H. pylori eradication therapy in these groups of patients.

Methods

This was a retrospective single-center study based on the medical records of patients diagnosed with gastric MALT lymphoma at Yeungnam University Medical Center between January 2005 and December 2016. Patients were treated with H. pylori eradication therapy, chemotherapy, or radiotherapy according to their H. pylori infection status and stage of gastric MALT lymphoma.

Results

Of the 68 eligible patients, 50 were enrolled in the study. Of the 42 patients with H. pylori-positive gastric MALT lymphoma, 36 (81.7%) were treated with H. pylori eradication therapy as primary treatment and 25 (69.4%) achieved a complete response (CR). Patients without a CR after H. pylori eradication therapy (n=11, 30.6%) received radiotherapy as a secondary treatment. Two patients with H. pylori-positive gastric MALT lymphoma and eight with H. pylori-negative gastric MALT lymphoma received radiotherapy as the primary treatment. CR was achieved in all 21 patients treated with radiotherapy as primary or secondary treatment. The 5-year progression-free survival rate after radiotherapy was 92.9%.

Conclusions

Radiotherapy may be a worthwhile treatment option in patients with H. pylori-negative MALT lymphoma or H. pylori-positive MALT lymphoma that is not responsive to H. pylori eradication therapy.

Anti-Helicobacter pylori therapy in localized gastric mucosa-associated lymphoid tissue lymphoma: A prospective, nationwide, multicenter study in Japan

BACKGROUND

Helicobacter pylori eradication therapy was approved in Japan for the first-line, standard treatment of H. pylori-positive gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Although several retrospective studies or small-scale single-center studies have been reported, a prospective, large-scale, nationwide, multicenter study has not been reported from Japan.

MATERIALS AND METHODS

We conducted a prospective, nationwide, multicenter study to evaluate the clinical efficacy of rabeprazole-based triple H. pylori eradication therapy for patients with localized gastric MALT lymphoma in practice-based clinical trial. A total of 108 H. pylori-positive patients with stage I/II₁ gastric MALT lymphoma underwent H. pylori eradication therapy. The primary endpoints were complete remission (CR) rate and the rate of transfer to secondary treatment. The secondary endpoints were CR maintenance duration and overall survival (OS).

RESULTS

CR of lymphoma was achieved in 84 of 97 patients (86.6%), during the period 2.0-44.7 months (median, 5.3 months) after starting H. pylori eradication treatment. CR was maintained in 77 of 81 patients (95.1%) for 0.4-53.2 months (median, 33.1 months). Secondary treatments (radiotherapy, rituximab, or gastrectomy) for gastric MALT lymphoma were needed in 10 of the 97 patients (10.31%). During follow-up, OS rate was 96.9% (94/97) and the causes of 3 deaths were not related to lymphoma.

CONCLUSIONS

Rabeprazole-based H. pylori eradication therapy demonstrated a high CR rate, long CR maintenance, and a good OS for patients with localized gastric MALT lymphoma in this prospective, practice-based, multicenter study.

Radiotherapy for localized gastric mucosa-associated lymphoid tissue lymphoma: long-term outcomes over 10 years

This study aimed to assess the long-term outcomes of radiotherapy in patients with localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Twenty-seven patients with Stage I gastric MALT lymphoma were treated with radiotherapy from 1999 to 2010. The median age was 65 years (range: 31-84). Fifteen patients were Helicobacter pylori-negative. Thirteen patients were treated with definitive radiotherapy alone. The other 14 patients who had refractory or residual disease following a prior treatment received salvage radiotherapy. The median dose of the radiotherapy was 30 Gy in 20 fractions (range: 30-39.5 Gy). The median follow-up period was 121 months (range: 8-176 months). The 5- and 10-year overall survival rates for all patients were 92% and 87%, respectively. No patients died from MALT lymphoma. Three patients died of other diseases at 8, 33 and 74 months after radiotherapy (myocardial infarction, pneumonia and hepatocellular carcinoma, respectively). No cases of local recurrence were observed during the follow-up period. There were no serious late gastric, liver or kidney complications during a median follow-up period of over 10 years. Two patients remain alive with distant metastases: a lung metastasis and an abdominal lymph node metastasis at 104 months and 21 months after radiotherapy, respectively. Excellent long-term local control was observed in patients with localized gastric MALT lymphoma after radiotherapy. However, lifelong follow-up should be conducted to detect cases of late recurrence, especially distant metastases.

[Gastric Mucosa-associated Lymphoid Tissue Lymphoma Based on Outcome of Domestic Treatment]

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is associated with Helicobacter pylori infection. H. pylori eradication can be performed as a primary therapy regardless of H. pylori status. In Korea, six articles were published about low-grade gastric MALT lymphoma with H. pylori. Complete regression rate after H. pylori eradication is reported at 74.5% to 94.4%. Radiotherapy results in favorable clinical long-term outcomes in patients with early-stage gastric MALT lymphoma who fail H. pylori eradication therapy and those who are H. pylori negative. Chemotherapy could be reserved for patients with metastatic or high-grade lymphoma. In gastric MALT lymphoma, patients with polypoid type on initial endoscopy had a higher likelihood of recurrence than those with diffuse infiltration or ulceration types. The depth of invasion, location of lesions, and chromosomal abnormality with t(11;18) together are predictive factors for failure to remission by H. pylori eradication.

Clinical characteristics of primary gastric lymphoma detected during screening for gastric cancer in Korea

BACKGROUND AND AIM

The role of screening endoscopy in primary gastric lymphoma (PGL) has not been investigated. This study aimed to evaluate the clinical characteristics and outcomes of PGLs detected by screening endoscopy in the high prevalence area of Helicobacter pylori (H. pylori) infection.

METHODS

This retrospective cohort study enrolled consecutive subjects who were diagnosed with PGL by endoscopic screening in Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Korea, between October 2003 and September 2013. The characteristics and outcome of screening-detected patients (screening group) were compared with consecutive subjects diagnosed with PGL in the outpatient clinic (outpatient group).

RESULTS

Of the 105 194 recipients of screening upper endoscopy, 52 (0.049%) were found to have PGL. The median age was 54.2 years (range 23-79), and 65.4% were women. The proportion of PGL to gastric malignancy was 12.1% (52/429) overall, but >30% (25/73) in middle-aged (40-59) women. PGLs in the screening group were more likely to be mucosa-associated lymphoid tissue lymphoma (98.1% vs 60.0%, P < 0.001) and treated with H. pylori eradication alone (90.0% vs 48.1%, P < 0.001) than those in the outpatient group. Moreover, the screening group showed better 5-year overall survival (100.0% vs 89.3%, P = 0.016) and progression-free survival (94.9% vs 83.4%, P = 0.040) than the outpatient group.

CONCLUSIONS

In Korea, a high prevalence area of H. pylori infection, PGL seems more prevalent than in Western countries. Endoscopic screening may help to detect early stage H. pylori-positive mucosa-associated lymphoid tissue lymphoma. A high index of suspicion is needed, especially in middle-aged women.

Clinical Outcome of Eradication Therapy for Gastric Mucosa-Associated Lymphoid Tissue Lymphoma according to H. pylori Infection Status

Background. To evaluate the long-term outcome of H. pylori eradication therapy for gastric MALT lymphoma according to the presence of H. pylori infection. Methods. We retrospectively reviewed the medical records of patients between January 2001 and June 2014. The clinicopathologic characteristics and clinical outcomes were compared between H. pylori-positive and H. pylori-negative gastric MALT lymphoma groups. Results. Fifty-four patients were enrolled: 12 H. pylori-negative and 42 H. pylori-positive patients. The tumor was located more frequently in both the proximal and distal parts of the stomach (P = 0.001), and the percentage of multiple lesions was significantly greater in the H. pylori-negative group (P = 0.046). Forty-seven patients received initial eradication therapy, and 85% (35/41) of H. pylori-positive patients and 50% (3/6) of H. pylori-negative patients achieved complete remission after eradication therapy. The presence of multiple lesions was a predictive factor for unresponsiveness to H. pylori eradication (P = 0.024). The efficacy of eradication therapy (P = 0.133), complete remission (CR) maintenance period, and relapse after eradication therapy were not significantly different between the two groups. Conclusions. H. pylori eradication therapy could be an effective first-line treatment for localized H. pylori-negative gastric MALT lymphoma, especially for single lesions.

Infectious Aetiology of Marginal Zone Lymphoma and Role of Anti-Infective Therapy

Marginal zone lymphomas have been associated with several infectious agents covering both viral and bacterial pathogens and in some cases a clear aetiological role has been established. Pathogenetic mechanisms are currently not completely understood. However, the role of chronic stimulation of the host immune response with persistent lymphocyte activation represents the most convincing explanation for lymphoproliferation. Gastric MALT lymphoma is strictly associated with Helicobacter pylori infection and various eradicating protocols, developed due to increasing antibiotic resistance, represent the first line therapy for gastric MALT. The response rate to eradication is good with 80% of response at 1 year; this finding is also noteworthy because it recapitulates cancer cured only by the antibacterial approach and it satisfies the Koch postulates of causation, establishing a causative relationship between Hp and gastric MALT lymphoma. Patients with chronic HCV infection have 5 times higher risk to develop MZL, in particular, an association with splenic and nodal MZL has been shown in several studies. Moreover, there is evidence of lymphoma regression after antiviral therapy with interferon+ribavirin, thus raising hope that newly available drugs, extremely efficient against HCV replication, could improve outcome also in HCV-driven lymphomas. Another case-study are represented by those rare cases of MZL localized to orbital fat and eye conjunctivas that have been associated with Chlamydophila psittaci infection carried by birds. Efficacy of antibacterial therapy against C. psittaci are conflicting and generally poorer than gastric MALT. Finally, some case reports will cover the relationship between primary cutaneous B-cell Lymphomas and Borrelia Burgdorferi.

Antisecretory medication is associated with decreased Helicobacter pylori detection in gastric marginal zone lymphoma

Helicobacter pylori status influences the prognosis and management of gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), so accurate determination of H pylori status is of clinical importance. The low rate of histologic H pylori positivity among gastric MALT lymphoma cases at our institution prompted investigation for possible causes. A case series of 24 patients as having gastric MALT lymphoma (with no diffuse large B-cell component) in a tertiary care setting between 1997 and 2010 was identified, and clinical records were reviewed. Immunohistochemical staining for H pylori and BCL10 was performed. This study received institutional review board approval (protocol number M13-033). Thirty-nine percent of cases (9/23) were H pylori positive by histology, and 4 additional patients had positive serologic results; overall, 57% of cases (13/23) were positive for H pylori. Treatment with antisecretory medications was associated with a lower likelihood of histologic positivity (13% among treated patients vs 75% among untreated; P = .04). Nuclear localization of BCL10 was seen in 2 cases and was not associated with H pylori status. Antisecretory medications decrease the likelihood of histologic detection of H pylori in gastric MALT lymphoma cases. Incorporation of results of serologic or other testing is needed to ensure correct classification with respect to H pylori status.

Management of the marginal zone lymphomas

Marginal zone lymphomas (MZL) represent around 8 % of all non-Hodgkin lymphomas. During the last decades a number of studies have addressed the mechanisms underlying the disease development. Extranodal MZL lymphoma usually arises in mucosal sites where lymphocytes are not normally present from a background of either autoimmune processes, such as Hashimoto thyroiditis or Sjögren syndrome or chronic infectious conditions. In the context of a persistent antigenic stimulation, successive genetic abnormalities can progressively hit a B-cell clone among the reactive B-cells of the chronic inflammatory tissue and give rise to a MALT lymphoma. The best evidence of an etiopathogenetic link is available for the association between Helicobacter pylori-positive gastritis and gastric MALT lymphoma. Indeed, a successful eradication of this micro-organism with antibiotics can be followed by gastric MALT lymphoma regression in more than 2/3 of cases. Other microbial agents have been implicated in the pathogenesis of MZL arising in the skin (Borrelia burgdorferi), in the ocular adnexa (Chlamydophila psittaci), and in the small intestine (Campylobacter jejuni). The prevalence of hepatitis C virus (HCV) has also been reported higher in MZL patients (particularly of the splenic type) than in the control population, suggesting a possible causative role of the virus. In non-gastric MALT lymphoma and in splenic MZL the role of the antimicrobial therapy is, however, less clear. This review summarizes the recent advances in Marginal Zone Lymphomas, addressing the critical points in their diagnosis, staging and clinical management.

Endoscopic features of gastro-intestinal lymphomas: From diagnosis to follow-up

Many progresses have been done in the management of gastrointestinal (GI) lymphomas during last decades, especially after the discovery of Helicobacter pylori-dependent lymphoma development. The stepwise implementation of new endoscopic techniques, by means of echoendoscopy or double-balloon enteroscopy, enabled us to more precisely describe the endoscopic features of GI lymphomas with substantial contribution in patient management and in tailoring the treatment strategy with organ preserving approaches. In this review, we describe the recent progresses in GI lymphoma management from disease diagnosis to follow-up with a specific focus on the endoscopic presentation according to the involved site and the lymphoma subtype. Additionally, new or emerging endoscopic technologies that have an impact on the management of gastrointestinal lymphomas are reported. We here discuss the two most common subtypes of GI lymphomas: the mucosa-associated lymphoid tissue and the diffuse large B cell lymphoma. A general outline on the state-of-the-art of the disease and on the role of endoscopy in both diagnosis and follow-up will be performed.

Treatment outcome for gastric mucosa-associated lymphoid tissue lymphoma according to Helicobacter pylori infection status: a single-center experience

Background/Aims

Helicobacter pylori eradication therapy has been used as a first-line treatment for H. pylori-positive gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, the management strategy for H. pylori-negative MALT lymphoma remains controversial. Therefore, the aim of this study was to examine the success rate of each treatment option for H. pylori-positive and H. pylori-negative gastric MALT lymphomas.

Methods

In total, 57 patients with gastric MALT lymphoma diagnosed between December 2000 and June 2012 were enrolled in the study. The treatment responses were compared between H. pylori-positive and H. pylori-negative gastric MALT lymphomas.

Results

Of the 57 patients, 43 (75%) had H. pylori infection. Forty-eight patients received H. pylori eradication as a first-line treatment, and complete remission was achieved in 31 of the 39 patients (80%) with H. pylori-positive MALT lymphoma and in five (56%) of the nine patients with H. pylori-negative MALT lymphoma; no significant difference was observed between the groups (p=0.135). The other treatment modalities, including radiation therapy, chemotherapy, and surgery, were effective irrespective of H. pylori infection status, with no significant difference in the treatment response between H. pylori-positive and H. pylori-negative MALT lymphomas.

Conclusions

H. pylori eradication therapy may be considered as a first-line treatment regardless of H. pylori infection status.

Role of Helicobacter pylori virulence factor cytotoxin-associated gene A in gastric mucosa-associated lymphoid tissue lymphoma

Helicobacter pylori (H. pylori) infection might initiate and contribute to the progression of lymphoma from gastric mucosa-associated lymphoid tissue (MALT). Increasing evidence shows that eradication of H. pylori with antibiotic therapy can lead to regression of gastric MALT lymphoma and can result in a 10-year sustained remission. The eradication of H. pylori is the standard care for patients with gastric MALT lymphoma. Cytotoxin-associated gene A (CagA) protein, one of the most extensively studied H. pylori virulence factors, is strongly associated with the gastric MALT lymphoma. CagA possesses polymorphisms according to its C-terminal structure and displays different functions among areas and races. After being translocated into B lymphocytes via type IV secretion system, CagA deregulates intracellular signaling pathways in both tyrosine phosphorylation-dependent and -independent manners and/or some other pathways, and thereby promotes lymphomagenesis. A variety of proteins including p53 and protein tyrosine phosphatases-2 are involved in the malignant transformation induced by CagA. Mucosal inflammation is the foundational mechanism underlying the occurrence and development of gastric MALT lymphoma.

A retrospective study of 5-year outcomes of radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication therapy

BACKGROUND

The favorable response rate of radiotherapy for localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication has been demonstrated. However, there are limited data available on the long-term outcomes. The aim of this retrospective study was to evaluate the long-term outcomes of radiotherapy for localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication.

METHODS

Thirty-four consecutive patients with localized gastric mucosa-associated lymphoid tissue lymphoma that were refractory to eradication were treated with radiotherapy (a total dose of 30 Gy). The response and adverse events of radiotherapy were retrospectively analyzed as short-term outcomes, and recurrence-free, overall and disease-specific survival rates were calculated as long-term outcomes.

RESULTS

Thirty-three (97.1%) patients achieved complete remission and radiotherapy was well tolerated. One patient underwent emergency gastrectomy due to severe hematemesis. Of the 34 patients during the median follow-up period of 7.5 (1.2-13.0) years, one patient had local recurrence after 8.8 years, one patient underwent surgery for bowel obstruction secondary to small bowel metastasis after 5.1 years and one patient had pulmonary metastasis after 10.9 years. Pathologically, all three recurrences revealed mucosa-associated lymphoid tissue lymphoma without any transformation to high-grade lymphoma. None died of gastric mucosa-associated lymphoid tissue lymphoma. The 5-year recurrence-free survival rate was 97.0%. The 5-year overall survival rates and disease-specific survival rates were 97.0 and 100%, respectively.

CONCLUSIONS

Radiotherapy in patients with localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication can achieve excellent overall survival. However, long-term surveillance is necessary to identify late recurrences.

Eradication therapy is effective for Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphomas are extra-nodal B-cell lymphomas arising from MALT, and the most commonly affected organ is the stomach. Helicobacter pylori (H. pylori) eradication therapy with proton-pump inhibitors and antibiotics is the first-line therapy for H. pylori-positive gastric MALT lymphomas, but the effectiveness of the therapy for H. pylori-negative gastric MALT lymphomas remains controversial. Hence, we aimed to evaluate the effectiveness of this eradication therapy for H. pylori-negative MALT lymphomas. The H. pylori infection status of 158 gastric MALT lymphoma patients followed in our unit was judged by urea breath test, rapid urease test, histology of the biopsy specimen taken from the stomach during endoscopy, and serum antibody against H. pylori. Seventeen patients that were negative for all four tests and did not have gastric mucosal atrophy were treated with antibiotic eradication therapy. The average age at diagnosis was 56.8 years old (range: 36-73 years), and the median follow-up period after H. pylori eradication in all 17 patients was 5.3 years (range: 0.3-12.7 years). Five patients (29.4%) achieved complete remission (CR) by eradication therapy alone. Comparison between the responding and non-responding patients revealed that the patients endoscopically diagnosed to have a single lesion of gastric MALT lymphoma were seen only in the responding group, whereas all non-responding patients had multiple lesions (P < 0.05). In conclusion, H. pylori eradication therapy achieved a favorable CR rate in H. pylori-negative gastric MALT lymphoma patients and could be considered as a first-line therapy, especially for patients with a single lesion.

Helicobacter pylori in gastric malignancies

Helicobacter pylori infection remains common worldwide and is significantly associated with gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT)lymphoma. This article reviews recent developments in the field of H. pylori with an emphasis on mechanisms of carcinogenesis, and the bacterial, environmental and host factors that may alter risk of developing gastric cancer or gastric MALT lymphoma. The topic of eradication of H. pylori to prevent the development of malignancy and the possibility of a vaccine against H. pylori are also explored.

Review article: common misconceptions in the management of Helicobacter pylori-associated gastric MALT-lymphoma

BACKGROUND

Helicobacter pylori infection is the main cause of gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

AIM

To review several common misconceptions in the management of H. pylori-associated gastric MALT-lymphoma.

METHODS

Bibliographical searches were performed in MEDLINE up to June 2011.

RESULTS

If adequate diagnostic methods are used, and if only low-grade lymphomas are considered, the prevalence of H. pylori infection is very high (almost 90%). H. pylori eradication is effective in treating approximately 80% of patients with early stage lymphoma. In H. pylori-positive gastric high-grade lymphomas, antibiotic therapy should always be prescribed, as approximately 50% of them regress after H. pylori eradication. Patients with early stage MALT lymphoma negative for H. pylori might still benefit from antibiotic treatment as the sole treatment. Complete remission of gastric MALT lymphoma after H. pylori eradication can take even >12 months. PCR assay for the detection of monoclonal B cells remains positive in many cases after complete remission has been reached. Patients with a persistent clonal band should not be treated unless the lymphoma can be histologically demonstrated. Synchronous occurrence of gastric adenocarcinoma and MALT lymphoma has been repeatedly reported. In some patients in complete remission, eradication of H. pylori does not prevent later development of early gastric cancer. Gastric lymphoma recurrence occurs in some patients after both bacterial and lymphoma regression. H. pylori reinfection does not constitute a prerequisite for lymphoma recurrence.

CONCLUSIONS

The present article states several misconceptions in the management of H. pylori-associated gastric MALT-lymphoma in clinical practice, reviews the related scientific evidence and proposes the adequate attitude in each case.

[Helicobacter pylori eradication for stage I(E₁) gastric mucosa-associated lymphoid tissue lymphoma: predictive factors of complete remission]

BACKGROUND/AIMS

Eradication of Helicobacter pylori (H. pylori) is accepted as initial treatment of stage I(E₁) gastric mucosa associated lymphoid tissue (MALT) lymphoma. However, 10-20% of gastric low grade MALT lymphomas are unresponsive to H. pylori eradication treatment. The aim of this study was to find out the predictive factors of complete remission of gastric MALT lymphoma after H. pylori eradication.

METHODS

From 1995 to 2006, consecutive 95 patients with modified Ann Arbor stage I(E₁) gastric MALT lymphoma were enrolled, and their medical records were reviewed. The patients were initially treated by H. pylori eradication. The complete remission was determined by endoscopic and histologic finding.

RESULTS

Eighty eight patients (92.6%) achieved complete remission after H. pylori eradication therapy. Mean follow up time for these patients was 40+/-25 months. Seven patients (7.4%) failed to achieve complete remission. There was no significant difference in the age, sex, endoscopic appearance, and large cell component between the remission group and failure group. Among 66 patients with distal tumor, 65 patients (98.5%) achieved complete remission. On the other hand, among 13 patient with proximal tumor, 9 patients (69.2%) achieved complete remission (p=0.001). The odds ratio of proximal tumor for H. pylori eradication failure was 28.9 (95% CI=2.9-288.0).

CONCLUSIONS

The proximally location of MALT lymphoma is a risk factor of the H. pylori eradication treatment failure. Therefore, the proximally located gastric MALT lymphoma should be carefully treated and followed.

Treatment of gastric marginal zone lymphoma of MALT type

IMPORTANCE OF THE FIELD

Gastric marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT type) represent approximately half of all cases of lymphomas arising in the stomach. They have been strongly associated with chronic Helicobacter pylori (H. pylori) gastritis. Treatment aimed at eradicating this infection results in lymphoma remissions in the majority of patients (approximately 80%) and this represents a unique case of anticancer treatment based on the eradication of the causing factor.

AREAS COVERED IN THIS REVIEW

The effects of H. pylori eradication in suppressing the growth of this lymphoma with particular emphasis on the long-term disease control results are presented in this review. Trials of different treatment modalities for patients not responding to antibiotics are also covered.

WHAT THE READER WILL GAIN

Understanding of the effects of H. pylori eradication on suppressing the growth of gastric MALT lymphoma. Readers will learn how to distinguish between clinical, histological and molecular remission of the lymphoma and will learn alternative treatments for patients with H. pylori-negative disease and for cases not responding to eradication.

TAKE HOME MESSAGE

Gastric MALT lymphoma has an indolent course and most patients can achieve durable disease control after only anti-H. pylori therapy. For patients not responding to antibiotics, randomized trials are needed to define the best treatment modality.

Primary low-grade and high-grade gastric MALT-lymphoma presentation

GOAL

To assess the clinical and endoscopic presentation of primary gastric lymphoma.

BACKGROUND

Remission rate and long-term survival in patients with gastric lymphoma mainly depend on disease stage at diagnosis. Series reporting clinical and endoscopic presentation of gastric lymphoma are generally small and heterogeneous.

STUDY

Systematic review with pooled-data analysis assessing clinical and endoscopic presentation of primary gastric lymphoma.

RESULTS

Data regarding 2000 patients were collected. Overall, males were slightly more prevalent, alarm symptoms were absent in near half of the patients, lymphoma was diagnosed in a stage >I in one-third of the patients, and Helicobacter pylori infection was present in 88.8% of considered patients. At endoscopy, the ulcerative type was the most frequent presentation, although low-grade lymphoma was diagnosed on normal/hyperemic gastric mucosa in 9% of cases. Patients with high-grade lymphoma presented alarm symptoms (anemia and/or melena and/or hemorrhage, persistent vomiting, weight loss), an exophytic or ulcerative lesion, a stage III-IV, and a H. pylori negative status more frequently than low-grade lymphoma cases.

CONCLUSIONS

Our pooled-data analysis showed that gastric lymphoma is still disappointingly diagnosed in an advanced stage in a large number of patients. This is probably due to presence of nonspecific symptoms at initial clinical presentation and/or a normal appearing mucosa at endoscopic observation in the early stages.

Guidelines for the management of Helicobacter pylori infection in Japan: 2009 revised edition

BACKGROUND

Over the past few years, the profile of Helicobacter pylori infection has changed in Japan. In particular, the relationship between H. pylori and gastric cancer has been demonstrated more clearly. Accordingly, the committee of the Japanese Society for Helicobacter Research has revised the guidelines for diagnosis and treatment of H. pylori infection in Japan.

MATERIALS AND METHODS

Four meetings of guidelines preparation committee were held from July 2007 to December 2008. In the new guidelines, recommendations for treatment have been classified into five grades according to the Minds Recommendation Grades, while the level of evidence has been classified into six grades. The Japanese national health insurance system was not taken into consideration when preparing these guidelines.

RESULTS

Helicobacter pylori eradication therapy achieved a Grade A recommendation, being useful for the treatment of gastric or duodenal ulcer, for the treatment and prevention of H. pylori-associated diseases such as gastric cancer, and for inhibiting the spread of H. pylori infection. Levels of evidence were determined for each disease associated with H. pylori infection. For the diagnosis of H. pylori infection, measurement of H. pylori antigen in the feces was added to the tests not requiring biopsy. One week of proton-pump inhibitor-based triple therapy (including amoxicillin and metronidazole) was recommended as second-line therapy after failure of first-line eradication therapy.

CONCLUSION

The revised Japanese guidelines for H. pylori are based on scientific evidence and avoid the administrative restraints that applied to earlier versions.

Effects of Helicobacter pylori eradication on early stage gastric mucosa-associated lymphoid tissue lymphoma

BACKGROUND & AIMS

Different remission rates of gastric low-grade, B-cell, mucosa-associated lymphoid tissue (MALT) lymphoma have been reported after Helicobacter pylori eradication. We assessed the long-term remission and relapse rates of early stage MALT lymphoma in patients treated only by H pylori eradication and identified factors that might predict outcome.

METHODS

This systematic review analyzed data from 32 studies, including 1408 patients.

RESULTS

The MALT lymphoma remission rate was 77.5% (95% confidence interval, 75.3-79.7), and was significantly higher in patients with stage I than stage II(1) lymphoma (78.4% vs 55.6%; P = .0003) and in Asian than in Western groups (84.1% vs 73.8%; P = .0001). Neoplasia confined to the submucosa regressed more frequently than that with deeper invasion (82.2% vs 54.5%; P = .0001); patients with lymphoma localized to the distal stomach experienced regression more frequently than those with lymphoma of the proximal stomach (91.8% vs 75.7%; P = .0037). The remission rate was higher among patients without the API2-MALT1 translocation than in those with this translocation (78% vs 22.2%; P = .0001). In an analysis of data from 994 patients, 7.2% experienced lymphoma relapse during 3253 patient-years of follow-up evaluation, with a yearly recurrence rate of 2.2%. Infection and lymphoma were cured by additional eradication therapy in all patients with H pylori recurrence (16.7%). Five (0.05%) of the patients initially cured of lymphoma developed high-grade lymphoma within 6 to 25 months of therapy.

CONCLUSIONS

H pylori eradication is effective in treating approximately 75% of patients with early stage gastric lymphoma. Long-term follow-up evaluation of these patients is needed to detect early lymphoma relapse or progression.

Eradication therapy for Helicobacter pylori in patients with gastric MALT lymphoma: a pooled data analysis

OBJECTIVES

Helicobacter pylori eradication is recognized as the initial therapy for gastric low-grade, B-cell, mucosa-associated lymphoid tissue (MALT) lymphoma. This study assesses (i) the H. pylori eradication rates for various first- and second-line and rescue therapies and (ii) the associated reinfection rates in patients.

METHODS

Pooled data analysis of systematic review of the literature was performed in this study.

RESULTS

Data from 34 studies with 1,271 treated patients were used. After first-line therapy, the infection was cured in 91% (95% confidence interval (CI)=89.4-92.5) of cases, the eradication rate being higher after dual therapy compared with the 7- or 14-day triple therapies (P=0.0525). After second-line therapy, the eradication rate was 80.8% (95% CI=82.7-95.1), being higher after triple rather than quadruple therapy. Further therapies (from three to five attempts) cured the infection in 75% of patients. H. pylori infection was ultimately cured in 1,250 patients, resulting in eradication rates of 98.3% (95% CI=97.6-99) and 99.8% (95% CI=99.6-100) at intention-to-treat and per-protocol analysis levels, respectively. Bacterial reinfection occurred in 18 (2.7%; 95% CI=1.4-3.9) of 676 patients who were followed-up (0.7% yearly). Overall, gastric lymphoma remission was achieved in 973 (77.8%) of 1,250 patients successfully cured of H. pylori infection.

CONCLUSIONS

This was the first comprehensive ( approximately 1,300 patients) analysis of the therapeutic management of H. pylori in gastric lymphoma patients. Data suggest that this infection is easily managed in these patients, being cured in nearly all cases.

Long-term clinical outcome of helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphoma is comparable to that of h. pylori-positive lymphoma

GOALS AND BACKGROUND

Little is still known regarding the clinical features and prognosis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma without Helicobacter pylori (H. pylori) infection.

STUDY

From January 1996 to April 2006, a total of 185 patients with gastric MALT lymphoma were enrolled at Seoul National University Hospital. To assess the differences in clinical characteristics and long-term outcomes between H. pylori-negative (n=29, 15.7%) and H. pylori-positive (n=156, 84.3%) cases, we compared these 2 types of lymphoma.

RESULTS

The overall median follow-up period was 39 months. There were no significant differences between the 2 groups in terms of age, macroscopic phenotype, or histologic grade. H. pylori-negative group showed male predominancy (72.4%) and higher percentage of proximal stomach location (62.1%). Although H. pylori-negative lymphomas were more frequently presented as advanced disease (stage IIE or IV, 37.9%), no significant differences in both the overall complete response and overall survival rates were observed between the 2 groups.

CONCLUSIONS

Our results suggest that H. pylori-negative gastric MALT lymphoma shows a favorable long-term outcome, which is comparable to that of H. pylori-positive lymphoma.

Treatment of low-grade gastric MALT-lymphoma unresponsive to Helicobacter pylori therapy: a pooled-data analysis

The most favourable therapeutic strategy for gastric MALT-lymphoma not responding to Helicobacter pylori eradication still remains unclear, neither official guidelines nor randomised studies being available. We therefore performed a systematic review of the literature to evaluate the efficacy of different therapeutic approaches in these patients. Data regarding 315 patients were valuable, and lymphoma remission following the first therapeutic attempt was achieved in 90.1% cases. The most used therapy was radiotherapy (112 patients), followed by surgery (80 patients) and chemotherapy (68 patients), whilst a combination therapy was less frequent. Radiotherapy achieved a higher remission rate as compared to chemotherapy (97.3 vs. 85.3%; P = 0.007), being similar to surgery (97.3 vs. 92.5%; P = 0.2). No difference emerged when comparing lymphoma remission rate achieved by a single therapy with that of combined treatments (89.6 vs. 96.4%; P = 0.6). This is the first pooled-data analysis assessing the efficacy of different oncologic therapeutic approaches to treat gastric MALT-lymphoma unresponsive to H. pylori eradication. Radiotherapy seems to be the most suitable treatment in these patients.

Long-term outcome following Helicobacter pylori eradication in a retrospective study of 105 patients with localized gastric marginal zone B-cell lymphoma of MALT type

BACKGROUND

Treatment aimed at eradicating Helicobacter pylori infection results in lymphoma remission in most localized gastric mucosa-associated lymphoid tissue (MALT) lymphomas. The aim of this survey is to investigate the long-term effect of this therapeutic approach in a large series of patients.

METHODS

One hundred and five patients with localized gastric MALT lymphoma were initially treated only with H. pylori eradication regimens. Lymphoma responses were graded using the Wotherspoon score.

RESULTS

Helicobacter pylori, detected by histology in 81% of cases, was eradicated in all positive patients. Histological regression of the lymphoma was achieved in 78 of 102 assessable patients [76%, 95% confidence interval (CI): 67% to 84%] with complete remission (score 0-2) in 66 and partial remission (score 3) in 12. At a median follow-up time of 6.3 years, histological remission was consistently confirmed in 33 of 74 assessable patients, while 25 had score fluctuations (from 0 to 4) and 13 presented a lymphoma relapse (score 5). Only one patient had a distant progression. Transformation to a large-cell lymphoma was seen in two cases. The 5- and 10-year overall survival is 92% (95% CI: 84% to 96%) and 83% (95% CI: 70% to 91%), respectively. Only one patient died of lymphoma after transformation to a high-grade lymphoma.

CONCLUSIONS

Helicobacter pylori eradication resulted in complete lymphoma remission in the majority of cases. Long-term clinical disease control was achieved in most patients. A watch and wait policy appears to be safe in patients with minimal residual disease or histological-only local relapse.

Helicobacter and gastric malignancies

Over the past year Helicobacter pylori has been confirmed as the most important risk factor for non-cardia gastric adenocarcinomas and gastric mucosa-associated lymphoid tissue (MALT) lymphomas. Eradication therapy has been proven to be beneficial when given prior to the development of intestinal metaplasia, but is less efficacious when administered later. However, the best data from clinical trials indicate that H. pylori eradication alone will have only a moderate effect on gastric cancer incidence worldwide. The mechanisms responsible for H. pylori-associated gastric carcinogenesis continue to be dissected. Accumulating evidence suggests that some H. pylori may be able to invade through the gastric epithelial barrier, though pro-carcinogenic effects may also be related to the complex and evolving pathways of altering signal transduction pathways within gastric epithelial cells that are stimulated by adherence and translocation of H. pylori products through its type IV secretory system. Determinants of the host response to H. pylori infection continue to focus on polymorphisms in genes related to the innate and acquired immune responses, including NOD2, COX-2, and TLR-4. H. pylori eradication is indicated for low-grade gastric B-cell MALT lymphoma and may even provide "cure" in some apparently H. pylori-negative cases. How and why does H. pylori promote lymphomagenesis? Some evidence from human and murine models points to specific chromosomal translocations and host genetic polymorphisms as relating to the outcome of infection. Finally, Helicobacter hepaticus infection has been linked to both intestinal and breast tumorigenesis in susceptible strains of female mice - a provocative and novel finding warranting further investigation.