Helicobacter pylori and mucosa-associated lymphoid tissue: what's new

Cooperative participation of CagA and NFATc1 in the pathogenesis of antibiotics-responsive gastric MALT lymphoma

BACKGROUND

This study aimed to explore whether cytotoxin-associated gene A (CagA) can inhibit cell cycle progression by activating nuclear factor of activated T cells (NFAT) in lymphoma B cells and contribute to Helicobacter pylori eradication (HPE) responsiveness (complete remission [CR] after HPE) in gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

MATERIALS AND METHODS

We co-cultured three B-lymphoma cell lines (MA-1, OCI-Ly3, and OCI-Ly7) with HP strains (derived from HPE-responsive gastric MALT lymphoma) and evaluated the expression patterns of CagA, phosphorylated (p)-CagA (CagAP-Tyr), and CagA-signaling molecules, cell-cycle inhibitors, p-NFATc1 (Ser172), and NFATc1 using western blotting. Furthermore, we evaluated the association between nuclear NFATc1 expression in the tumor cells of 91 patients who received first-line HPE (59 patients with HPE responsiveness and 32 without HPE responsiveness) and HPE responsiveness and CagA expression in tumor cells.

RESULTS

In HP strains co-cultured with B cell lymphoma cell lines, CagA was translocated to the nucleus through tyrosine phosphorylation (CagAP-Tyr) and simultaneously dephosphorylated NFATc1, subsequently causing nuclear NFATc1 translocation and stimulating the expression of p-SHP-2/p-ERK/Bcl-xL. Activated NFATc1 causes G1 cell cycle retardation in both MA-1 and OCI-Ly3 cells by triggering p21 and p27 production. Nuclear NFATc1 localization was significantly associated with the presence of CagA in gastric MALT lymphomas (80% [41/51] vs. 33% [13/40]; p < 0.001) and with HPE responsiveness (73% [43/59] vs. 25% [8/32]; p < 0.001). Patients exhibiting both the presence of CagA and nuclear NFATc1 localization responded more rapidly to HPE than those without (median interval to CR, 4.00 vs. 6.00 months, p = 0.003).

CONCLUSIONS

Our findings indicated that CagA and NFATc1 cooperatively participate in the lymphomagenesis of HPE-responsive gastric MALT lymphoma.

Insights into the molecular mechanisms of H. pylori-associated B-cell lymphoma

Cancer research has extensively explored various factors contributing to cancer development, including chemicals, drugs, smoking, and obesity. However, the role of bacterial infections in cancer induction remains underexplored. In particular, the mechanisms underlying H. pylori-induced B-cell lymphoma, a potential consequence of bacterial infection, have received little attention. In recent years, there has been speculation about contagious agents causing persistent inflammation and encouraging B-lymphocyte transition along with lymphomagenesis. MALT lymphoma associated with chronic H. pylori infection, apart from two other central associated lymphomas - Burkitt's Lymphoma and DLBCL, is well studied. Owing to the increasing colonization of H. pylori in the host gut and its possible action in the development of B-cell lymphoma, this review aims to summarize the existing reports on different B-cell lymphomas' probable association with H. pylori infections; also emphasizing the function of the organism in lymphomagenesis; including its interaction with the host, pathogen and host-specific factors, and tumor microenvironment.

Influence of chlorpyrifos and endosulfan and their metabolites on the virulence of Helicobacter pylori

Organochlorine (OC) and organophosphorus (OP) pesticides such as chlorpyrifos (CPF) and endosulfan (ES) have been associated with a plethora of adverse health effects. Helicobacter pylori (H. pylori) infection can lead to gastrointestinal diseases by regulating several cellular processes. Thus, the current study focuses on the effect of the co-exposure to pesticides and H. pylori on gastric epithelial cells. We have used the in-silico approach to determine the interactive potential of pesticides and their metabolites with H. pylori-associated proteins. Further, various in-vitro methods depict the potential of ES in enhancing the virulence of H. pylori. Our results showed that ES along with H. pylori affects the mitochondrial dynamics, increases the transcript expression of mitochondrial fission genes, and lowers the mitochondrial membrane potential and biomass. They also promote inflammation and lower oxidative stress as predicted by ROS levels. Furthermore, co-exposure induces the multi-nucleated cells in gastric epithelial cells. In addition, ES along with H. pylori infection follows the extrinsic pathway for apoptotic signaling. H. pylori leads to the NF-κB activation which in turn advances the β-catenin expression. The expression was further enhanced in the co-exposure condition and even more prominent in co-exposure with ES-conditioned media. Thus, our study demonstrated that pesticide and their metabolites enhance the pathogenicity of H. pylori infection.

Role of the gut microbiota in hematologic cancer

Hematologic neoplasms represent 6.5% of all cancers worldwide. They are characterized by the uncontrolled growth of hematopoietic and lymphoid cells and a decreased immune system efficacy. Pathological conditions in hematologic cancer could disrupt the balance of the gut microbiota, potentially promoting the proliferation of opportunistic pathogens. In this review, we highlight studies that analyzed and described the role of gut microbiota in different types of hematologic diseases. For instance, myeloma is often associated with Pseudomonas aeruginosa and Clostridium leptum, while in leukemias, Streptococcus is the most common genus, and Lachnospiraceae and Ruminococcaceae are less prevalent. Lymphoma exhibits a moderate reduction in microbiota diversity. Moreover, certain factors such as delivery mode, diet, and other environmental factors can alter the diversity of the microbiota, leading to dysbiosis. This dysbiosis may inhibit the immune response and increase susceptibility to cancer. A comprehensive analysis of microbiota-cancer interactions may be useful for disease management and provide valuable information on host-microbiota dynamics, as well as the possible use of microbiota as a distinguishable marker for cancer progression.

The TLR/MyD88 signalling cascade in inflammation and gastric cancer: the immune regulatory network of Helicobacter pylori

Helicobacter pylori-induced chronic gastritis represents a well-established risk factor for gastric cancer (GC). However, the mechanism by which chronic inflammation caused by H. pylori induces the development of GC is unclear. H. pylori can influence host cell signalling pathways to induce gastric disease development and mediate cancer promotion and progression. Toll-like receptors (TLRs), as pattern recognition receptors (PRRs), play a key role in the gastrointestinal innate immune response, and their signalling has been implicated in the pathogenesis of an increasing number of inflammation-associated cancers. The core adapter myeloid differentiation factor-88 (MyD88) is shared by most TLRs and functions primarily in H. pylori-triggered innate immune signalling. MyD88 is envisioned as a potential target for the regulation of immune responses and is involved in the regulation of tumourigenesis in a variety of cancer models. In recent years, the TLR/MyD88 signalling pathway has received increasing attention for its role in regulating innate and adaptive immune responses, inducing inflammatory activation and promoting tumour formation. In addition, TLR/MyD88 signalling can manipulate the expression of infiltrating immune cells and various cytokines in the tumour microenvironment (TME). In this review, we discuss the pathogenetic regulatory mechanisms of the TLR/MyD88 signalling cascade pathway and its downstream molecules in H. pylori infection-induced-associated GC. The focus is to elucidate the immunomolecular mechanisms of pathogen recognition and innate immune system activation of H. pylori in the TME of inflammation-associated GC. Ultimately, this study will provide insight into the mechanism of H. pylori-induced chronic inflammation-induced GC development and provide thoughts for GC prevention and treatment strategies.

First-line antibiotic treatment in patients with localized extragastric mucosa-associated lymphoid tissue lymphoma

Between January 2010 and December 2015, we enrolled 28 patients with stage IEI/IIE1 extragastric mucosa-associated lymphoid tissue (MALT) lymphoma who received first-line antibiotic treatment, after informing them about the pros and cons of alternative therapies. In addition, during the same period, 64 patients with stage IE/IIE1 disease who received conventional treatment were selected as the control group. The most common primary sites were the ocular adnexal area (17 cases), followed by the salivary glands (four cases), pulmonary (three cases), and thyroid, trachea, larynx, and colon region (one case each). First-line antibiotic treatment resulted in an overall response rate of 57.1%: 12 patients achieved complete remission (CR), while four achieved partial remission (antibiotic-responsive tumors). Monoclonal gammopathy was significantly prevalent in antibiotic-unresponsive tumors than in antibiotic-responsive tumors (50.0% [6/12] vs. 12.5% [2/16], p = 0.044). After a median follow-up of 7 years, all patients with CR remained lymphoma-free, with 7-year event-free survival (EFS) and overall survival (OS) rates of 62.7% and 96.4%, respectively. The 7-year EFS and OS rates of patients who received conventional treatments were 73.1% and 91.1%, respectively. Compared with that noted in patients who received conventional treatment, antibiotic treatment was effective in some patients with localized extragastric MALT lymphoma.

Bacterial infection-driven lymphomagenesis

PURPOSE OF REVIEW

The first convincing evidence for a causal relationship between bacterial infection and lymphomagenesis came from the link between gastric lymphoma and chronic Helicobacter pylori gastritis. This review will summarize the current epidemiological, clinical, and biological evidence of a causative role of bacteria in the development of malignant lymphomas, particularly, the extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type.

RECENT FINDINGS

Other microorganisms have been associated with specific extranodal lymphoma sites with variable and not always definitive, evidence, including Chlamydia psittaci , Borrelia burgdorferi , Campylobacter jejuni and, most recently, Coxiella Burnetii . According to most plausible models, lymphoma growth is a consequence of continuous antigenic stimulation induced by chronic infection. However, some evidence of a direct oncogenic role of H. pylori has been provided, too.

SUMMARY

Lymphomas are not the result of a single cause but multifactorial diseases, influenced by a variety of genetic and environmental elements. Hence, ascertaining the specific contribution of bacterial infections is not always easy. Nevertheless, the eradication of the associated chronic infection may result in sustained lymphoma regression. Moreover, the association between infections and lymphoma may offer opportunities for reducing lymphoma incidence by preventing the predisposing infections or treating them early.

A New Staging System Based on the Dynamic Prognostic Nomogram for Elderly Patients With Primary Gastrointestinal Diffuse Large B-Cell Lymphoma

Objective

The purpose of this study is to establish an accurate prognostic model based on important clinical parameters to predict the overall survival (OS) of elderly patients with primary gastrointestinal diffuse large B-cell lymphoma (EGI DLBCL).

Methods

The Cox regression analysis is based on data from the Surveillance, Epidemiology, and End Results (SEER) database.

Results

A total of 1,783 EGI DLBCL cases were eligible for the study [median (interquartile range, IQR) age, 75 (68–82) years; 974 (54.63%) males], of which 1,248 were randomly assigned to the development cohort, while 535 were into the validation cohort. A more accurate and convenient dynamic prognostic nomogram based on age, stage, radiation, and chemotherapy was developed and validated, of which the predictive performance was superior to that of the Ann Arbor staging system [C-index:0.69 (95% CI:0.67–0.71) vs. 56 (95%CI:0.54–0.58); P < 0.001]. The 3- and 5-year AUC values of ROC curves for 3-year OS and 5-year OS in the development cohort and the validation cohort were were alll above 0.7.

Conclusion

We establish and validate a more accurate and convenient dynamic prognostic nomogram for patients with EGI DLBCL, which can provide evidence for individual treatment and follow-up.

Current Status of the Spectrum and Therapeutics of Helicobacter pylori-Negative Mucosa-Associated Lymphoid Tissue Lymphoma

Simple Summary

The prevalence of Helicobacter pylori (HP)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma has increased over the last two decades, whereas that of HP-positive gastric MALT lymphoma has decreased. Although the role of first-line antibiotics in the treatment of HP-negative gastric MALT lymphomas remains ambiguous, several case series have reported that a first-line HP eradication therapy (HPE)-like regimen could result in complete remission in a proportion of patients with localized HP-negative gastric MALT lymphoma. Previous sporadic reports have indicated that certain patients with extragastric MALT lymphoma can respond to first-line antibiotic treatment as well. These findings suggest that, in contrast to antibiotic-unresponsive tumors, antibiotic-responsive tumors may be recognized within the spectrum of HP-negative MALT lymphoma. In addition to conventional chemotherapy and immunochemotherapy, macrolide antibiotics and immunomodulatory drugs have been previously used and demonstrated to be efficacious. This article provides the spectrum and therapeutics for HP-negative MALT lymphoma.

Abstract

Helicobacter pylori (HP)-unrelated mucosa-associated lymphoid tissue (MALT) lymphoma includes the majority of extragastric MALT lymphomas and a small proportion of gastric MALT lymphomas. Although the role of first-line antibiotics in treating HP-negative gastric MALT lymphomas remains controversial, HP eradication therapy (HPE)-like regimens may result in approximately 20–30% complete remission (CR) for patients with localized HP-negative gastric MALT lymphoma. In these patients, H. heilmannii, H. bizzozeronii, and H. suis were detected in sporadic gastric biopsy specimens. Extragastric MALT lymphoma is conventionally treated with radiotherapy for localized disease and systemic chemotherapy for advanced and metastatic diseases. However, a proportion of extragastric MALT lymphomas, such as ocular adnexal lesions and small intestinal lesions, were reported to be controlled by antibiotics for Chlamydophila psittaci and Campylobacter jejuni, respectively. Some extragastric MALT lymphomas may even respond to first-line HPE. These findings suggest that some antibiotic-responsive tumors may exist in the family of HP-negative MALT lymphomas. Two mechanisms underlying the antibiotic responsiveness of HP-negative MALT lymphoma have been proposed. First, an HPE-like regimen may eradicate the antigens of unknown bacteria. Second, clarithromycin (the main component of HPE) may have direct or indirect antineoplastic effects, thus contributing to the CR of these tumors. For antibiotic-unresponsive HP-negative MALT lymphoma, high-dose macrolides and immunomodulatory drugs, such as thalidomide and lenalidomide, have reported sporadic success. Further investigation of new treatment regimens is warranted.

Bacterial and Parasitic Pathogens as Risk Factors for Cancers in the Gastrointestinal Tract: A Review of Current Epidemiological Knowledge

The oncogenic potential of viral infections is well established and documented for many years already. However, the contribution of (commensal) bacteria and parasites to the development and progression of cancers has only recently gained momentum, resulting in a rapid growth of publications on the topic. Indeed, various bacteria and parasites have been suggested to play a role in the development of gastrointestinal cancer in particular. Therefore, an overview of the current epidemiological knowledge on the association between infections with bacteria and parasites and cancers of the gastrointestinal tract is needed. In this review, we summarized the methodological characteristics and main results of epidemiological studies investigating the association of 10 different bacteria (Bacteroides fragilis, Campylobacter spp., Clostridium spp., Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Porphyromonas gingivalis, non-typhoidal Salmonella, Salmonella Typhi, and Streptococcus spp.) and three parasites (Cryptosporidium spp., Schistosoma spp., and Strongyloides stercoralis) with gastrointestinal cancer. While the large body of studies based on microbiome sequencing provides valuable insights into the relative abundance of different bacterial taxa in cancer patients as compared to individuals with pre-malignant conditions or healthy controls, more research is needed to fulfill Koch's postulates, possibly making use of follow-up data, to assess the complex role of bacterial and parasitic infections in cancer epidemiology. Studies incorporating follow-up time between detection of the bacterium or parasite and cancer diagnosis remain valuable as these allow for estimation of cause-effect relationships.

Distribution pattern and prevalence of haematological cancers among adults in Abakaliki, South-Eastern Nigeria

Background

Haematological cancers are clonal diseases of the blood and blood-forming organs, with the distribution pattern not known in our locality. This study aimed to describe the distribution pattern and prevalence of haematological cancers among adults in Abakaliki, Nigeria.

Materials and Methods

This was an 8-year retrospective study in which the hospital records/case notes of adult patients diagnosed and managed for haematological cancers from May 2012 to April 2020 were reviewed. Data obtained were analysed with the SPSS software, version 20.

Results

One hundred and thirty-five cases of haematological cancers were included in the study, with 72 (53.4%) males and 63 (46.6%) females and male-to-female ratio of 1.1:1. The age range was 18-82 years, with a mean age of 49 ± 17 years. Lymphoid malignancies predominate more than myeloid (101 [74.8%] vs. 34 [25.2%]). The leukaemias were more predominant than the lymphomas and myeloma accounting for 48.2%, 36.3% and 7.4%, respectively. Chronic leukaemias were more common than the acute leukaemias with chronic lymphocytic leukaemia (CLL) being the most common accounting for 24.4% of haematological cancers. In general, non-Hodgkin's lymphoma (NHL) was the most common haematologic cancer accounting for 35 (25.9%), followed by CLL 33 (24.4%), chronic myeloid leukaemia (CML) 17 (12.6%), Hodgkin's lymphoma (HL) 14 (10.4%) and multiple myeloma (MM) 10 (7.4%). Others include acute lymphoblastic leukaemia (ALL) 9 (6.7%) and acute myeloblastic leukaemia (AML) 6 (4.4%). Myelodysplastic syndrome (MDS) and polycythaemia vera (PV), each contributed 3% while myelofibrosis (MF) and essential thrombocythaemia (ET) contributed 1.5% and 0.7%, respectively.

Conclusion

This study has shown that haematological cancers are not uncommon in our locality with NHL being the most common, followed by CLL, CML, HL, MM, ALL, AML, MDS, PV. MF and ET in that order. The burden of haematological cancers in Ebonyi State, Nigeria is therefore significant and should be prioritised in health-care policy formulation and management.

MALT lymphoma of the tongue: An unusual site that may present a diagnostic challenge

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a low-grade B cell lymphoma that can affect any organ, usually preceded by acquisition of MALT in response to antigenic stimulus provided by infections or autoimmune diseases. Most often, MALT lymphoma involves the stomach (about 35% of cases), followed by the ocular adnexal region, skin, lungs, and salivary glands, but virtually any extranodal site can be involved. MALT lymphomas are less common at sites of normal MALT tissue, such as Waldeyer ring and the ileocecal region of the gastrointestinal tract. Lymphomas involving the tongue are extremely rare and represent approximately 3% of all lymphomas involving the head and neck region. In this study, we discuss potentially challenging diagnostic aspects of MALT lymphoma involving the tongue and review and summarize the available literature about this topic.

Primary gastric non-Hodgkin lymphomas: Recent advances regarding disease pathogenesis and treatment

Primary gastric lymphomas (PGLs) are distinct lymphoproliferative neoplasms described as heterogeneous entities clinically and molecularly. Their main histological types are diffuse large B-cell lymphoma (DLBCL) or mucosa-associated lymphoma tissue. PGL has been one of the main fields of clinical research of our group in recent years. Although gastric DLBCLs are frequent, sufficient data to guide optimal care are scarce. Until today, a multidisciplinary approach has been applied, including chemotherapy, surgery, radiotherapy or a combination of these treatments. In this minireview article, we provide an overview of the clinical manifestations, diagnosis and staging of these diseases, along with their molecular pathogenesis and the most important related clinical published series. We then discuss the scientific gaps, perils and pitfalls that exist regarding the aforementioned studies, in parallel with the unmet need for future research and comment on the proper methodology for such retrospective studies. Aiming to fill this gap, we retrospectively evaluated the trends in clinical presentation, management and outcome among 165 patients with DLBCL PGL who were seen in our institutions in 1980-2014. The study cohort was divided into two subgroups, comparing the main 2 therapeutic options [cyclophosphamide doxorubicin vincristine prednisone (CHOP) vs rituximab-CHOP (R-CHOP)]. A better outcome with immunochemotherapy (R-CHOP) was observed. In the next 2 mo, we will present the update of our study with the same basic conclusion.

Reconsidering the "protective" hypothesis of Helicobacter pylori infection in eosinophilic esophagitis

Since its discovery, Helicobacter pylori (H. pylori) has attracted attention in the biomedical world with its numerous pathophysiologic implications, both gastrointestinal and systemic. Beyond its well-established carcinogenic properties, emerging evidence also supports "harmful" proinflammatory and neurodegenerative roles of H. pylori. On the other hand, H. pylori infection has been proposed to be "protective" against several diseases, such as asthma and gastroesophageal reflux disease. Eosinophilic esophagitis (EoE) is a relatively new, allergen/immune-mediated disease, which has also been linked to these considerations. Main arguments are a postulated shift of immune responses by H. pylori from T helper 2 (T_H 2) to T_H 1 polarization, as well as a potential decline of the H. pylori burden with the dramatic parallel rise of ΕοΕ: a series of observational studies reported an inverse association. In this review, we counter these arguments by providing further epidemiological data, which point out that this generalization might be rather incomplete. We also discuss the limitations of the existing studies evaluating a possible association. Furthermore, we provide current evidence on common pathogenetic components, which share both entities. In summary, the claim that H. pylori is protective against EoE is rather incomplete, and further mechanistic studies are necessary to elucidate a possible association.

Putative role of marginal zone B cells in pathophysiological processes

The maintenance of inner integrity of an organism is founded on the proper performance of two immunity branches, innate and adaptive immune responses. Recently, it became apparent that subset of splenic B cells named marginal zone B cells (MZB cells) exhibits unique developmental and functional features that bridge these two immunity branches. Strategically positioned at the site where blood and lymph are filtered, MZB cells represent a population of sentinels that rapidly proliferate and differentiate into IgM plasmablast cells when encountered with blood-borne, thymus-independent (TI) Ags. Moreover, MZB cells have intrinsic capability to induce potent CD4⁺ helper T cell response and cytokine production upon stimulation with soluble antigens. Due to their ability to overcome a time gap prior the establishment of the full adaptive response towards pathogens, MZB cells connect and direct innate and adaptive immunity. An additional interesting characteristic of MZB cells is capacity to function as regulatory cells in autoimmune processes. MZB cells may also contribute to the control of autoimmunity via the induction of tolerance by apoptotic cells. Importantly, in the clear association with inflammation and autoimmunity, MZB cells may transform into MALT lymphoma, representing a concurrence point for the infection, immunity and malignancy. This paper presents an insight into the complex biology of marginal zone B cells and their role in intertwining and directing innate and adaptive immune processes at the physiological and pathological level.

Bovine lactoferrin enhances the efficacy of levofloxacin-based triple therapy as first-line treatment of Helicobacter pylori infection: an in vitro and in vivo study

Objectives

To evaluate the in vitro antimicrobial/antivirulence action of bovine lactoferrin and its ability to synergize with levofloxacin against resistant Helicobacter pylori strains and to analyse the effect of levofloxacin, amoxicillin and esomeprazole with and without bovine lactoferrin as the first-line treatment for H. pylori infection.

Methods

The bovine lactoferrin antimicrobial/antivirulence effect was analysed in vitro by MIC/MBC determination and twitching motility against six clinical H. pylori strains and a reference strain. The synergism was evaluated using the chequerboard assay. The prospective therapeutic trial was carried out on two separate patient groups, one treated with esomeprazole/amoxicillin/levofloxacin and the other with esomeprazole/amoxicillin/levofloxacin/bovine lactoferrin. Treatment outcome was determined with the [¹³C]urea breath test.

Results

In vitro, bovine lactoferrin inhibited the growth of 50% of strains at 10 mg/mL and expressed 50% bactericidal effect at 40 mg/mL. The combination of levofloxacin and bovine lactoferrin displayed a synergistic effect for all strains, with the best MIC reduction of 16- and 32-fold for levofloxacin and bovine lactoferrin, respectively. Bovine lactoferrin at one-fourth MIC reduced microbial motility significantly for all strains studied. In the in vivo study, 6 of 24 patients recruited had treatment failure recorded with esomeprazole/amoxicillin/levofloxacin (75% success, 95% CI 57.68%–92.32%), and in the group with esomeprazole/amoxicillin/levofloxacin/bovine lactoferrin, 2 out of 53 patients recruited had failure recorded (96.07% success, 95% CI 90.62%–101.38%).

Conclusions

Bovine lactoferrin can be considered a novel potentiator for restoring susceptibility in resistant H. pylori strains. Bovine lactoferrin added to a triple therapy in first-line treatment potentiates the therapeutic effect.

Association between Active Helicobacter pylori Infection and Glaucoma: A Systematic Review and Meta-Analysis

Background: Glaucoma is the second most common cause of blindness worldwide affecting almost 70 million individuals. Helicobacter pylori (H. pylori) is a widespread pathogen with systematic pathogenicity. This meta-analysis aimed to estimate the contradictory data regarding a potential association between active H. pylori infection and glaucoma. Materials and Methods: A research in MEDLINE/PubMed and Google Scholar was conducted and original studies investigating the relationship between H. pylori infection and glaucoma were included. Analysis was performed with random effects model. The main outcome was the odds ratio (OR) with 95% confidence intervals (CI) of H. pylori infection as a risk factor for glaucoma. A parallel analysis studied the role of active infection as indicated by histology and the titer of anti-H. pylori antibodies. For the anti-H. pylori antibody titers, weighted mean differences (WMD) were estimated between patients and controls. Results: Fifteen studies were included, with 2664 participants (872 patients with glaucoma and 1792 controls), divided into primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) and pseudo-exfoliation glaucoma (PEG). The association between H. pylori infection and overall glaucoma was significant (OR = 2.08, CI 95% 1.48–2.93) with moderate heterogeneity (I² = 61.54%). After stratification by glaucoma subtype, heterogeneity was eliminated in the NTG subgroup. Studies with healthy controls, and controls with anemia yielded very low or no heterogeneity, respectively. Gastric biopsy to document active H. pylori infection yielded the highest OR (5.4, CI: 3.17–9.2, p < 0.001) and null heterogeneity. For anti-H. pylori antibody titers, there was a significant difference in WMD between patients and controls (WMD 15.98 IU/mL; 95% CI: 4.09–27.87; p = 0.008); values were greater in glaucoma patients, with high heterogeneity (I²: 93.8%). Meta-regression analysis showed that mean age had a significant impact on glaucoma (p = 0.037). Conclusions: Active H. pylori infection may be associated with glaucoma with null heterogeneity, as, beyond histology, quantified by anti-H. pylori titers and increases with age.

Microbe-MUC1 Crosstalk in Cancer-Associated Infections

Infection-associated cancers account for ∼20% of all malignancies. Understanding the molecular mechanisms underlying infection-associated malignancies may help in developing diagnostic biomarkers and preventative vaccines against malignancy. During infection, invading microbes interact with host mucins lining the glandular epithelial cells and trigger inflammation. MUC1 is a transmembrane mucin glycoprotein that is present on the surface of almost all epithelial cells, and is known to interact with invading microbes. This interaction can trigger pro- or anti-inflammatory responses depending on the microbe and the cell type. In this review we summarize the mechanisms of microbe and MUC1 interactions, and highlight how MUC1 plays contrasting roles in different cells. We also share perspectives on future research that may support clinical advances in infection-associated cancers.

Association Between Gastric Lymphoid Follicles (Precursor Of MALT Lymphomas) And H. pylori Infection At A Referral Hospital In Iran

Purpose

Mucosa-associated lymphoid tissue (MALT) is the most common endoscopic finding in Helicobacter pylori positive patients that can progress to MALT lymphoma after a prolonged antigenic contact. This study was aimed to evaluate the prevalence of lymphoid follicles and aggregates (precursors of MALT lymphomas) in gastric mucosal biopsies and their correlation with H. pylori infection.

Patients and methods

In this study, 100 patients who had undergone an upper gastrointestinal endoscopy were enrolled. Five biopsy specimens were taken each patient through screening endoscopy and histopathological changes were evaluated and graded using the Wotherspoon System. The clinical background and H. pylori infection status were also investigated.

Results

Among the 100 cases in our series, 79 patients (79%) showed evidence of MALT in at least one biopsy specimen taken from the stomach and 21 cases (21%) had no evidence of MALT. H. pylori infection was detected in 74 (74%) patients. Lymphoid follicles were detected more frequently in H. pylori-positive patients (59%) compared to H. pylori-negative cases (3%) (P<0.001).

Conclusion

The frequency of lymphoid follicles and aggregates in gastric mucosal is associated with H. pylori infection. Further community-based studies in larger sample sizes using a combination of microscopic methods and PCR assay are required for effective monitoring of H. pylori infection.

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 Impact of Surgery on Long-Term Survival of Patients with Primary Gastric Diffuse Large B-Cell Lymphoma: A SEER Population-Based Study

Background

The aim of this retrospective study was to compare the long-term survival of patients receiving conservative with surgical treatment to analyze the prognostic factors and the impact of surgery on oncological outcomes of patients with primary gastric diffuse large B-cell lymphoma.

Methods

A total of 2647 patients diagnosed with primary gastric diffuse large B-cell lymphoma from 1998 to 2014 were extracted from SEER database. Propensity matching was performed to compare the clinicopathological characteristics of the two groups. Based on the recursive partitioning analysis, the patients were divided into three risk subgroups: low risk, intermediate risk, and high risk.

Results

After propensity score matching, patient characteristics did not differ significantly between the two groups. The 5-year cancer-specific survival rates of the surgical group and the conservative treatment group were, respectively, 60% and 59.2% (P = 0.952) before propensity matching and 64.2% and 58.6% (P = 0.046) after propensity matching. According to the multivariate analysis, age, tumor stage, and chemotherapy and surgery were independent risk factors for long-term survival. The 5-year cancer-specific survival rates differed significantly between the low-risk, intermediate-risk, and high-risk patients (76.2% vs. 57.4% vs. 25.5%, respectively, P < 0.001). The 5-year cancer-specific survival rate of the surgical group was significantly higher than that of the conservative treatment group in the low-risk patients. However, it did not differ significantly in the intermediate-risk and high-risk patients (P > 0.05).

Conclusions

A prognostic model was constructed based on the independent risk factors of age, tumor stage, and chemotherapy. The prognostic model indicated that low-risk patients (age < 75 years, stage I/II, with/without chemotherapy) undergoing surgical treatment may benefit from long-term survival, while intermediate- and high-risk patients (age ≥ 75 years, stage I/II, with/without chemotherapy or III/IV patients, with/without chemotherapy) gain no significant benefit from surgery.

Treatment Strategies and Prognostic Factors of Primary Gastric Diffuse Large B Cell Lymphoma: A Retrospective Multicenter Study of 272 Cases from the China Lymphoma Patient Registry

Background: The respective and combinatorial roles of surgery, Rituximab and chemotherapy in primary gastric diffuse large B cell lymphoma (PGDLBCL) therapy remained unclear. The purpose of the study was to evaluate present treatment strategies and prognostic factors of PGDLBCL. Methods: 272 cases (from 1994-1 to 2015-12) were retrospectively analyzed. According to the therapy regimen, patients were classified into four groups: chemotherapy (C), chemotherapy + surgery (C+S), Rituximab + chemotherapy (R+C), and Rituximab + chemotherapy + surgery (R+C+S). Results: The 3-year progression-free survival (PFS) and 3-year overall survivals (OS) of the entire cohort were 77.0% and 81.2% respectively (median follow-up time: 44.3 months). Survival of surgery-treated patients was superior to the survival of those receiving drug therapy alone (PFS: 82.6% vs. 74.7%, p=0.015; OS: 87.8% vs. 78.6%, p=0.036). Rituximab showed significant clinical benefit in OS (87.1% vs. 75.0%, p=0.007), especially in advanced-stage or high risk (IPI 3-5) patients. Group C had the lowest PFS and OS among the four groups, while the survival of other three groups were similar (Group C vs. Group C+S vs. Group R+C vs. Group R+C+S: 3-year PFS: 67.2% vs. 81.4% vs. 81.2% vs. 81.8%, p=0.002; 3-year OS: 68.4% vs. 85.4% vs. 87.2% vs. 88.6%, p<0.001). Multivariate analysis showed that IPI and therapy regimens were highly predictive for both PFS and OS. Conclusions: Our results suggested that the combinations of chemotherapy and surgery, or chemotherapy and Rituximab, are superior to other treatment strategies for PGDLBCL. IPI and therapy regimens are independent predictors of outcomes. Future prospective trial is warranted.

Extranodal lymphomas in the public health system in Chile: Analysis of 1251 patients from the National Adult Cancer Program

The aim of the study was to describe the clinical and epidemiological characteristics, anatomic and histologic distribution, and treatment results of extranodal lymphomas (ENLs), diagnosed and treated in the public health system in Chile. We included patients with ENL diagnosed from 1998 to 2014, in 17 cancer centers, registered prospectively in the database of the National Adult Cancer Program (PANDA) of the Ministry of Health. Treatment was based on the local protocols for each lymphoma subtype. Extranodal lymphoma was documented in 1215 of 4907 non-Hodgkin lymphomas diagnosed in that period (25%). Median age was 59 years (range, 16-95), and 55% were female. The gastrointestinal (GI) tract was the most common location (38%), followed by the head and neck (24%) and the skin (15%). B-cell lymphomas accounted for 78% of cases, diffuse large B-cell lymphoma being the most common histologic subtype (68%). Mycosis fungoides/Sezary syndrome was the most frequent T-cell subtype (36%), followed by NK/T-cell lymphomanasal type (24%). In comparison with western countries, Chile showed a significantly high prevalence of NK/T-cell lymphoma nasal type, while the frequency of B-cell ENL and the anatomic distribution appeared similar, being GI the most commonly involved site.

Management of relapsed/refractory marginal zone lymphoma: focus on ibrutinib

Marginal zone lymphomas (MZLs) consist of a diverse family of malignancies, which are derived from B-cells. The disease subtypes are recognized extranodal, nodal, and splenic MZLs. The disease characteristics, clinical course, and treatment vary considerably based on the site of involvement. In 2017, the US Food and Drug Administration approved ibrutinib, a first in class Bruton’s tyrosine kinase inhibitor that revolutionized the care of chronic lymphocytic leukemia patients; for, the treatment of relapsed/refractory MZL based on pivotal open-label Phase II trial demonstrated an overall response rate of 48%, with a complete response rate of 3%, median progression-free survival of 14.2 months, and median overall survival not yet reached at a median follow-up of 19.4 months. In this review, we aim to summarize the current conundrums in the management of MZL and the evolving role of ibrutinib in the treatment of MZL.

Increased colon cancer risk after severe Salmonella infection

BACKGROUND

Colon cancer constitutes one of the most frequent malignancies. Previous studies showed that Salmonella manipulates host cell signaling pathways and that Salmonella Typhimurium infection facilitates colon cancer development in genetically predisposed mice. This epidemiological study examined whether severe Salmonella infection, usually acquired from contaminated food, is associated with increased colon cancer risk in humans.

METHODS AND FINDINGS

We performed a nationwide registry-based study to assess colon cancer risk after diagnosed Salmonella infection. National infectious disease surveillance records (1999-2015) for Dutch residents aged ≥20 years when diagnosed with salmonellosis (n = 14,264) were linked to the Netherlands Cancer Registry. Salmonella-infected patients were laboratory-confirmed under medical consultation after 1-2 weeks of illness. These datasets also contained information on Salmonella serovar and type of infection. Colon cancer risk (overall and per colon subsite) among patients with a diagnosed Salmonella infection was compared with expected colon cancer risk in the general population. Data from the nationwide registry of histo- and cytopathology (PALGA) and Statistics Netherlands (CBS) allowed assessing potential effects of age, gender, latency, socioeconomic status, genetic predisposition, inflammatory bowel disease (IBD), and tumor features. We found that compared to the general population, colon cancer risk was significantly increased (standardized incidence ratio [SIR] 1.54; 95%CI 1.09-2.10) among patients with Salmonella infection diagnosed <60 years of age. Such increased risk concerned specifically the ascending/transverse colon (SIR 2.12; 95%CI 1.38-3.09) after S. Enteritidis infection (SIR 2.97; 95%CI 1.73-4.76). Salmonellosis occurred more frequently among colon cancer patients with pre-infectious IBD, a known risk factor for colon cancer. Colon tumors of patients with a history of Salmonella infection were mostly of low grade.

CONCLUSIONS

Patients diagnosed with severe salmonellosis have an increased risk of developing cancer in the ascending/transverse parts of the colon. This risk concerns particularly S. Enteritidis infection, suggesting a contribution of this major foodborne pathogen to colon cancer development.

First-line antibiotic therapy in Helicobacter pylori-negative low-grade gastric mucosa-associated lymphoid tissue lymphoma

First-line antibiotic treatment for eradicating Helicobacter pylori (HP) infection is effective in HP-positive low-grade gastric mucosa-associated lymphoid tissue lymphoma (MALToma), but its role in HP-negative cases is uncertain. In this exploratory retrospective study, we assessed the outcome and potential predictive biomarkers for 25 patients with HP-negative localized gastric MALToma who received first-line HP eradication (HPE) therapy. An HP-negative status was defined as negative results on histology, rapid urease test, ¹³C urea breath test, and serology. We observed an antibiotic response (complete remission [CR], number = 8; partial remission, number = 1) in 9 (36.0%) out of 25 patients. A t(11;18)(q21;q21) translocation was detected in 7 (43.8%) of 16 antibiotic-unresponsive cases, but in none of the 9 antibiotic-responsive cases (P = 0.027). Nuclear BCL10 expression was significantly higher in antibiotic-unresponsive tumors than in antibiotic-responsive tumors (14/16 [87.5%] vs. 1/9 [11.1%]; P = 0.001). Nuclear NF-κB expression was also significantly higher in antibiotic-unresponsive tumors than in antibiotic-responsive tumors (12/16 [75.0%] vs. 1/9 [11.1%]; P = 0.004). A substantial portion of patients with HP-negative gastric MALToma responded to first-line HPE. In addition to t(11;18)(q21;q21), BCL10 and NF-κB are useful immunohistochemical biomarkers to predict antibiotic-unresponsive status in this group of tumors.

A Rare Case of Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma Transforming into Diffuse Large B-Cell Lymphoma

Mucosa-associated lymphoid tissue lymphoma (MALToma) is a low grade B-cell lymphoma that develops from the lungs, intestinal tract, salivary gland, and other organs and is included under extranodal marginal zone lymphoma. When a primary pulmonary MALToma develops from bronchus-associated lymphoid tissue (BALT), it is called BALT lymphoma (BALToma). The etiology of MALToma is not clear; however, an association between chronic inflammatory conditions and BALToma has been observed. Transformation of MALToma to high grade lymphoma is very rare. We experienced a case of MALToma that had developed from the lungs in a patient who was undergoing treatment for latent tuberculosis and rapidly transformed into high grade B-cell lymphoma.

The B-cell-activating factor signalling pathway is associated with Helicobacter pylori independence in gastric mucosa-associated lymphoid tissue lymphoma without t(11;18)(q21;q21)

We previously reported that activation of the B-cell-activating factor (BAFF) pathway upregulates nuclear factor-κB (NF-κB) and induces BCL3 and BCL10 nuclear translocation in Helicobacter pylori (HP)-independent gastric diffuse large B-cell lymphoma (DLBCL) tumours with evidence of mucosa-associated lymphoid tissue (MALT). However, the significance of BAFF expression in HP independence of gastric low-grade MALT lymphomas without t(11;18)(q21;q21) remains unexplored. Sixty-four patients who underwent successful HP eradication for localized HP-positive gastric MALT lymphomas without t(11;18)(q21;q21) were studied. BAFF expression was significantly higher in the HP-independent group than in the HP-dependent group [22/26 (84.6%) versus 8/38 (21.1%); p < 0.001]. Similarly, BAFF receptor (BAFF-R) expression (p = 0.004) and nuclear BCL3 (p = 0.004), BCL10 (p < 0.001), NF-κB (p65) (p = 0.001) and NF-κB (p52) (p = 0.005) expression were closely correlated with the HP independence of these tumours. Moreover, BAFF overexpression was significantly associated with BAFF-R expression and nuclear BCL3, BCL10, NF-κB (p65) and NF-κB (p52) expression. These findings were further validated in an independent cohort, including 40 HP-dependent cases and 18 HP-independent cases of gastric MALT lymphoma without t(11;18)(q21;q21). The biological significance of BAFF signalling in t(11;18)(q21;q21)-negative lymphoma cells was further studied in two types of lymphoma B cell: OCI-Ly3 [non-germinal centre B-cell origin DLBCL without t(11;18)(q21;q21) cell line] and MA-1 [t(14;18)(q32;q21)/IGH-MALT1-positive DLBCL cell line]. In both cell lines, we found that BAFF activated the canonical NF-κB and AKT pathways, and induced the formation of BCL10-BCL3 complexes, which translocated to the nucleus. BCL10 and BCL3 nuclear translocation and NF-κB (p65) transactivation were inhibited by either LY294002 or by silencing BCL3 or BCL10 with small interfering RNA. BAFF also activated non-canonical NF-κB pathways (p52) through tumour necrosis factor receptor-associated factor 3 degradation, NF-κB-inducing kinase accumulation, inhibitor of κB kinase (IKK) α/β phosphorylation and NF-κB p100 processing in both cell lines. Our data indicate that the autocrine BAFF signal transduction pathway contributes to HP independence in gastric MALT lymphomas without the t(11;18)(q21;q21) translocation. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

CagA Phosphorylation in Helicobacter pylori-Infected B Cells Is Mediated by the Nonreceptor Tyrosine Kinases of the Src and Abl Families

CagA is one of the most important virulence factors of the human pathogen Helicobacter pylori. CagA expression can be associated with the induction of severe gastric disorders such as gastritis, ulceration, gastric cancer, or mucosa-associated lymphoid tissue (MALT) lymphoma. After translocation through a type IV secretion system into epithelial cells, CagA is tyrosine phosphorylated by kinases of the Src and Abl families, leading to drastic cell elongation and motility. While the functional role of CagA in epithelial cells is well investigated, knowledge about CagA phosphorylation and its associated signal transduction pathways in B cells is only marginal. Here, we established the B cell line MEC1 derived from a B cell chronic lymphocytic leukemia (B-CLL) patient as a new infection model to study the signal transduction in B cells controlled by H. pylori. We observed that CagA was rapidly injected, strongly tyrosine phosphorylated, and cleaved into a 100-kDa N-terminal and a 40-kDa C-terminal fragment. To identify upstream signal transduction pathways of CagA phosphorylation in MEC1 cells, pharmacological inhibitors were employed to specifically target Src and Abl kinases. We observed that CagA phosphorylation was strongly inhibited upon treatment with an Src inhibitor and slightly diminished when the Abl kinase inhibitor imatinib mesylate (Gleevec) was applied. The addition of dasatinib to block c-Abl and Src kinases led to a complete loss of CagA phosphorylation. In conclusion, these results demonstrate an important role for Src and Abl tyrosine kinases in CagA phosphorylation in B cells, which represent druggable targets in H. pylori-mediated gastric MALT lymphoma.

The spectrum of MALT lymphoma at different sites: biological and therapeutic relevance

Extranodal marginal zone (MZ) B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The best evidence of an etiopathogenetic link is provided by the association between Helicobacter pylori–positive gastritis and gastric MALT lymphoma. Indeed, successful eradication of this microorganism with antibiotics can be followed by gastric MALT lymphoma regression in most cases. Other microbial agents have been implicated in the pathogenesis of MZ lymphoma arising at different sites. Apart from gastric MALT lymphoma, antibiotic therapies have been adequately tested only in ocular adnexal MALT lymphomas where upfront doxycycline may be a reasonable and effective initial treatment of patients with Chlamydophila psittaci–positive lymphoma before considering more aggressive strategies. In all other instances, antibiotic treatment of nongastric lymphomas remains investigational. Indeed, there is no clear consensus for the treatment of patients with gastric MALT lymphoma requiring further treatment beyond H pylori eradication or with extensive disease. Both radiotherapy and systemic treatments with chemotherapy and anti-CD20 antibodies are efficacious and thus the experience of individual centers and each patient’s preferences in terms of adverse effects are important parameters in the decision process.

A Positive Prospective Trial of Antibiotic Therapy in Advanced Stage, Non-Bulky Indolent Lymphoma

BACKGROUND

We have prospectively studied a three month course of clarithromycin (substituted by Prevpac^®, lansoprazole/ amoxicillin/ clarithromycin, in the first two wks when stool H pylori+) for non-bulky, advanced stage indolent lymphoma. These patients are often candidates for expectant monitoring and it is during this period that a window of opportunity may exist to identify and treat associated infections.

METHODS

All previously untreated patients with a new diagnosis of indolent lymphoma (FL and non-FL) meeting GELF criteria were treated with 12 weeks of clarithromycin. There were 32 evaluable patients, 4 of whom had stool H pylori.

RESULTS

At one month post-antibiotic therapy, we have observed lymphoma responses in 7 of 32 patients (21.9%). Two additional patients had objective response during followup (28.1% overall response). The median treatment free survival for antibiotic responders is 69.9 months and for non-responders, 30.6 months (p = 0.019).

CONCLUSION

Three response patterns have been noted, perhaps suggestive of an immune-mediated response -- prompt PET negative; flair with delayed PET negative response; and gradual continuous improvement. This prospective study appears promising, may be a step toward developing a lymphoma prevention strategy by reducing "antigen drive," and deserves further clinical/biological study. http://clinicaltrials.gov/show/NCT00461084.

Patho-epigenetics of Infectious Diseases Caused by Intracellular Bacteria

In multicellular eukaryotes including plants, animals and humans, epigenetic reprogramming may play a role in the pathogenesis of a wide variety of diseases. Recent studies revealed that in addition to viruses, pathogenic bacteria are also capable to dysregulate the epigenetic machinery of their target cells. In this chapter we focus on epigenetic alterations induced by bacteria infecting humans. Most of them are obligate or facultative intracellular bacteria that produce either bacterial toxins and surface proteins targeting the host cell membrane, or synthesise effector proteins entering the host cell nucleus. These bacterial products typically elicit histone modifications, i.e. alter the "histone code". Bacterial pathogens are capable to induce alterations of host cell DNA methylation patterns, too. Such changes in the host cell epigenotype and gene expression pattern may hinder the antibacterial immune response and create favourable conditions for bacterial colonization, growth, or spread. Epigenetic dysregulation mediated by bacterial products may also facilitate the production of inflammatory cytokines and other inflammatory mediators affecting the epigenotype of their target cells. Such indirect epigenetic changes as well as direct interference with the epigenetic machinery of the host cells may contribute to the initiation and progression of malignant tumors associated with distinct bacterial infections.

Survival of patients with gastric lymphoma in Germany and in the United States

BACKGROUND AND AIM

This study aims to examine survival for gastric lymphomas and its main subtypes, mucosa-associated lymphoid tissue lymphoma (MALT), and diffuse large B-cell lymphoma (DLBCL), in Germany and in the United States.

METHODS

Data for patients diagnosed in 1997-2010 were used from 10 population-based German cancer registries and compared to the data from the US Surveillance, Epidemiology and End Results (SEER) 13 registries database. Patients age 15-74 diagnosed with gastric lymphomas were included in the analysis. Period analysis and modeled period analysis were used to estimate 5-year and 10-year relative survival (RS) in 2002-2010 and survival trends from 2002-2004 to 2008-2010.

RESULTS

Overall, the database included 1534 and 2688 patients diagnosed with gastric lymphoma in 1997-2010 in Germany and in the United States, respectively. Survival was substantially higher for MALT (5-year and 10-year RS: 89.0% and 80.9% in Germany, 93.8% and 86.8% in the United States) than for DLBCL (67.5% and 59.2% in Germany, and 65.3% and 54.7% in the United States) in 2002-2010. Survival was slightly higher among female patients and decreased by age for gastric lymphomas combined and its main subtypes. A slight, nonsignificant, increase in the 5-year RS for gastric lymphomas combined was observed in Germany and the United States, with increases in 5-year RS between 2002-2004 and 2008-2010 from 77.1% to 81.0% and from 77.3% to 82.0%, respectively. Five-year RS of MALT exceeded 90% in 2008-2010 in both countries.

CONCLUSIONS

Five-year RS of MALT meanwhile exceeds 90% in both Germany and the United States, but DLBCL has remained below 70% in both countries.

Emerging role of infectious etiologies in the pathogenesis of marginal zone B-cell lymphomas

Extranodal marginal zone B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The most frequently affected organ is the stomach, where MALT lymphoma is incontrovertibly associated with a chronic gastritis induced by a microbial pathogen, Helicobacter pylori. Gastric MALT lymphoma therefore represents a paradigm for evaluating inflammation-associated lymphomagenesis, which may lead to a deeper understanding of a possible etiologic association between other microorganisms and nongastric marginal zone lymphomas. Besides infectious etiology, chronic inflammation caused by autoimmune diseases, such as Sjögren syndrome or Hashimoto thyroiditis, can also carry a significant risk factor for the development of marginal zone lymphoma. In addition to the continuous antigenic drive, additional oncogenic events play a relevant role in lymphoma growth and progression to the point at which the lymphoproliferative process may eventually become independent of antigenic stimulation. Recent studies on MALT lymphomas have in fact demonstrated genetic alterations affecting the NF-κB) pathway, a major signaling pathway involved in many cancers. This review aims to present marginal zone lymphoma as an example of the close pathogenetic link between chronic inflammation and tumor development, with particular attention to the role of infectious agents and the integration of these observations into everyday clinical practice. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

Clinical aspects of malt lymphomas

Extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT) is an indolent lymphoma arising in extranodal sites. Several infectious agents and autoimmune disorders have been implicated in its pathogenesis. The stomach represents the most common and best-studied organ involved by MALT lymphoma and its development is strongly associated with Helicobacter pylori (Hp) infection. MALT lymphomas are characterized by an indolent clinical course and excellent survival in most cases, independently of the treatment delivered. Recent progress in the knowledge of the etiology and the cellular and molecular pathological events related to MALT lymphomas allowed us to improve our clinical understanding of this disease entity and to better define treatment strategies.

Helicobacter pylori eradication in gastric diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) of the stomach is a heterogenous disease. There are tumors without histological evidence of mucosa-associated lymphoid tissue (MALT) lymphoma, which are classified as pure or de novo DLBCL and those with evidence of MALT, which are classified as DLBCL (MALT). The association between Helicobacter pylori (H. pylori) and gastric MALT lymphoma and remission with H. pylori eradication was shown in the 1990s. In recent years, scientists from Taiwan and others have shown that high-grade gastric lymphomas may be dependent on H. pylori and eradication of this microorganism is effective in these cases. This entity is biologically distinct from H. pylori (-) cases and has a better clinical outcome. There are sufficient data about the complete remission in some of these cases with brief treatment with antibiotics. With this strategy, it is possible to save some of these cases from the harmful effects of standard chemotherapy. It is time to treat these cases with H. pylori eradication. However, strict histopathological follow-up is crucial and histopathological response must be evaluated according to the scoring system proposed by Groupe d’Etude des Lymphomes de l’Adulte. If there is no sufficient response, chemotherapy must be given immediately. These results suggest that H. pylori dependency and high-grade transformation in gastric MALT lymphomas are distinct events.

Helicobacter pylori-related diffuse large B-cell lymphoma of the stomach: a distinct entity with lower aggressiveness and higher chemosensitivity

We recently showed that Helicobacter pylori (HP)-positive gastric ‘pure' diffuse large B-cell lymphoma (DLBCL) may respond to HP eradication therapy. However, whether these HP-related ‘pure' DLBCL of the stomach may differ fundamentally from those unrelated to HP remains unclear. In this study, we compared the clinicopathologic features of these two groups of patients who had been uniformly treated by conventional chemotherapy. Forty-six patients were designated HP-positive and 49 were HP-negative by conventional criteria. HP-positive patients had a lower International Prognostic Index score (0–1, 65% vs 43%, P=0.029), a lower clinical stage (I-IIE1, 70% vs 39%, P=0.003), a better tumor response to chemotherapy (complete pathologic response, 76% vs 47%, P=0.004) and significantly superior 5-year event-free survival (EFS) (71.7% vs 31.8%, P<0.001) and overall survival (OS) (76.1% vs 39.8%, P<0.001). To draw a closer biologic link with HP, HP-positive tumors were further examined for CagA expression in lymphoma cells. Compared with CagA-negative cases (n=16), CagA-positive cases (n=27) were associated with high phosphorylated SHP-2 expression (P=0.016), and even better 5-year EFS (85.2% vs 46.3%, P=0.002) and OS (88.9% vs 52.9%, P=0.003). HP-related gastric ‘pure' DLBCL may be a distinct tumor entity, which is less aggressive, and responds better to conventional chemotherapy.