Regression of primary low-grade B-cell gastric lymphoma of mucosa-associated lymphoid tissue type after eradication of Helicobacter pylori

[Gastrointestinal mucosa-associated lymphoma]

Mucosa-associated lymphomas of the gastrointestinal tract are a heterogeneous group differing in pathogenesis, localization and therapeutic options. For all of them, differentiated treatment requires an exact determination of lymphoma stage. For gastric MALT lymphoma, the pathogenetic role of Helicobacter pylori infection has become evident in the last 30 years. These insights were consequently implemented into clinical practice. Nowadays, Helicobacter pylori eradication is the treatment of choice for gastric MALT lymphoma, leading to complete remission of the lymphoma in the majority of cases. In the absence of success, radiotherapy is available in localized stages I/II E with excellent results. Immuno-chemotherapy is the domain for advanced stages III/IV E, and surgery plays no role any more. The rare intestinal and colorectal MALT lymphomas require an individualized therapeutic approach.

The second Irish Helicobacter pylori Working Group consensus for the diagnosis and treatment of Helicobacter pylori infection in adult patients in Ireland

BACKGROUND

There has been an increase in resistance to many of the antimicrobials used to treat Helicobacter pylori (H. pylori) nationally and internationally. Primary clarithromycin resistance and dual clarithromycin and metronidazole resistance are high in Ireland. These trends call for an evaluation of best-practice management strategies.

OBJECTIVE

The objective of this study was to revise the recommendations for the management of H. pylori infection in adult patients in the Irish healthcare setting.

METHODS

The Irish H. pylori working group (IHPWG) was established in 2016 and reconvened in 2023 to evaluate the most up-to-date literature on H. pylori diagnosis, eradication rates and antimicrobial resistance. The 'GRADE' approach was then used to rate the quality of available evidence and grade the resulting recommendations.

RESULTS

The Irish H. pylori working group agreed on 14 consensus statements. Key recommendations include (1) routine antimicrobial susceptibility testing to guide therapy is no longer recommended other than for clarithromycin susceptibility testing for first-line treatment (statements 6 and 9), (2) clarithromycin triple therapy should only be prescribed as first-line therapy in cases where clarithromycin susceptibility has been confirmed (statement 9), (3) bismuth quadruple therapy (proton pump inhibitor, bismuth, metronidazole, tetracycline) is the recommended first-line therapy if clarithromycin resistance is unknown or confirmed (statement 10), (4) bismuth quadruple therapy with a proton pump inhibitor, levofloxacin and amoxicillin is the recommended second-line treatment (statement 11) and (5) rifabutin amoxicillin triple therapy is the recommend rescue therapy (statement 12).

CONCLUSION

These recommendations are intended to provide the most relevant current best-practice guidelines for the management of H. pylori infection in adults in Ireland.

Should All Patients With Stage IE Gastric Mucosa-Associated Lymphoid Tissue Lymphoma Receive Antibiotic Eradication Therapy for Helicobacter pylori?

PURPOSE

H. pylori eradication therapy (HPE) can lead to tumor regression in H. pylori-positive (HPP) gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, some patients do not have detectable H. pylori (HP) infection (H. pylori-negative [HPN]) and the guidelines differ in their initial approach to HPN patients. The National Comprehensive Cancer Network (NCCN) recommends proceeding to radiation therapy, whereas European Society for Medical Oncology suggests HPE for every patient, even those who are HPN. To address this issue, we evaluated the effectiveness of HPE in limited-stage gastric MALT lymphoma.

MATERIALS AND METHODS

We retrospectively reviewed patients newly diagnosed with stage IE gastric MALT lymphoma between January 2002 and December 2022. The primary outcome was the complete remission (CR) rate defined as no macroscopic findings of lymphoma and negative gastric biopsy at the follow-up gastric endoscopy.

RESULTS

Fifty-two patients were reviewed, and HP infection was detected in 19 (36.5%) patients-14 by immunostaining, three by serology, and one each by stool antigen and urea breath test. All 19 HPP and eight of the 33 HPN patients received HPE treatment. The CR rate was 63% (12/19) in HPP patients and 13% (1/8) in HPN patients (P = .033). After a median follow-up of 89.7 months, only two of the 12 HPP patients achieving CR have relapsed; the one HPN patient who received HPE remains in CR at 12+ months.

CONCLUSION

For limited-stage HPP gastric MALT lymphoma, HPE is an effective and durable first-line treatment and should be used. For HPN patients, the CR rate with HPE is very low in our experience and is thus in support of the NCCN guideline.

Antimicrobial-resistant Helicobacter pylori in Japan: Report of nationwide surveillance for 2018-2020

BACKGROUND

Antimicrobial therapy is necessary to eradicate Helicobacter pylori infection. The emergence of antimicrobial-resistant bacteria poses a threat to continued treatment with antimicrobial agents. For those who prescribe antimicrobial therapy, it is necessary to constantly monitor the emergence of antimicrobial-resistant bacteria.

METHOD

H. pylori clinical isolates were collected in Japan from August 2018 to December 2020 for antimicrobial susceptibility testing. The agar dilution method was used for the determination of the minimum inhibitory concentration (MIC) of clarithromycin (CLR), amoxicillin (AMX), metronidazole (MNZ), and sitafloxacin (STX).

RESULTS

MICs for 938 H. pylori isolates were examined. The primary resistance rates of H. pylori clinical isolates for CLR, AMX, MNZ, and STX in Japan were 35.5%, 2.7%, 4.2%, and 27.6%, respectively. The primary resistance rates for CLR, AMX, and MNZ were significantly higher than those of the 2002-2005 isolates. The resistance rate for CLR was significantly higher in females (males: 30.7%, females: 41.5%, p < 0.001) and higher in the ≤29 years age group (54.8%) than in the other age groups, although there were no significant differences (p = 0.104). The MNZ resistance rate was significantly higher in the ≤29 years age group than in the other age groups (p = 0.004). The resistance rate for STX increased with age, but a significant difference was only seen between the 30-49 years age group and the ≥70 years age group (p < 0.001), and the resistance rate was significantly higher in strains isolated in the Kyushu region than in the other regions (p < 0.001).

CONCLUSIONS

The primary resistance rates for CLR, AMX, and MNZ of H. pylori clinical isolates in Japan were higher than those of the 2002-2005 isolates. Continuous surveillance is needed to monitor the trends in antimicrobial-resistant H. pylori.

H pylori-Negative MALT-Associated Extranodal Marginal Zone Lymphoma: A Comprehensive Case Report and Literature Review

Extranodal marginal zone B-cell lymphoma (ENMZL) of mucosa-associated lymphoid tissue (MALT), a rare subtype of B-cell lymphoma, is typically associated with Helicobacter pylori (H pylori) infection, especially in gastric cases. However, this article presents 2 unique cases of H pylori-negative colonic ENMZL, challenging the conventional understanding of the disease. The first case involves an 80-year-old male diagnosed with Stage 1E ENMZL in the descending colon, and the second describes a 74-year-old male with sigmoid colon ENMZL. Both cases lacked H pylori infection, adding complexity to their management. Accompanying these case studies is a comprehensive literature review, delving into the epidemiology, pathology, clinical features, diagnosis, and treatment of H pylori-negative ENMZL, with a focus on gastrointestinal involvement. This review highlights the importance of considering H pylori-negative cases in ENMZL diagnosis and management, illustrating the need for further research and individualized treatment approaches in this uncommon lymphoma subtype.

The Microbiome in the Obesity-Breast Cancer Axis: Diagnostic and Therapeutic Potential

A growing body of evidence has demonstrated a relationship between the microbiome, adiposity, and cancer development. The microbiome is emerging as an important factor in metabolic disease and cancer pathogenesis. This review aimed to highlight the role of the microbiome in obesity and its association with cancer, with a particular focus on breast cancer. This review discusses how microbiota dysbiosis may contribute to obesity and obesity-related diseases, which are linked to breast cancer. It also explores the potential of the gut microbiome to influence systemic immunity, leading to carcinogenesis via the modulation of immune function. This review underscores the potential use of the microbiome profile as a diagnostic tool and treatment target, with strategies including probiotics, fecal microbiota transplantation, and dietary interventions. However, this emphasizes the need for more research to fully understand the complex relationship between the microbiome, metabolic disorders, and breast cancer. Future studies should focus on elucidating the mechanisms underlying the impact of the microbiome on breast cancer and exploring the potential of the microbiota profile as a biomarker and treatment target.

Multi-Scale Hybrid Vision Transformer for Learning Gastric Histology: AI-Based Decision Support System for Gastric Cancer Treatment

Gastric endoscopic screening is an effective way to decide appropriate gastric cancer treatment at an early stage, reducing gastric cancer-associated mortality rate. Although artificial intelligence has brought a great promise to assist pathologist to screen digitalized endoscopic biopsies, existing artificial intelligence systems are limited to be utilized in planning gastric cancer treatment. We propose a practical artificial intelligence-based decision support system that enables five subclassifications of gastric cancer pathology, which can be directly matched to general gastric cancer treatment guidance. The proposed framework is designed to efficiently differentiate multi-classes of gastric cancer through multiscale self-attention mechanism using 2-stage hybrid vision transformer networks, by mimicking the way how human pathologists understand histology. The proposed system demonstrates its reliable diagnostic performance by achieving class-average sensitivity of above 0.85 for multicentric cohort tests. Moreover, the proposed system demonstrates its great generalization capability on gastrointestinal track organ cancer by achieving the best class-average sensitivity among contemporary networks. Furthermore, in the observational study, artificial intelligence-assisted pathologists show significantly improved diagnostic sensitivity within saved screening time compared to human pathologists. Our results demonstrate that the proposed artificial intelligence system has a great potential for providing presumptive pathologic opinion and supporting decision of appropriate gastric cancer treatment in practical clinical settings.

Clinical Management of Patients with Gastric MALT Lymphoma: A Gastroenterologist's Point of View

Gastric mucosa-associated lymphoid tissue (MALT) lymphomas (GML) are non-Hodgkin lymphomas arising from the marginal zone of the lymphoid tissue of the stomach. They are usually induced by chronic infection with Helicobacter pylori (H. pylori); however, H. pylori-negative GML is of increasing incidence. The diagnosis of GML is based on histological examination of gastric biopsies, but the role of upper endoscopy is crucial since it is the first step in the diagnostic process and, with currently available novel endoscopic techniques, may even allow an in vivo diagnosis of GML per se. The treatment of GML, which is usually localized, always includes the eradication of H. pylori, which should be performed even in H. pylori-negative GML. In the case of GML persistence after eradication of the bacteria, low-dose radiotherapy may be proposed, while systemic treatments (immunochemotherapy) should be reserved for very rare disseminated cases. In GML patients, at diagnosis but even after complete remission, special attention must be paid to an increased risk of gastric adenocarcinoma, especially in the presence of associated gastric precancerous lesions (gastric atrophy and gastric intestinal metaplasia), which requires adequate endoscopic surveillance of these patients.

Clinical relevance of molecular aspects in extranodal marginal zone lymphoma: a critical appraisal

Extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) is among the more common types of lymphoma accounting for up to 8% of newly diagnosed lymphoma cases. As opposed to other B-cell lymphomas, however, no predominant genetic hallmark has been defined in MALT lymphoma, but different localizations appear to be affected by different, sometimes distinct changes. Nonetheless, a high proportion of these genetic changes reported in MALT lymphomas dysregulate the pathways leading to NF-kB activation. t(11;18)(q21;q21)/BIRC3::MALT1 appears to be MALT lymphoma specific and is found in 24% of gastric and 40% of pulmonary MALT lymphomas. The translocation is associated with more disseminated disease in gastric MALT lymphoma and is found in a large percentage of patients whose lymphoma is unresponsive to antibiotic eradication of Helicobacter pylori. In addition to t(11;18)(q21;q21), nuclear expression of BCL10 or NF-kB appears to be highly associated with lymphoma cell survival independence of H. pylori-mediated stimulations. Antibiotic eradication, however, is the recommended therapy of choice irrespective of genetic findings, and molecular analysis is not required before initiation of therapy. The influence of genetic translocations including t(11;18)(q21;q21) on systemic therapies, however, is less clearly defined. While small series have shown no influence on the outcome for treatment with the anti-CD20 antibody rituximab (R) or treatment with cladribine (2-CdA), conflicting data have been reported for alkylating agents, especially chlorambucil and the combination of R + chlorambucil. None of other genetic changes seen in MALT lymphoma to date has discernible value in routine clinical applications, but recent data suggest that changes in TNFAIP3(A20), KMTD2 and CARD11 might be associated with response to Bruton kinase inhibitors.

Infection with Neoehrlichia mikurensis promotes the development of malignant B-cell lymphomas

The tick-borne pathogen Neoehrlichia (N.) mikurensis is implicated in persistent infection of the vascular endothelium. B cells are crucial for the host defence to this infection. Chronic stimulation of B cells may result in B-cell transformation and lymphoma. Five patients with malignant B-cell lymphoma and concomitant N. mikurensis infection were investigated regarding clinical picture, lymphoma subtype, B-cell lymphoma immunophenotype and IGHV (variable region of the immunoglobulin heavy) gene repertoire. Three of the five patients improved markedly and ceased lymphoma treatment after doxycycline treatment to eliminate N. mikurensis. Sequencing the B-cell lymphoma IGHV genes revealed preferred usage of the IGHV1 (IGHV1-2, and -69) and IGHV3 (IGHV3-15, -21, -23) families. In conclusion, N. mikurensis infection may drive the development of malignant B-cell lymphomas. Eradication of the pathogen appears to induce remission with apparent curing of the lymphoma in some cases.

Synchronous gastric MALT lymphoma and gastric adenocarcinoma of fundic gland type arising from a hamartomatous inverted polyp in a Helicobacter pylori naive patient

We present a rare case that showed the coexistence of gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma in Helicobacter pylori-naive stomach. A 72-year-old man was followed up after surgery for epithelial carcinoma of the glottis at the Department of Otolaryngology. He underwent an upper gastrointestinal endoscopy for an abnormal PET-CT accumulation, which revealed gastric adenocarcinoma of fundic gland type in the gastric fundus and MALT lymphoma in the upper gastric body. Hence, we performed an endoscopic submucosal dissection for gastric cancer and diagnosed gastric adenocarcinoma of fundic gland type derived from a hamartomatous-inverted polyp. Subsequently, Gastric MALT lymphoma was treated with radiation therapy because the API2-MALT1 gene was positive and the Helicobacter pylori infection was negative. A complete response was observed. Even in Hp-naive stomachs, cases such as the present case are complicated by special types of gastric cancer and MALT lymphoma, and endoscopic examination should be performed with these diseases in mind.

Helicobacter pylori infection

Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated. The infection affects around half of the population in the world but prevalence varies according to location and sanitation standards. H. pylori has unique properties to colonize gastric epithelium in an acidic environment. The pathophysiology of H. pylori infection is dependent on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors, resulting in distinct gastritis phenotypes that determine possible progression to different gastroduodenal pathologies. The causative role of H. pylori infection in gastric cancer development presents the opportunity for preventive screen-and-treat strategies. Invasive, endoscopy-based and non-invasive methods, including breath, stool and serological tests, are used in the diagnosis of H. pylori infection. Their use depends on the specific individual patient history and local availability. H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship.

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.

Regression of Mucosa-Associated Lymphoid Tissue Lymphoma Arising From the Nonampullary Descending Part of the Duodenum by Treatment With Antibiotics in a Helicobacter pylori-Negative Patient

We report a 63-year-old male, Helicobacter pylori-negative patient with mucosa-associated lymphoid tissue (MALT) lymphoma of the second part of the duodenum that regressed after antibiotic treatment. Esophagogastroduodenoscopy (EGD) showed flat elevation with shallow depression on the contralateral side of the ampulla of Vater. The lesion was limited to the duodenal second part. The patient had a history of Helicobacter pylori positivity, with successful eradication at 41 years of age. Twelve months after vonoprazan (VPZ)-based antibiotic treatment, the duodenal lesion had obviously regressed, and the pathological diagnosis was complete histological response (ChR). This case suggests that certain bacteria may promote the development of duodenal MALT lymphoma.

Long-term clinical outcomes of gastric mucosa-associated lymphoid tissue lymphoma in real-world experience

This long-term, retrospective, single-center study evaluated real-world clinical outcomes of gastric mucosa-associated lymphoid tissue (MALT) lymphoma using different therapeutic modalities and analyzed factors affecting survival outcomes and long-term prognosis. We enrolled 203 patients with pathologically confirmed low-grade gastric MALT lymphoma and examined their treatment responses. Helicobacter pylori eradication was performed in all patients with H. pylori infection (HPI) and localized stage gastric MALT lymphoma. All patients underwent pre-treatment and physical evaluations, with complete blood count, biochemistry panel, and staging workup. Among 144 HPI-positive patients with stage I or II1-2 disease who underwent H. pylori eradication, 112 (77.8%) achieved complete remission (CR). All HPI-negative patients who received first-line radiotherapy achieved CR (100%), but only 22 of 27 first-line chemotherapy-treated patients achieved CR (81.5%). Lesions in the proximal upper-third or in multiple locations and an invasion depth to the submucosa or deeper were associated with poor response to eradication, and HPI negativity was significantly correlated with poor progression-free survival. HPI eradication treatment should be the first-line treatment for patients with localized stage HPI-positive gastric MALT lymphoma. The "watch-and-wait" strategy should be adopted for delayed responders. We suggest radiotherapy for patients with a localized HPI-negative status or when eradication has failed.

Increased IL-17A Serum Levels and Gastric Th17 Cells in Helicobacter pylori-Infected Patients with Gastric Premalignant Lesions

Background: Helicobacter pylori infection is characterized by an inflammatory infiltrate that might be an important antecedent of gastric cancer. The purpose of this study was to evaluate whether interleukin (IL)-17 inflammation is elicited by gastric T cells in Helicobacter pylori patients with gastric intestinal metaplasia and dysplasia (IM/DYS). We also investigated the serum IL-17A levels in Helicobacter pylori patients with gastric intestinal metaplasia and dysplasia, and patients with Helicobacter pylori non-atrophic gastritis (NAG). Methods: the IL-17 cytokine profile of gastric T cells was investigated in six patients with IM/DYS and Helicobacter pylori infection. Serum IL-17A levels were measured in 45 Helicobacter pylori-infected IM/DYS patients, 45 Helicobacter pylori-infected patients without IM/DYS and in 45 healthy controls (HC). Results: gastric T cells from all IM/DYS patients with Helicobacter pylori were able to proliferate in response to Helicobacter pylori and to produce IL-17A. The Luminex analysis revealed that IL-17A levels were significantly increased in Helicobacter pylori IM/DYS patients compared to healthy controls and to Helicobacter pylori gastritis patients without IM/DYS (452.34 ± 369.13 pg/mL, 246.82 ± 156.06 pg/mL, 169.26 ± 73.82 pg/mL, respectively; p < 0.01, p < 0.05). Conclusions: the results obtained indicate that Helicobacter pylori is able to drive gastric IL-17 inflammation in IM/DYS Helicobacter pylori-infected patients, and that IL-17A serum levels are significantly increased in Helicobacter pylori-infected patients with IM/DYS.

Linfoma MALT de glándula parótida. Descripción de un caso

Introducción y objetivo: Los linfomas de la glándula parótida son una entidad infrecuente. Presentamos un caso clínico de linfoma tipo MALT de parótida, describiendo sus métodos diagnósticos y de tratamiento más empleados. Descripción: Mujer de 69 años con tumoración asintomática en cola de parótida y visión de estructuras nodulares en imagen de TC y RM con PAAF negativa. Se realiza parotidectomía total hallando el diagnóstico de linfoma MALT de la zona marginal. Se completa tratamiento mediante esquema R-CHOP durante 4 meses, sin signos de recidiva al año. Discusión: El linfoma tipo MALT es un tipo de LNH relacionado principalmente con inflamación autoinmune crónica en el caso de aparición sobre glándulas salivales. Se presenta como una tumoración asintomática e inespecífica de crecimiento lento y se diagnostica mediante TC o RM en su mayoría de casos. El tratamiento se realiza mediante parotidectomía asociado a quimioterapia y/o radioterapia, con una tasa de supervivencia mayor al 80% en 5 años. Conclusiones: Los linfomas de glándulas salivales son poco habituales y ocasionalmente se diagnostican de manera inadecuada debido a su comportamiento benigno que mimetiza a tumores más familiares del área parotídea. Su sospecha y distinción son esenciales y no deben olvidarse en nuestro diagnóstico diferencial de masas parotídeas.

Defining the Role of the Gut Microbiome in the Pathogenesis and Treatment of Lymphoid Malignancies

The gut microbiome is increasingly being recognized as an important immunologic environment, with direct links to the host immune system. The scale of the gut microbiome's genomic repertoire extends the capacity of its host's genome by providing additional metabolic output, and the close communication between gut microbiota and mucosal immune cells provides a continued opportunity for immune education. The relationship between the gut microbiome and the host immune system has important implications for oncologic disease, including lymphoma, a malignancy derived from within the immune system itself. In this review, we explore past and recent discoveries describing the role that bacterial populations play in lymphomagenesis, diagnosis, and therapy. We highlight key relationships within the gut microbiome-immune-oncology axis that present exciting opportunities for directed interventions intended to shape the microbiome for therapeutic effect. We conclude with a limited summary of active clinical trials targeting the microbiome in hematologic malignancies, along with future directions on gut microbiome investigations within lymphoid malignancies.

Tissue-Specific microRNA Expression Profiling to Derive Novel Biomarkers for the Diagnosis and Subtyping of Small B-Cell Lymphomas

Accurate diagnosis of the most common histological subtypes of small B-cell lymphomas is challenging due to overlapping morphological features and limitations of ancillary testing, which involves a large number of immunostains and molecular investigations. In addition, a common diagnostic challenge is to distinguish reactive lymphoid hyperplasia that do not require additional stains from such lymphomas that need ancillary investigations. We investigated if tissue-specific microRNA (miRNA) expression may provide potential biomarkers to improve the pathology diagnostic workflow. This study seeks to distinguish reactive lymphoid proliferation (RL) from small B-cell lymphomas, and to further distinguish the four main subtypes of small B-cell lymphomas. Two datasets were included: a discovery cohort (n = 100) to screen for differentially expressed miRNAs and a validation cohort (n = 282) to develop classification models. The models were evaluated for accuracy in subtype prediction. MiRNA gene set enrichment was also performed to identify differentially regulated pathways. 306 miRNAs were detected and quantified, resulting in 90-miRNA classification models from which smaller panels of miRNAs biomarkers with good accuracy were derived. Bioinformatic analysis revealed the upregulation of known and other potentially relevant signaling pathways in such lymphomas. In conclusion, this study suggests that miRNA expression profiling may serve as a promising tool to aid the diagnosis of common lymphoid lesions.

Diagnosis and Treatment for Gastric Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma, which was first reported in 1984, shows an indolent clinical course. However, the detailed clinicopathological characteristics of gastric MALT lymphoma have not been fully elucidated. We performed a literature search concerning the clinical features and treatment for gastric MALT lymphoma using PubMED. MALT lymphomas develop in single or multiple extranodal organs, of which the stomach is one of the most frequent sites; gastric MALT lymphoma accounts for 7% to 9% of all B-cell lymphomas, and 40% to 50% of primary gastric lymphomas. The eradication of Helicobacter pylori (H. pylori) is the first-line treatment for patients with gastric MALT lymphoma, regardless of the clinical stage. Approximately 60-90% of cases with stage I/II₁ disease only achieve a complete histological response via H. pylori eradication. In patients who do not respond to H. pylori eradication therapy, second-line treatments such as watch-and-wait, radiotherapy, chemotherapy, rituximab immunotherapy, and/or a combination of these are recommended. Thus, H. pylori plays a causative role in the pathogenesis of gastric MALT lymphoma, and H. pylori eradication leads to complete histological remission in the majority of cases.

Intestinal Mucosa-Associated Lymphoid Tissue Lymphoma Transforming into Diffuse Large B-Cell Lymphoma in a Young Adult Patient with Neurofibromatosis Type 1: A Case Report

Background: Neurofibromatosis type 1 (NF1) is a hereditary cancer syndrome characterized by multiple café-au-lait macules on the skin. Lymphoproliferative malignancies associated with NF1 are limited, although the most common are brain tumors. Case presentation: A 22-year-old woman with NF1 was admitted due to abdominal pain and bloody diarrhea. Her laboratory data exhibited macrocytic anemia and elevated IgA levels. Image studies showed diffuse increased wall thickening in the transverse and descending colon without lymphadenopathy and hepatosplenomegaly. A colonoscopy revealed a hemorrhagic ulcerated mass. Pathological analysis of the tumor tissues confirmed IgA-expressing mucosa-associated lymphoid tissue (MALT) lymphoma with histological transformation. Moreover, whole-exome sequencing in tumor tissues and peripheral blood mononuclear cells identified a somatic frameshift mutation of the A20 gene, which represents the loss of function. The patient responded well to R-CHOP chemotherapy, but the disease relapsed after 1 year, resulting in a lethal outcome. Conclusions: MALT lymphoma in children and young adults is extremely rare and is possibly caused by acquired genetic changes. This case suggests a novel association between hereditary cancer syndrome and early-onset MALT lymphoma.

Immunohistochemistry for IRTA1 and MNDA helps differentiate gastric MALT lymphoma from chronic gastritis/reactive lymphocyte hyperplasia

It is difficult to histologically differentiate extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) from chronic gastritis (CG)/ reactive lymphoid hyperplasia (RLH). To determine whether immunohistochemistry for IRTA1 and MNDA can differentiate gastric MALT lymphoma from CG/RLH, we investigated 81 stomach biopsy specimens [Wotherspoon grade (WG) 1, 11 cases; WG 2, 9 cases; WG 3, 20 cases; WG 4, 31 cases; and WG 5, 10 cases]. According to a previously reported algorithm involving PCR for immunoglobulin heavy (IgH) chain locus rearrangement, all 81 cases were divided into three groups: CG/RLH (55 cases), MALT lymphoma (19 cases) groups, and IgH undetectable group (7 cases). We analyzed the CG/RLH and MALT lymphoma groups. The median percentage of IRTA1-positive cells was 0% (range 0%-90.6%) in the CG/RLH group and 43.5% (range 0%-97.6%) in the MALT lymphoma group (p < 0.0001). The median percentage of MNDA-positive cells was 32.4% (range 0%-97.6%) in the CG/RLH group and 55.1% (range 0%-97.6%) in the MALT lymphoma group (p = 0.0044). These results indicate that immunohistochemistry for IRTA1 and MNDA can help differentiate gastric MALT lymphoma from CG/RLH.

Synchronous early gastric and intestinal mucosa-associated lymphoid tissue lymphoma in a Helicobacter pylori-negative patient: A case report

BACKGROUND

Mucosa-associated lymphoid tissue (MALT) lymphoma occurs largely in the digestive tract, with the stomach being the most commonly affected organ, followed by the small intestine, large intestine, and esophagus. It is rarely found in both the stomach and colon. Helicobacter pylori (H. pylori) infection is strongly associated with gastric MALT lymphoma, although there is a small number of H. pylori-negative gastric MALT lymphomas. Diagnosis of MALT lymphoma is challenging because of nonspecific symptoms and diverse presentations of endoscopic findings.

CASE SUMMARY

We report a case of an asymptomatic patient who during screening endoscopy and was found to have stromal tumor-like submucosal uplift lesions in the stomach body and polypoid lesions in the rectum. After endoscopic resection, the patient was diagnosed with multiple early simultaneous gastrointestinal MALT lymphomas.

CONCLUSION

This study may help improve our understanding of MALT lymphomas and multifocal lesions treated using early endoscopy.

A Bioluminescence-Based Drug Screen Identifies Activities of Fexinidazole and Its Metabolites against Helicobacter pylori

Helicobacter pylori is responsible for a wide range of gastric diseases, including gastric cancer and gastritis. With half of the world’s population infected by H. pylori and the current standard of care associated with suboptimal outcomes, a search for more effective drugs is critical. To facilitate drug screening for H. pylori, we developed a microtiter plate-based compound screening method that is faster and can screen multiple compounds. We identified activities of fexinidazole and its sulfoxide and sulfone metabolites against H. pylori. Both fexinidazole and its metabolites exhibited equipotency against SS1, 60190, and G27 strains, which were about 3–6-fold more potent than the currently used metronidazole. We also determined the minimal inhibitory concentration (MIC) of metronidazole, fexinidazole, and its metabolites against these strains by a traditional agar plate-based method. While MIC values of fexinidazole and metronidazole were similar against all the strains, both sulfoxide and sulfone showed lower MIC values than metronidazole against SS1 and 60190. Given the recent FDA approval of fexinidazole, our data on the in vitro antibacterial activities of fexinidazole and its metabolites support further evaluation of this drug with the goal of producing an alternative nitro-based antimicrobial with good safety profiles for the treatment of H. pylori infection.

High endothelial venules as potential gateways for therapeutics

High endothelial venules (HEVs) are specialized blood vessels that support the migration of lymphocytes from the bloodstream into lymph nodes (LNs). They are also formed ectopically in mammalian organs affected by chronic inflammation and cancer. The recent arrival of immunotherapy at the forefront of many cancer treatment regimens could boost a crucial role for HEVs as gateways for the treatment of cancer. In this review, we describe the microanatomical and biochemical characteristics of HEVs, mechanisms of formation of newly made HEVs, immunotherapies potentially dependent on HEV-mediated T cell homing to tumors, and finally, how HEV-targeted therapies might be used as a complementary approach to potentially shape the therapeutic landscape for the treatment of cancer and immune-mediated diseases.

B‐cell receptors of EBV‐negative Burkitt lymphoma bind modified isoforms of autoantigens

Burkitt lymphoma (BL) represents the most aggressive B‐cell‐lymphoma. Beside the hallmark of IG‐MYC‐translocation, surface B‐cell receptor (BCR) is expressed, and mutations in the BCR pathway are frequent. Coincidental infections in endemic BL, and specific extra‐nodal sites suggest antigenic triggers. To explore this hypothesis, BCRs of BL cell lines and cases were screened for reactivities against a panel of bacterial lysates, lysates of Plasmodium falciparum, a custom‐made virome array and against self‐antigens, including post‐translationally modified antigens.

An atypically modified, SUMOylated isoform of Bystin, that is, SUMO1‐BYSL was identified as the antigen of the BCR of cell line CA46. SUMO1‐BYSL was exclusively expressed in CA46 cells with K139 as site of the SUMOylation. Secondly, an atypically acetylated isoform of HSP40 was identified as the antigen of the BCR of cell line BL41. K104 and K179 were the sites of immunogenic acetylation, and the acetylated HSP40 isoform was solely present in BL41 cells. Functionally, addition of SUMO1‐BYSL and acetylated HSP40 induced BCR pathway activation in CA46 and BL41 cells, respectively. Accordingly, SUMO1‐BYSL‐ETA’ immunotoxin, produced by a two‐step intein‐based conjugation, led to the specific killing of CA46 cells. Autoantibodies directed against SUMO1‐BYSL were found in 3 of 14 (21.4%), and autoantibodies against acetylated HSP40 in 1/14(7.1%) patients with sporadic Burkitt‐lymphoma. No reactivities against antigens of the infectious agent spectrum could be observed.

These results indicate a pathogenic role of autoreactivity evoked by immunogenic post‐translational modifications in a subgroup of sporadic BL including two EBV‐negative BL cell lines.

Gastric Helicobacter species associated with dogs, cats and pigs: significance for public and animal health

This article focuses on the pathogenic significance of Helicobacter species naturally colonizing the stomach of dogs, cats and pigs. These gastric "non-Helicobacter (H.) pylori Helicobacter species" (NHPH) are less well-known than the human adapted H. pylori. Helicobacter suis has been associated with gastritis and decreased daily weight gain in pigs. Several studies also attribute a role to this pathogen in the development of hyperkeratosis and ulceration of the non-glandular stratified squamous epithelium of the pars oesophagea of the porcine stomach. The stomach of dogs and cats can be colonized by several Helicobacter species but their pathogenic significance for these animals is probably low. Helicobacter suis as well as several canine and feline gastric Helicobacter species may also infect humans, resulting in gastritis, peptic and duodenal ulcers, and low-grade mucosa-associated lymphoid tissue lymphoma. These agents may be transmitted to humans most likely through direct or indirect contact with dogs, cats and pigs. Additional possible transmission routes include consumption of water and, for H. suis, also consumption of contaminated pork. It has been described that standard H. pylori eradication therapy is usually also effective to eradicate the NHPH in human patients, although acquired antimicrobial resistance may occasionally occur and porcine H. suis strains are intrinsically less susceptible to aminopenicillins than non-human primate H. suis strains and other gastric Helicobacter species. Virulence factors of H. suis and the canine and feline gastric Helicobacter species include urease activity, motility, chemotaxis, adhesins and gamma-glutamyl transpeptidase. These NHPH, however, lack orthologs of cytotoxin-associated gene pathogenicity island and vacuolating cytotoxin A, which are major virulence factors in H. pylori. It can be concluded that besides H. pylori, gastric Helicobacter species associated with dogs, cats and pigs are also clinically relevant in humans. Although recent research has provided better insights regarding pathogenic mechanisms and treatment strategies, a lot remains to be investigated, including true prevalence rates, exact modes of transmission and molecular pathways underlying disease development and progression.

Laparoscopic distal gastrectomy for synchronous adenocarcinoma, diffuse large B cell lymphoma and gastrointestinal stromal tumor in the stomach: a case report

BACKGROUND

Synchronous lymphoma and adenocarcinoma are occasionally detected in the stomach. Gastrointestinal stromal tumor (GIST) and adenocarcinoma are sometimes seen simultaneously in the stomach. However, we rarely observe synchronous adenocarcinoma, lymphoma, and GIST in the stomach, and there are few reports on cases with these three lesions.

CASE PRESENTATION

This is a case report of a 71-year-old man who had a laparoscopic distal gastrectomy and lymphadenectomy for three gastric tumors. Preoperative diagnoses were early adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma in the stomach, but final diagnosis was synchronous adenocarcinoma, diffuse large B cell lymphoma (DLBCL), and GIST. Helicobacter pylori (H. pylori) is highly involved in the development of DLBCL and MALT lymphoma in the stomach. Gastric adenocarcinoma is partially involved in chronic gastritis with atrophy and intestinal metaplasia caused by H. pylori infection. Indeed, a rapid urease test was found positive in this case. Therefore, we prescribed medicine to eliminate H. pylori after gastrectomy.

CONCLUSION

This is the first case report where a patient underwent minimally invasive laparoscopic gastrectomy for synchronous adenocarcinoma, DLBCL and GIST in the stomach, although one patient who underwent open gastrectomy for synchronous adenocarcinoma, MALT lymphoma and GIST was previously reported.

A B-cell or a key player? The different roles of B-cells and antibodies in melanoma

The B‐cell system plays an important role in the melanoma immune response; however, consensus has yet to be reached in many facets. Here, we comprehensively review human studies only, due to fundamental differences in the humoral response with animal models. Tumour‐infiltrating B‐cells are associated with contradictory prognostic values, reflecting a lack of agreement between studies on cell subset classification and differences in the markers used, particularly the common use of a single marker not differentiating multiple subsets. Tertiary lymphoid structures (TLS) organise T‐cells and B‐cells within tumours to generate a local anti‐tumour response and TLS presence associates with improved survival in response to immune checkpoint blockade, in late‐stage disease. Autoantibody production is increased in melanoma patients and has been proposed as biomarkers for diagnosis, prognosis and treatment/toxicity response; however, no consistent targets are yet identified. The function of antibodies in an anti‐tumour response is determined by its isotype and subclass; IgG₄ is immune‐suppressive and robustly correlate with poor patient survival in melanoma. We conclude that the current B‐cell literature needs careful interpretation based on the methods used and that we need a consensus of markers to define B‐cells and associated lymphoid organs. Furthermore, future studies need to not only examine antibody targets, but also isotypes when considering functional roles.

Host-microbe interactions and outcomes in multiple myeloma and hematopoietic stem cell transplantation

Microbiota are essential to normal immune development and there is growing recognition of its importance to human health and disease and deepening understanding of the complexity of host-microbe interactions in the human gut and other tissues. Commensal microbes not only can influence host immunity locally through impacts of bioactive microbial metabolites and direct interactions with epithelial cells and innate immune receptors but also can exert systemic immunomodulatory effects via impacts on host immune cells capable of trafficking beyond the gut. Emerging data suggest microbiota influence the development of multiple myeloma (MM), a malignancy of the immune system derived from immunoglobulin-producing bone marrow plasma cells, through the promotion of inflammation. Superior treatment outcomes for MM correlate with a higher abundance of commensal microbiota capable of influencing inflammatory responses through the production of butyrate. In patients with hematologic malignancies, higher levels of diversity of the gut microbiota correlate with superior outcomes after hematopoietic stem cell transplantation. Correlative data support the impact of commensal microbiota on survival, risk of infection, disease relapse, and graft-versus-host disease (GVHD) after transplant. In this review, we will discuss the current understanding of the role of host-microbe interactions and the inflammatory tumor microenvironment of multiple myeloma, discuss data describing the key role of microbiota in hematopoietic stem cell transplantation for treatment of hematologic malignancies, and highlight several possible concepts for interventions directed at the gut microbiota to influence treatment outcomes.

Extranodal Marginal Zone Lymphoma: Pathogenesis, Diagnosis and Treatment

Simple Summary

Extranodal marginal zone lymphoma (EMZL) is an indolent lymphoproliferative disease morphologically composed of small heterogeneous B lymphocytes. It generally occurs with a localized stage and can arise in various organs, the most frequent being the stomach, lung, and ocular adnexa. Depending on the presentation and the possible association with infectious agents, different therapeutic approaches are to be undertaken. The purpose of this review is to describe the biology underlying this pathology, the diagnostic, and therapeutic approach.

Abstract

Extranodal Marginal Zone Lymphoma (EMZL lymphoma) is an indolent B-cell lymphoma with a median age at diagnosis of about 60 years. It accounts for 7–8% of all B-cell lymphomas. It can occur in various extranodal sites, including stomach, lung, ocular adnexa, and skin; furthermore, the disseminated disease can be found in 25–50% of cases. Several infectious agents, such as Helicobacter pylori (H. Pylori) in the case of gastric Mucosa Associated Lymphoid Tissue (MALT) Lymphoma, can drive the pathogenesis of this cancer, through the autoantigenic stimulation of T cells, but there may also be other factors participating such autoimmune diseases. Initial staging should include total body computed tomography, bone marrow aspirate, and endoscopic investigation if indicated. Fluorescence in situ hybridization (FISH), should be performed to detect the presence of specific chromosomal translocations involving the MALT1 and BCL10 genes, which leads to the activation of the NF-κB signaling pathway. Depending on the location and dissemination of the disease, different therapeutic choices may include targeted therapy against the etiopathogenetic agent, radiotherapy, immunochemotherapy, and biological drugs. The purpose of this review is to illustrate the complex biology and the diagnosis of this disease and to better define new treatment strategies.

Roles of Microbiota in Cancer: From Tumor Development to Treatment

Cancer as a second leading cause of death arises from multifactorial pathology. The association of microbiota and their products with various pathologic conditions including cancer is receiving significant attention over the past few years. Mounting evidence showed that human microbiota is an emerging target in tumor onset, progression, prevention, and even diagnosis. Accordingly, modulating this composition might influence the response to tumor therapy and therapeutic resistance as well. Through this review, one could conceive of complex interaction between the microbiome and cancer in either positive or negative manner by which may hold potential for finding novel preventive and therapeutic strategies against cancer.

Two subsets of human marginal zone B cells resolved by global analysis of lymphoid tissues and blood

B cells generate antibodies that are essential for immune protection, but their subgroups are poorly defined. Here, we perform undirected deep profiling of B cells in matched human lymphoid tissues from deceased transplant organ donors and blood. In addition to identifying unanticipated features of tissue-based B cell differentiation, we resolve two subsets of marginal zone B (MZB) cells differing in cell surface and transcriptomic profiles, clonal relationships to other subsets, enrichment of genes in the NOTCH pathway, distribution bias within splenic marginal zone microenvironment, and immunoglobulin repertoire diversity and hypermutation frequency. Each subset is present in spleen, gut-associated lymphoid tissue, mesenteric lymph nodes, and blood. MZB cells and the lineage from which they are derived are depleted in lupus nephritis. Here, we show that this depletion is of only one MZB subset. The other remains unchanged as a proportion of total B cells compared with health. Thus, it is important to factor MZB cell heterogeneity into studies of human B cell responses and pathology.

Development of Organ-Preserving Radiation Therapy in Gastric Marginal Zone Lymphoma

Simple Summary

Gastric marginal zone lymphoma of the stomach is a rare cancer type primarily treated with oral proton pump inhibitors. If the disease does not respond to this, radiation is the treatment of choice. This review presents the development of radiation therapy over the last decades. Earlier, the stomach was surgically removed and irradiation was performed using large-field techniques and high doses of radiation. Currently, the standard treatment is the use of small-volume radiation therapy (with few side effects) with the preservation of the stomach, which provides excellent outcomes. In addition, this paper provides an outlook on current studies and possible future developments.

Abstract

Gastric marginal zone lymphoma (gMZL) of mucosa-associated lymphoid tissue (MALT) may persist even after H. pylori eradication, or it can be primarily Helicobacter pylori (H. pylori) independent. For patients without the successful eradication of lymphoma, or with progressive disease, treatment options have historically included partial or total gastrectomy. Presently, in these instances, curative radiation therapy (RT) is the current standard of care. This review emphasizes the historically changing role of radiation therapy in gMZL, progressing from large-volume RT without surgery, to localized RT, on its own, as a curative organ-preserving treatment. This overview shows the substantial progress in radiation therapy during the recent two to three decades, from high-dose, large-field techniques to low-dose, localized target volumes based on advanced imaging, three-dimensional treatment planning, and advanced treatment delivery techniques. RT has evolved from very large extended field techniques (EF) with prophylactic treatment of the whole abdomen and the supradiaphragmatic lymph nodes, applying doses between 30 and 50 Gy, to involved-field RT (IF), to the current internationally recommended involved site radiation therapy (ISRT) with a radiation dose of 24–30 Gy in gMZL. Stage-adapted RT is a highly effective and safe treatment with excellent overall survival rates and very rare acute or late treatment-related toxicities, as shown not only in retrospective studies, but also in large prospective multicenter studies, such as those conducted by the German Study Group on Gastrointestinal Lymphoma (DSGL). Further de-escalation of the radiation treatments with low-dose 20 Gy, as well as ultra-low-dose 4 Gy radiation therapy, is under investigation within ongoing prospective clinical trials of the International Lymphoma Radiation Oncology Group (ILROG) and of the German Lymphoma Alliance (GLA).

The Role of Gut Microbiota in Gastrointestinal Tract Cancers

Disturbances in gastrointestinal (GI) microbiota could play a significant role in the development of GI cancers, but the underlying mechanisms remain largely unclear. While some bacteria seem to facilitate carcinogenesis, others appear to be protective. So far only one bacterium (Helicobacter pylori) has been classified by the International Agency for Cancer Research as carcinogenic in humans but many other are the subject of intense research. Most studies on the role of microbiota in GI tract oncogenesis focus on pancreatic and colorectal cancers with the following three species: Helicobacter pylori, Escherichia coli, and Porphyromonas gingivalis as likely causative factors. This review summarizes the role of bacteria in GI tract oncogenesis.

Histologic detection of Helicobacter pylori by the immunohistochemical method using anti-Helicobacter pylori polyclonal antibody: A cross-sectional study of patients with gastric pathologies at the Muhimbili National Hospital in Dar-es-salaam, Tanzania

BACKGROUND AND STUDY AIM

Immunohistochemistry is one of the superior methods and is regarded as the gold standard for the detection of Helicobacter pylori. We aimed to detect the presence of Helicobacter pylori in gastric biopsies among patients at the Muhimbili National Hospital from January 2012 to December 2016. Also, we determined the predictors of Helicobacter pylori infection.

PATIENTS AND METHODS

Retrospectively, we retrieved the tissue blocks of gastric biopsies at the Central Pathology Laboratory of the patients with different gastric pathologies at the Muhimbili National Hospital from January 2012 to December 2016. Helicobacter pylori were detected using anti-Helicobacter pylori polyclonal antibodies. Binary logistic regression analysis was done to determine the predictors of Helicobacter pylori infection. A two-tailed p < 0.05 was considered significant.

RESULTS

The prevalence of detection of Helicobacter pylori was 37.1% (63/170) using immunohistochemistry compared to 32.4% (55/170) using histology. Peptic ulcer disease, the absence of gastric cancer, and chronic gastritis were the predictors of Helicobacter pylori infection in our study (AOR = 0.2, 95% CI = 0.06-0.70, p = 0.011, AOR = 3.23, 95% CI = 1.02-10.29, p = 0.047, AOR = 0.32, 95% CI = 0.12-0.87, p = 0.025, respectively).

CONCLUSION

In this study, Helicobacter pylori infection was associated with the presence of peptic ulcer disease, chronic gastritis, and the absence of gastric cancer. The rate of detection of Helicobacter pylori infection was higher in tissue blocks of elderly patients than in those of young patients. Also, gastric cancer was more prevalent in old female patients.

Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma in the Gastrointestinal Tract in the Modern Era

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) typically arises from sites such as the stomach, where there is no organized lymphoid tissue. Close associations between Helicobacter pylori and gastric MALT lymphoma or Campylobacter jejuni and immunoproliferative small intestinal disease (IPSID) have been established. A subset of tumors is associated with chromosomal rearrangement and/or genetic alterations. This disease often presents as localized disease, requiring diverse treatment approaches, from antibiotic therapy to radiotherapy and immunochemotherapy. Eradication therapy for H. pylori effectively cures gastric MALT lymphoma in most patients. However, treatment strategies for H. pylori-negative gastric MALT lymphoma are still challenging. In addition, the effectiveness of antibiotic therapy has been controversial in intestinal MALT lymphoma, except for IPSID. Endoscopic treatment has been noted to usually achieve complete remission in endoscopically resectable colorectal MALT lymphoma with localized disease. MALT lymphoma has been excluded from post-transplant lymphoproliferative disorders with the exception of Epstein–Barr virus (EBV)-positive marginal zone lymphoma (MZL). We also describe the expanding spectrum of EBV-negative MZL and a close association of the disease with the gastrointestinal tract.

Diagnosis of MALT Lymphoma from Surveillance Endoscopy of a Patient with a CDH1 Gene Germline Mutation

Carriers of the mutated CDH1 gene have an increased risk of developing early-onset signet-ring cell (diffuse) gastric cancer. We present a case of a young patient with a confirmed mutation of the CDH1 gene, who was diagnosed with a gastric marginal zone B-cell lymphoma (MZL) of mucosa-associated lymphoid tissue (MALT lymphoma) from surveillance endoscopy. He underwent Helicobacter pylori eradication treatment and was subsequently submitted to a total prophylactic gastrectomy. The surgical specimen only revealed foci of signet-ring cell carcinoma (SRCC) in situ without lymphoma signs. We highlight here the occurrence of other pathology in high-risk patients as well as its possible influence on the decision to perform gastrectomy.

The role of B cells in the development, progression, and treatment of lymphomas and solid tumors

B cells are integral components of the mammalian immune response as they have the ability to generate antibodies against an almost infinite array of antigens. Over the past several decades, significant scientific progress has been made in understanding that this enormous B cell diversity contributes to pathogen clearance. However, our understanding of the humoral response to solid tumors and to tumor-specific antigens is unclear. In this review, we first discuss how B cells interact with other cells in the tumor microenvironment and influence the development and progression of various solid tumors. The ability of B lymphocytes to generate antibodies against a diverse repertoire of antigens and subsequently tailor the humoral immune response to specific pathogens relies on their ability to undergo genomic alterations during their development and differentiation. We will discuss key transforming events that lead to the development of B cell lymphomas. Overall, this review provides a foundation for innovative therapeutic interventions for both lymphoma and solid tumor malignancies.

Helicobacter pylori-negative extra-nodal marginal zone B-cell lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) type following Roux-en-Y Gastric Bypass (RYGB)

Gastric MALT lymphoma is a common type of non-Hodgkin's lymphoma that has the potential for cure in patients found to have concomitant Helicobacter pylori (H. pylori) infection. This case report explores the evaluation, diagnosis, and treatment of H. pylori-negative MALT lymphoma in a patient with a history of a RYGB.

[Rectal Mucosa-associated Lymphoid Tissue Lymphoma Treated with Endoscopic Resection]

A primary extranodal B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) is a distinct clinical-pathological entity that develops in diverse anatomic locations. However, colorectal involvement is rare. The authors encountered a case of a MALT lymphoma of the rectum in a 69-year-old woman who complained of up to 3 kg weight loss during 3 months. A colonoscopy demonstrated a 1.0×1.0 cm sized subepithelial tumor (SET) at the lower rectum. The patient underwent an endoscopic mucosal resection with ligation for the SET. Pathological analysis revealed marked small to medium-sized lymphocytic infiltration. Immunohistochemistry revealed neoplastic cells positive for CD20 and bcl-2. A polymerase chain reaction detected immunoglobulin H gene rearrangement. Finally, rectal MALT lymphoma was diagnosed. Computed tomography and positron emission tomography scans showed that there was no lymph node metastasis or other organ involvement. A bone marrow biopsy was found to be negative for any neoplastic process. Therefore, the Ann Arbor stage was IeB. Helicobacter pylori (H. pylori) was not detected in the gastric biopsy specimens. Thus far, she has had no relapse since the endoscopic resection. The incidence of rectal MALT is very rare, and treatment is unclear. This paper reports a case of rectal MALT lymphoma treated successfully with only an endoscopic resection.

[Gastric MALT lymphoma - from pathogenetic insights to consequent deescalation of therapy]

Gastric MALT- (mucosa-associated-lymphoid-tissue) lymphoma represents the most frequent gastrointestinal lymphoma. For decades, surgery and later on radiation and chemotherapy were regarded as established therapy. Some 30 years ago, the pathogenetic role of Helicobacter pylori infection for the development of gastric MALT-lymphoma became evident. During the following years, the pathogenetic insights were consequently implemented into clinical medicine. This lead to a radical change of the therapeutic approach to these lymphoma. Nowadays, Helicobacter pylori eradication is the internationally established therapy of first choice. It is followed by lymphoma regression in most cases. The long-term prognosis of patients after exclusive eradication therapy is excellent, even if endoscopic and/or histological residuals persist and a watch-and-wait strategy is favored.The pathogenetic insights und their clinical application implicated a consequent deescalation of therapy of gastric MALT-lymphoma. This review summarizes the single steps of this development and gives a recommendation for the actual management of patients with gastric MALT lymphoma.

Long-Term Clinical Outcomes of Gastric MALT Lymphoma: A Nationwide Multicenter Study in Korea

Background

Treatment recommendations for gastric mucosa-associated lymphoid tissue (MALT) lymphoma are based on case series and expert opinions. Only a few previous studies have focused on the long-term outcomes of gastric MALT lymphoma, especially according to stage.

Methods

Patients diagnosed with gastric MALT lymphoma from January 2000 to December 2018 at nine university hospitals in Korea were included. Clinical data of medical history, endoscopic features, histological diagnosis, results of Helicobacter pylori (H. pylori) testing, stage, treatment conditions, and outcomes were collected.

Results

A total of 1,163 patients was enrolled, and 97.6% (n=1,038) of patients were diagnosed as stage IE. 10-year overall survival (OS) for the entire population was 99.1% and was better for patients in stage IE compared with patients in stage III/IV (p=0.002). The 10-year OS for H. pylori-positive patients was better than that of H. pylori-negative patients (p=0.022). Multivariate analyses revealed initial stage III/IV as a prognostic factor associated with over-all survival.

Conclusion

The majority of gastric MALT lymphoma patients are diagnosed at an early localized stage in Korea. The overall survival rate of gastric MALT lymphoma is excellent and is associated with the initial stage of the disease.

What you always wanted to know about gastric MALT-lymphoma: a focus on recent developments

The stomach is the most common site of origin for extranodal lymphomas, with extranodal marginal zone B-cell of the mucosa associated lymphoid tissue (MALT-lymphoma) being the predominant subtype. MALT-lymphoma develops in mucosa associated lymphoid structures acquired by infection or chronic antigenic stimuli and may therefore arise in almost any organ of the human body. In spite of histopathologic similarities between various organs upon first glance, recent findings suggest pronounced differences between different sites, with a variety of features specific to gastric MALT-lymphoma. The objective of this review is to sum up the current knowledge on pathogenesis, molecular pathology, clinical presentation and therapeutic approaches to gastric MALT-lymphoma with in-depth discussion of recent developments.

The Helicobacter pylori CagY Protein Drives Gastric Th1 and Th17 Inflammation and B Cell Proliferation in Gastric MALT Lymphoma

Background: the neoplastic B cells of the Helicobacter pylori-related low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma proliferate in response to H. pylori, however, the nature of the H. pylori antigen responsible for proliferation is still unknown. The purpose of the study was to dissect whether CagY might be the H. pylori antigen able to drive B cell proliferation. Methods: the B cells and the clonal progeny of T cells from the gastric mucosa of five patients with MALT lymphoma were compared with those of T cell clones obtained from five H. pylori–infected patients with chronic gastritis. The T cell clones were assessed for their specificity to H. pylori CagY, cytokine profile and helper function for B cell proliferation. Results: 22 of 158 CD4⁺ (13.9%) gastric clones from MALT lymphoma and three of 179 CD4⁺ (1.7%) clones from chronic gastritis recognized CagY. CagY predominantly drives Interferon-gamma (IFN-γ) and Interleukin-17 (IL-17) secretion by gastric CD4⁺ T cells from H. pylori-infected patients with low-grade gastric MALT lymphoma. All MALT lymphoma-derived clones dose dependently increased their B cell help, whereas clones from chronic gastritis lost helper activity at T-to-B-cell ratios greater than 1. Conclusion: the results obtained indicate that CagY drives both B cell proliferation and T cell activation in gastric MALT lymphomas.

Gastrointestinal lymphoproliferative lesions: a practical diagnostic approach

The gastrointestinal tract (GI) is the primary site of lymphoproliferative lesions, spanning from reactive lymphoid hyperplasia to overt lymphoma. The diagnosis of these diseases is challenging and an integrated approach based on clinical, morphological, immunohistochemical and molecular data is needed. To reach to confident conclusions, a stepwise approach is highly recommended. Histological evaluation should first assess the benign versus neoplastic nature of a given lymphoid infiltrate. Morphological and phenotypic analyses should then be applied to get to a definite diagnosis.

This review addresses the key histological features and diagnostic workup of the most common GI non-Hodgkin lymphomas (NHLs). Differential diagnoses and possible pitfalls are discussed by considering distinct groups of lesions (i.e. small to medium B-cell NHLs; medium to large B-cell NHLs; T-cell NHLs; and mimickers of Hodgkin lymphoma). The key clinical and epidemiological features of each entity are also described.

Helicobacter pylori eradication: Exploring its impacts on the gastric mucosa

Helicobacter pylori (H. pylori) infects approximately 50% of all humans globally. Persistent H. pylori infection causes multiple gastric and extragastric diseases, indicating the importance of early diagnosis and timely treatment. H. pylori eradication produces dramatic changes in the gastric mucosa, resulting in restored function. Consequently, to better understand the importance of H. pylori eradication and clarify the subsequent recovery of gastric mucosal functions after eradication, we summarize histological, endoscopic, and gastric microbiota changes to assess the therapeutic effects on the gastric mucosa.

Helicobacters and cancer, not only gastric cancer?

The Helicobacter genus actually comprises 46 validly published species divided into two main clades: gastric and enterohepatic Helicobacters. These bacteria colonize alternative sites of the digestive system in animals and humans, and contribute to inflammation and cancers. In humans, Helicobacter infection is mainly related to H. pylori, a gastric pathogen infecting more than half of the world's population, leading to chronic inflammation of the gastric mucosa that can evolve into two types of gastric cancers: gastric adenocarcinomas and gastric MALT lymphoma. In addition, H. pylori but also non-H. pylori Helicobacter infection has been associated with many extra-gastric malignancies. This review focuses on H. pylori and its role in gastric cancers and extra-gastric diseases, as well as malignancies induced by non-H. pylori Helicobacters. Their different virulence factors and their involvement in carcinogenesis is discussed. This review highlights the importance of both gastric and enterohepatic Helicobacters in gastrointestinal and liver cancers.