MALT Lymphoma as a Model of Chronic Inflammation-Induced Gastric Tumor Development

Reactive oxygen species and gastric carcinogenesis: The complex interaction between Helicobacter pylori and host

Helicobacter pylori (H. pylori) is a highly successful human pathogen that colonizes stomach in around 50% of the global population. The colonization of bacterium induces an inflammatory response and a substantial rise in the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), mostly derived from host neutrophils and gastric epithelial cells, which play a crucial role in combating bacterial infections. However, H. pylori has developed various strategies to quench the deleterious effects of ROS, including the production of antioxidant enzymes, antioxidant proteins as well as blocking the generation of oxidants. The host's inability to eliminate H. pylori infection results in persistent ROS production. Notably, excessive ROS can disrupt the intracellular signal transduction and biological processes of the host, incurring chronic inflammation and cellular damage, such as DNA damage, lipid peroxidation, and protein oxidation. Markedly, the sustained inflammatory response and oxidative stress during H. pylori infection are major risk factor for gastric carcinogenesis. In this context, we summarize the literature on H. pylori infection-induced ROS production, the strategies used by H. pylori to counteract the host response, and subsequent host damage and gastric carcinogenesis.

Characterization of LIMA1 and its emerging roles and potential therapeutic prospects in cancers

Actin is the most abundant and highly conserved cytoskeletal protein present in all eukaryotic cells. Remodeling of the actin cytoskeleton is controlled by a variety of actin-binding proteins that are extensively involved in biological processes such as cell motility and maintenance of cell shape. LIM domain and actin-binding protein 1 (LIMA1), as an important actin cytoskeletal regulator, was initially thought to be a tumor suppressor frequently downregulated in epithelial tumors. Importantly, the deficiency of LIMA1 may be responsible for dysregulated cytoskeletal dynamics, altered cell motility and disrupted cell-cell adhesion, which promote tumor proliferation, invasion and migration. As research progresses, the roles of LIMA1 extend from cytoskeletal dynamics and cell motility to cell division, gene regulation, apical extrusion, angiogenesis, cellular metabolism and lipid metabolism. However, the expression of LIMA1 in malignant tumors and its mechanism of action have not yet been elucidated, and many problems and challenges remain to be addressed. Therefore, this review systematically describes the structure and biological functions of LIMA1 and explores its expression and regulatory mechanism in malignant tumors, and further discusses its clinical value and therapeutic prospects.

Bilateral Cubital Lymphoma and Mycobacteriosis in a Salmon-Crested Cockatoo (Cacatua moluccensis)

A 32-year-old male salmon-crested cockatoo (Cacatua moluccensis) was diagnosed by cytology with bilateral cubital lymphoma and mycobacteriosis. Polymerase chain reaction assay testing confirmed Mycobacterium genavense. This patient was subsequently humanely euthanized. Postmortem histopathology confirmed both diagnoses with findings of multicentric lymphoma, acid-fast bacilli, and severe degenerative changes in all synovial joints examined. Immunohistochemical staining for paired box protein 5 of the cubital mass was positive for a high percentage of B-cell lymphocytes, consistent with B-cell lymphoma. This unusual case of two major diseases presenting concurrently in one patient raises the question of whether the pathogenesis could have an interdependent relationship. Mycobacteriosis, severe degenerative joint changes, or both may have stimulated lymphocytes, eventually leading to lymphoma. Additional screening and monitoring for comorbidities may be advised if 1 of these diseases are diagnosed in companion avian species.

Management of Extranodal Marginal Zone Lymphoma: Present and Upcoming Perspectives

Simple Summary

Extranodal marginal zone lymphoma distinguishes itself from other indolent lymphomas due to its unique pathophysiology and natural history. This is reflected in its management, where next to traditional treatment strategies such as observation, radiotherapy or chemotherapy, eradication of the causal agent and even surgery represent important aspects of therapy. This review focuses on the particular aspects of this indolent lymphoma that affect management and summarizes the current evidence and different guidelines.

Abstract

Extranodal marginal zone lymphoma (EMZL) encompasses a subgroup of non-Hodgkin lymphomas that often present with localized involvement and may manifest in a diversity of organs and tissues. EMZL pathogenesis is in some cases linked to chronic inflammation/infection, which may impose additional diagnostic and clinical challenges. The most studied and established connection is the presence of Helicobacter pylori in gastric EMZL. Due to its heterogeneity of presentation and intricate pathological features, treatment can be complex, and staging systems are decisive for the choice of therapy. Nevertheless, there is no consensus regarding the most suitable staging system, and recommendations vary among different countries. As a rule of thumb, in limited stages, a local therapy with surgery or radiation is the preferred option, and it is potentially curative. Of note, eradicating the causal agent may be an important step of treatment, especially in gastric EMZL, in which Helicobacter pylori eradication remains the first-line therapy for the majority of patients. In patients with more advanced stages, watch-and-wait is a valuable option, especially amongst those without clear indications for systemic therapy, and it may be carried on for several years. If watch-and-wait is not an option, systemic therapy may be needed. Even though several agents have been tested as monotherapy or in combination in recent years, there is no consensus regarding the first-line therapy, and decisions can vary depending on individual factors, such as age, clinical performance and stage. This review aims to discuss the several aspects of EMZL, including genetic milieu, pathogenesis and staging systems, that may influence the choice of therapy. In addition, we present a summary of evidence of several systemic therapies, compare different recommendations worldwide and discuss future perspectives and novelties in its therapy.

Discordant lymphomas of classic Hodgkin lymphoma and peripheral T-cell lymphoma following dupilumab treatment for atopic dermatitis

There have recently been a few case reports of cutaneous T-cell lymphomas following treatment of atopic dermatitis with dupilumab, which works binding to the interleukin (IL)-4 receptor and inhibiting the JAK/ STAT cascade located downstream of both IL-4 and IL-13. Here, we report the first case of Hodgkin lymphoma (HL) in a patient treated with dupilumab for one year. Based on multiple biopsies, this case was diagnosed as a rare combination of discordant lymphomas of HL and peripheral T-cell lymphoma. As both lymphomas are known to overexpress IL-13, future studies should carefully evaluate the effect of anti-IL-13 therapy. A literature review showed that dermatitis persisted or worsened in all reported lymphoma cases following dupilumab and cutaneous T-cell lymphoma was diagnosed within 2 years of the start of treatment with dupilumab. In these cases, with the addition of our own, the median interval was 12 months, and 31% needed multiple biopsies for diagnosis of lymphomas. Our results demonstrate a need to be alert to potential development of lymphomas associated with the IL-13 and IL-4 pathways in patients with poorly responsive atopic dermatitis receiving dupilumab, and to consider the possibility of composite or discordant lymphomas in diagnosis and treatment of lymphomas.

The Expression of IgG and IgG4 in Orbital MALT Lymphoma: The Similarities and Differences of IgG4-Related Diseases

Objective

This study aims to study the expression and role of IgG and IgG4 in orbital MALT lymphoma and to compare the characteristics of IgG4-related diseases.

Patients and Methods

Patients with orbital MALT lymphoma, treated in the West China Hospital of Sichuan University from 2012 to 2017, were enrolled in the current study. The immunological examination of the wax blocks of orbital masses was performed again and the expression level of IgG and IgG4 in pathological tissue was analyzed.

Results

The results presented that the positive rates of IgG and IgG4 in the cases of orbital MALT lymphoma were 90.91% and 61.98% respectively, of which IgG4/IgG >40% accounted for 49.33%. The positive rates of IgG and IgG4 in relapse cases were 94.60% and 70.27% respectively, and IgG4/IgG >40% accounted for 42.31%. There was no significant change in the expression of IgG and IgG4 in cases of lymphoproliferation converting to MALT lymphoma whereas, in cases of MALT lymphoma postoperatively converting to lymphoproliferation, there was an increase in IgG and IgG4 expression, with the change of IgG4 being significant.

Conclusion

IgG and IgG4 have a high correlation in the pathogenesis of MALT lymphoma and may even play an important role in the transformation of MALT lymphoma into orbital lymphoid hyperplasia. Given the association of IgG4 with inflammation and tumors and as an important diagnostic indicator for IgG4-RD and IgG4-related ophthalmic diseases, IgG4 may play an important role in these diseases.

Myeloid-Derived Suppressor Cells and γδT17 Cells Contribute to the Development of Gastric MALT Lymphoma in H. felis-Infected Mice

Helicobacter-induced chronic inflammation and immune disorders are closely associated with the development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Myeloid-derived suppressor cells (MDSCs) exhibit strong immunosuppressive properties and promote the growth of various solid tumors. However, the role of MDSCs in the development of MALT lymphoma has not been elucidated so far. We detected significant infiltration and enrichment of MDSCs in patients with MALT lymphoma, as well in Helicobacter felis-infected mouse model of gastric MALT lymphoma. In addition, the expression of arginase-1 and inducible nitric oxide synthase was significantly elevated both in gastric MALT lymphoma tissues and H. felis-infected stomach. Persistent H. felis infection closely reproduced the development of gastric MALT lymphoma and was accompanied by increased numbers of γδT17 cells. Accumulation of γδT17 cells was also validated in the human gastric MALT lymphoma tissues. Furthermore, the elevated cytokines interleukin-23 and interleukin-1β, as well as chemokines CCL20/CCR6, may be involved in the accumulation of γδT17 cells and the subsequent immunosuppression. These findings highlight the role of MDSCs and γδT17 cells in immune dysregulation during gastric MALT lymphoma development and their potential as therapeutic targets.