Emerging Role of Infectious Etiologies in the Pathogenesis of Marginal Zone B-cell Lymphomas

Abstract

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 Sj€ ogren 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-kB) 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.

Eradication of Hepatitis C Virus Is Associated With Reduction in Hematologic Malignancies: Major Differences Between Interferon and Direct‐Acting Antivirals

“…Multiple observational studies have consistently reported an increased risk of certain B‐cell lymphomas with hepatitis C virus (HCV) infection . Chronic antigen stimulation of lymphocytes is a hypothesized mechanism in HCV‐associated lymphoma, followed by a second oncogenic or proliferative “hit” that may be antigen independent . Although not as strong and consistent as the associations with lymphoma, HCV has also been associated with many other hematologic malignancies, including myeloma, chronic lymphocytic leukemia, and myeloid leukemias, as well as with monoclonal gammopathy of unknown significance (MGUS), a premalignant precursor of multiple myeloma.…”

Geographical differences in survival of dogs with non‐Hodgkin lymphoma treated with aCHOPbased chemotherapy protocol

“…In humans, B‐cell lymphomas are thought to occasionally occur in individuals with chronic antigenic stimulation . The cellular signals from other cells in the inflammatory environment provide survival and proliferation signals that may lead to malignant transformation or sustained tumour cell growth . Though these causes more often are described in terms of incidence, they may also play a role in the biologic activity of the tumours they cause.…”

Are We Nearing an Era of Chemotherapy-Free Management of Indolent Lymphoma?

“…A brief overview of such treatments is presented in this review, whereas new directions in other lymphoma subtypes are presented in this edition of CCR Focus (83)(84)(85)(86)(87). Among other promising approaches, combining anti-CD20 antibodies with IMiDs, mAbs directed against other surface antigens such as CD22, immunomodulatory antibodies such as PD-1, or inhibitors of the B-cell receptor (BCR) pathway is of paramount interest.…”