John Libbey Eurotext

Hématologie

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Cytogenetic alterations in gastric MALT lymphomas: pathogenic significance and clinical correlations Volume 9, issue 2, Mars 2003

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Authors
Département de pathologie, hôpital Henri‐Mondor, Créteil, France

Extranodal marginal zone B‐cell lymphomas of MALT type arise most frequently in the gastric mucosa. These lymphomas derive from marginal zone B‐cells of reactive lymphoid follicles, that are usually acquired as a reaction to Helicobacter pylori infection. Two specific cytogenetic alterations have recently been identified in these lymphomas. Their molecular characterization has given major insights into the oncogenic pathways involved in this disease. The translocation t(1;14)(p22;q32) is a rather rare event and results in the juxtaposition of the coding region of the BCL10 gene to chromosome 14 under the control of the immunoglobulin heavy chain regulatory elements. The BCL10 gene encodes a cytoplasmic protein which plays a key role in connecting antigen receptor signaling in B and T lymphoid cells to NF‐κB activation. The translocation t(11;18)(q21;q21) can be detected in about 30% of gastric MALT lymphomas and results in the production of chimeric proteins that contain the BIR (Baculovirus IAP Repeat) domains of cIAP2 protein fused to the paracaspase domain of the MALT1 protein. These chimeric proteins are also able to induce NF‐κB transcriptional activity. Notably, these cytogenetic alterations are associated with an advanced‐stage disease and constitute a predictive factor of lymphoma persistance after Helicobacter pylori eradication. In this review, we discuss the recent molecular and cellular data and propose a pathogenic model associating these data to the clinical and histological aspects of this lymphoma subtype.