Immunological and molecular classification of mucosa-associated lymphoid tissue lymphoma.
Malignant B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type is now considered to be a tumor of marginal zone cells of native or, more frequently, acquired MALT. The relationship of MALT lymphoma to the normal counterpart population is acknowledged by the revised European-American classification of lymphoid neoplasms (R.E.A.L.). It fits into the extranodal subtype of marginal zone lymphoma listed as a distinct entity in this recent classification scheme. A typical feature of this lymphoma type is a close lymphocyte-epithelium interaction as reflected by lymphoepithelial lesions. The immunophenotype is characterized by the expression of Sig and B-cell-associated antigens and by the lack of CD5 and CD10. Frequent occurrence of trisomy 3 has been reported. There is now overwhelming evidence that low-grade MALT lymphomas are subject to immunologic drive. In the stomach, the presence of Helicobacter pylori and locally activated T cells appears to be critical for the growth of neoplastic cells. This finding is of clinical significance since the eradication of H. pylori has been shown to reverse low-grade MALT lymphoma.
Schmitt-Gräff
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Institut für Pathologie, Albert Ludwig Universität Freiburg, Germany.
D005770:Gastrointestinal Neoplasms / Q000145:classification / Q000473:pathology; D006801:Humans; D016130:Immunophenotyping; D016393:Lymphoma, B-Cell / Q000145:classification; D018442:Lymphoma, B-Cell, Marginal Zone / Q000145:classification* / Q000235:genetics / Q000276:immunology