title: API2-MALT1 fusion defines a distinctive clinicopathologic subtype in pulmonary extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.
abstract: t(11;18)(q21;q21) is associated with mucosa-associated lymphoid tissue (MALT)-type lymphoma and results in API2-MALT1 fusion. However, its clinicopathologic significance remains unclarified. API2-MALT1 fusion is detected most frequently in MALT lymphomas primarily involving the lung. We therefore screened 51 cases of pulmonary MALT lymphoma for API2-MALT1 fusion, and studied its relationship with clinicopathologic factors including the immunohistochemical expression of BCL10, another MALT lymphoma-associated molecule. The API2-MALT1 fusion transcript was detected in 21 of 51 (41%) cases, and was correlated with the absence of any underlying autoimmune disease, and with a normal serum lactate dehydrogenase, a "typical" histology without marked plasmacytic differentiation or an increased number of large cells, and aberrant nuclear BCL10 expression. However, its prognostic impact was not identified in the limited follow-up (6 to 187 months, median 27). These data suggest that the API2-MALT1 fusion may be a causative gene abnormality unrelated to autoimmune disease. In addition, this alteration may define a homogeneous MALT lymphoma subtype that is clinically more indolent and histologically more "typical." Aberrant nuclear BCL10 expression may have a possible role as a tool to screen for this API2-MALT1 fusion. A large-scale study with a long follow-up is necessary to establish the prognostic significance of API2-MALT1 fusion.
authors.affiliation: Department of Pathology, Nagoya City University Medical School, Nagoya, Japan.
authors.forename: Mitsukuni
authors.initials: M
authors.lastname: Okabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inagaki
authors.forename: Koichi
authors.initials: K
authors.lastname: Ohshima
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yoshino
authors.forename: Chunmei
authors.initials: C
authors.lastname: Li
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Eimoto
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Ueda
authors.forename: Shigeo
authors.initials: S
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D020169:Caspases; D002880:Chromosomes, Human, Pair 11; D002887:Chromosomes, Human, Pair 18; D005260:Female; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology*; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein; D009363:Neoplasm Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014178:Translocation, Genetic
chemical_list: D051034:Inhibitor of Apoptosis Proteins; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D011506:Proteins; D007770:L-Lactate Dehydrogenase; D020169:Caspases; C400109:MALT1 protein, human; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein