API2-MALT1 fusion defines a distinctive clinicopathologic subtype in pulmonary extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.
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.
Okabe
Mitsukuni
M
Department of Pathology, Nagoya City University Medical School, Nagoya, Japan.
Inagaki
Hiroshi
H
Ohshima
Koichi
K
Yoshino
Tadashi
T
Li
Chunmei
C
Eimoto
Tadaaki
T
Ueda
Ryuzo
R
Nakamura
Shigeo
S
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
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