Reappraisal of BCL3 as a molecular marker of anaplastic large cell lymphoma.
The BCL3 gene was initially discovered through its involvement in a recurring translocation, t(14;19)(q32;q13), which is found in some patients with B-cell chronic lymphocytic leukemia (B-CLL). The translocation leads to the juxtaposition of BCL3 to the immunoglobulin heavy chain gene locus, resulting in high-level expression of the BCL3 transcript. The Bcl-3 protein includes 7 tandem copies of the ankyrin repeat element in the central domain, a structure that is characteristic of the IkappaB family of inhibitors of the nuclear factor kappaB transcription factors. Anaplastic large cell lymphoma (ALCL) is a subtype of aggressive non-Hodgkin's lymphoma that is characterized by expression of CD30 and the NPM/ALK chimeric protein, which is generated by t(2;5)(p23;q35). We compared the gene expression profiles of ALCL with those of another CD30+ neoplasm, Hodgkin's disease (HD), and found that BCL3 is expressed at higher levels in ALCL than in HD. A comparison by real-time polymerase chain reaction assay revealed that t(2;5)+ ALCL expresses a high level of BCL3 messenger RNA relative to the levels expressed in other hematologic tumors, and the level in ALCL is comparable to or even higher than that in t(14;19)+ B-CLL. An immunohistochemical analysis of ALCL tumor tissues showed that the lymphoma cells exhibited strong nuclear staining by a monoclonal antibody against Bcl-3. We suggest that Bcl-3 sequestrates the (p50)2 homodimer to the nucleus and that the kappaB sites are occupied by the (p50)2/Bcl-3 ternary complex. Future studies should identify the relationships among the 3 independent molecules (ie, NPM/ALK, CD30, and Bcl-3) that are activated in t(2;5)+ ALCL.
Department of Internal Medicine, Takeda General Hospital, 28-1 Mori-minami-cho, Ishida, Fushimi-ku, Kyoto 601-1495, Japan. hohno@k2.dion.ne.jp
Hitoshi
H
Ohno
Momoko
M
Nishikori
Yoshitomo
Y
Maesako
Hironori
H
Haga
D000081242:B-Cell Lymphoma 3 Protein; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D002877:Chromosomes, Human / Q000235:genetics* / Q000378:metabolism; D015973:Gene Expression Regulation, Leukemic / Q000235:genetics*; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors; D014178:Translocation, Genetic / Q000235:genetics*
D000081242:B-Cell Lymphoma 3 Protein; C000631344:BCL3 protein, human; D014408:Biomarkers, Tumor; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors