BCL-2 is consistently expressed in hyperplastic marginal zones of the spleen, abdominal lymph nodes, and ileal lymphoid tissue.
BCL-2 is an antiapoptotic protein overexpressed in follicular lymphomas, principally as a result of the t(14;18)(q32;q21), and useful in distinguishing follicular lymphoma (usually BCL-2 positive) from follicular hyperplasia (BCL-2 negative). BCL-2 is also overexpressed in other lymphoma types without the t(14;18), including marginal zone B-cell lymphoma, because of other, poorly understood mechanisms. It has been suggested that BCL-2 immunoreactivity can distinguish between malignant (BCL-2 positive) and reactive (BCL-2 negative) marginal zone B cells. In this study, we evaluated 26 spleen, 10 abdominal lymph node, and 3 ileum specimens with marginal zone B-cell hyperplasia for BCL-2 expression immunohistochemically. We also analyzed these cases using polymerase chain reaction methods to evaluate for the presence of clonal rearrangements of the immunoglobulin heavy chain gene (IgH) using consensus V FRIII and J region primers, and the t(14;18) involving both the major breakpoint and the minor cluster regions of the bcl-2 gene. All (100%) cases of splenic, abdominal lymph node, and ileal marginal zone hyperplasia displayed strong BCL-2 reactivity in the marginal zone B cells. In all cases analyzed, IgH polymerase chain reaction demonstrated a polyclonal pattern, and bcl-2/JH DNA fusion sequences were not detected. Our results indicate that BCL-2 is consistently expressed by reactive marginal zone B cells of the spleen, abdominal lymph nodes, and ileal lymphoid tissue and should not be used as a criterion for discriminating between benign and malignant marginal zone B-cell proliferations involving these sites.
Meda
Brenton A
BA
Division of Pathology, University of Utah Health Science Center, Salt Lake City, Utah 84132, USA.
Frost
Michael
M
Newell
James
J
Bohling
Sandra D
SD
Huebner-Chan
David R
DR
Perkins
Sherrie L
SL
Lim
Megan S
MS
Medeiros
L Jeffrey
LJ
Elenitoba-Johnson
Kojo S J
KS
D000005:Abdomen / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D001402:B-Lymphocytes / Q000378:metabolism / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002999:Clone Cells; D004247:DNA / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain / Q000235:genetics; D006801:Humans; D006965:Hyperplasia; D007082:Ileum / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000378:metabolism* / Q000473:pathology; D008221:Lymphoid Tissue / Q000378:metabolism*; D016393:Lymphoma, B-Cell / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D013154:Spleen / Q000378:metabolism* / Q000473:pathology; D014178:Translocation, Genetic
D019253:Proto-Oncogene Proteins c-bcl-2; D004247:DNA