Usefulness of HGAL and LMO2 immunohistochemistry in the identification of follicular lymphomas of the non-gastric gastrointestinal tract.
BACKGROUND
We studied the sensitivity of 2 relatively new markers of germinal center B-cell origin, namely human germinal center-associated lymphoma (HGAL) and Lim-only transcription factor 2 (LMO2), in the identification of follicular lymphomas (FLs) of the nongastric gastrointestinal (GI) tract.


METHODS
We retrospectively reviewed cases of endoscopically derived primary, nongastric GI lymphomas including FL, grade 1 or 2, and extranodal marginal zone lymphoma (ENMZL) of mucosa-associated lymphoid tissue, classified based on morphologic features and immunohistochemical analysis. HGAL and LMO2 immunohistochemical stains were then prospectively performed in each case. When discrepant immunohistochemical results were obtained, fluorescent in situ hybridization was performed for t(14;18) IGH/BCL2 and IGH rearrangement using a dual color fusion and a dual color break-apart probe, respectively.


RESULTS
All but one of the CD10-negative ENMZL cases were negative for both HGAL and LMO2. One case originally classified as ENMZL was positive for both HGAL and LMO2. Fluorescent in situ hybridization did not detect either t(14;18) IGH/BCL2 or IGH rearrangement in this case. It is likely, based on positivity of 2 established germinal center B-cell markers, that this represents a FL which was originally misclassified as an ENMZL based on CD10 negativity. Of the cases of FL (all CD10 and/or BCL-6 positive), 8 (80%) were positive for both HGAL and LMO2.


CONCLUSIONS
Although HGAL and LMO2 did not demonstrate an increased sensitivity in the identification of FL of the nongastric GI tract in this series, they still were helpful in the reclassification of one of our cases, and may therefore be useful adjuncts in the identification of FL of the nongastric GI tract.
Department of Pathology, University of Miami, Miami, FL 33136, USA.
Jennifer
J
Chapman-Fredricks
Sheren F
SF
Younes
Yao-Shan
YS
Fan
Jose D
JD
Sandoval-Sus
Yasodha
Y
Natkunam
Izidore S
IS
Lossos
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D007414:Intestinal Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins / Q000235:genetics*; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D008224:Lymphoma, Follicular / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D008297:Male; D008840:Microfilament Proteins; D008875:Middle Aged; D060787:Neoplasm Grading; D009363:Neoplasm Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D014178:Translocation, Genetic
D048868:Adaptor Proteins, Signal Transducing; C582872:BCL2-IgH fusion protein, human; D014408:Biomarkers, Tumor; C476824:GCSAM protein, human; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; C085117:LMO2 protein, human; D008840:Microfilament Proteins; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D011518:Proto-Oncogene Proteins