[Analysis of bcl-6 protein expression and gene rearrangement in diffuse large B-cell lymphoma].
OBJECTIVE
To investigate bcl-6 protein expression and gene rearrangement patterns in diffuse large B-cell lymphoma (DLBCL) and their clinicopathologic significance.


METHODS
Immunohistochemical studies for bcl-6 and CD10 proteins were performed on 51 cases of DLBCL paraffin-embedded tissues (including 22 nodal samples and 29 extranodal samples) and 10 cases of reactive lymphoid hyperplasia (RLH) paraffin-embedded tissues. Interphase fluorescence in-situ hybridization (FISH) with dual color breakapart probe was also used to identify rearrangement of bcl-6 gene in 32 cases of nodal DLBCL tissues (including 22 paraffin-embedded samples and 10 fresh samples) and 5 cases of RLH paraffin-embedded tissues.


RESULTS
(1) The rates of bcl-6 protein expression in nodal DLBCL, extranodal DLBCL and RLH were 72.7% (16/22), 75.9% (22/29) and 100.0% (10/10) respectively. The rates of CD10 expression were 40.9% (9/22), 41.4% (12/29) and 100.0% (10/10) respectively. All lymphoma samples which expressed CD10 also showed co-expression of bcl-6 protein. (2) The co-expression of bcl-6 and CD10 was observed in 40.9% (9/22) nodal DLBCL and 41.4% (12/29) extranodal DLBCL. Low clinical stage (stage I and II) was more frequently observed in cases with co-expression of bcl-6 and CD10 (P < 0.05). (3) The rates of bcl-6 gene rearrangement in nodal DLBCL was 28.1% (9/32), with 27.3% (6/22) in paraffin-embedded tissues and 30.0% (3/10) in fresh tissues. There was no statistically significant difference found between the two groups (P > 0.05). Bcl-6 gene rearrangement was not found in all the 5 cases of RLH, and there was a significant difference between RLH and DLBCL (P < 0.05).


CONCLUSIONS
The rate of bcl-6 protein expression is high in DLBCL cases, and the detection of bcl-6 and CD10 protein co-expression may help in the diagnosis and differential diagnosis of DLBCL. Those DLBCL cases with co-expression of bcl-6 and CD10 may also have a better prognostic implication. On the other hand, bcl-6 gene rearrangement can be identified by interphase FISH with dual color breakapart probe in both paraffin-embedded and fresh lymphoma tissues.
Min
Da-liu
DL
Laboratory of Molecular Pathology, Cancer Hospital of Fudan University, Shanghai 200032, China.
Xia
Hai-long
HL
Zhou
Xiao-yan
XY
Sun
Meng-hong
MH
Yang
Wen-tao
WT
Zhang
Tai-ming
TM
Zheng
Ai-hua
AH
Shi
Da-ren
DR
D003937:Diagnosis, Differential; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D016393:Lymphoma, B-Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015260:Neprilysin / Q000378:metabolism; D051560:Proto-Oncogene Proteins c-bcl-6 / Q000235:genetics / Q000378:metabolism*; D019310:Pseudolymphoma / Q000235:genetics
D051560:Proto-Oncogene Proteins c-bcl-6; D015260:Neprilysin