TY - JOUR
T1 - Differential expression of enhancer of zeste homolog 2 (EZH2) protein in small cell and aggressive B-cell non-Hodgkin lymphomas and differential regulation of EZH2 expression by p-ERK1/2 and MYC in aggressive B-cell lymphomas
AU - Tian, Xuejun
AU - Pelton, Ashley
AU - Shahsafaei, Ali
AU - Dorfman, David M.
N1 - Publisher Copyright:
© 2016 USCAP, Inc All rights reserved.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - EZH2, a member of the polycomb protein group, is an important methyltransferase that is overexpressed in various neoplasms. We found that in small cell B-cell lymphomas, EZH2 is expressed in <40% of neoplastic cells, with heterogenous signal intensity. In aggressive B-cell lymphomas, 70-100% of tumor cells were positive for EZH2 expression with high signal intensity, which correlated with a high proliferation rate. We investigated the potential signaling molecules that regulate EZH2 overexpression in aggressive B-cell lymphomas and found that 80% of cases of EZH2-positive diffuse large B-cell lymphoma show high p-ERK1/2 expression (average ∼57% tumor cell positivity). In contrast, only a small percentage of tumor cells (∼10%) show p-ERK1/2 expression in Burkitt lymphoma and double hit lymphoma. On average, 91 and 76% of neoplastic cells were positive for MYC expression in Burkitt lymphoma and double hit lymphoma, respectively, while only 20% neoplastic cells were positive for MYC expression in diffuse large B-cell lymphoma. None of the aggressive B-cell lymphomas showed significant p-STAT3 expression in EZH2-overexpressed cases. The correlation of EZH2 expression with aggressive behavior and proliferation rate in B-cell neoplasms suggests that this molecule may function as an oncogenic protein in these neoplasms, with possible regulation by different signaling cascades in different types of aggressive B-cell lymphomas: p-ERK-related signaling in diffuse large B-cell lymphoma, and MYC-related signaling in Burkitt lymphoma and double hit lymphoma. Furthermore, EZH2 and associated signaling cascades may serve as therapeutic targets for the treatment of aggressive B-cell lymphomas.
AB - EZH2, a member of the polycomb protein group, is an important methyltransferase that is overexpressed in various neoplasms. We found that in small cell B-cell lymphomas, EZH2 is expressed in <40% of neoplastic cells, with heterogenous signal intensity. In aggressive B-cell lymphomas, 70-100% of tumor cells were positive for EZH2 expression with high signal intensity, which correlated with a high proliferation rate. We investigated the potential signaling molecules that regulate EZH2 overexpression in aggressive B-cell lymphomas and found that 80% of cases of EZH2-positive diffuse large B-cell lymphoma show high p-ERK1/2 expression (average ∼57% tumor cell positivity). In contrast, only a small percentage of tumor cells (∼10%) show p-ERK1/2 expression in Burkitt lymphoma and double hit lymphoma. On average, 91 and 76% of neoplastic cells were positive for MYC expression in Burkitt lymphoma and double hit lymphoma, respectively, while only 20% neoplastic cells were positive for MYC expression in diffuse large B-cell lymphoma. None of the aggressive B-cell lymphomas showed significant p-STAT3 expression in EZH2-overexpressed cases. The correlation of EZH2 expression with aggressive behavior and proliferation rate in B-cell neoplasms suggests that this molecule may function as an oncogenic protein in these neoplasms, with possible regulation by different signaling cascades in different types of aggressive B-cell lymphomas: p-ERK-related signaling in diffuse large B-cell lymphoma, and MYC-related signaling in Burkitt lymphoma and double hit lymphoma. Furthermore, EZH2 and associated signaling cascades may serve as therapeutic targets for the treatment of aggressive B-cell lymphomas.
UR - http://www.scopus.com/inward/record.url?scp=84973595816&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84973595816&partnerID=8YFLogxK
U2 - 10.1038/modpathol.2016.114
DO - 10.1038/modpathol.2016.114
M3 - Article
C2 - 27282353
AN - SCOPUS:84973595816
SN - 0893-3952
VL - 29
SP - 1050
EP - 1057
JO - Modern Pathology
JF - Modern Pathology
IS - 9
ER -