A20, ABIN-1/2, and CARD11 mutations and their prognostic value in gastrointestinal diffuse large B-cell lymphoma.
OBJECTIVE
Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of aggressive lymphomas with the activated B-cell-like subtype characterized by constitutive NF-κB activation. Activating mutations of CARD11 and inactivating mutations of A20 are frequent events in DLBCL. However, the full extent of genetic alterations in the NF-κB pathway regulators and their potential prognostic value in DLBCL remain to be investigated. We investigated the genetic abnormalities of CARD11, A20, and ABIN-1/2/3 (the A20 binding inhibitor of NF-κB) and their clinicopathologic correlation in gastrointestinal DLBCL.


METHODS
The somatic mutation and copy number changes of CARD11, A20, and ABIN-1/2/3 were investigated in 71 gastrointestinal DLBCLs by PCR/sequencing, and interphase FISH/array comparative genomic hybridization, respectively. The mutations identified were functionally characterized by NF-κB reporter assays and immunoprecipitation experiments.


RESULTS
Recurrent somatic mutations were found in CARD11 (10%), A20 (17%), ABIN-1 (4%), and ABIN-2 (3%), but not in ABIN-3. In comparison with the wild-type, all CARD11 mutants were potent NF-κB activators in vitro. On the basis of the destructive nature of the observed mutations, and the findings by reporter assays and immunoprecipitation studies, most if not all of the somatic mutations that were seen in A20, ABIN-1, and ABIN-2 could impair their normal functions. Among these genetic abnormalities, A20 somatic mutation was significantly associated with both poor overall survival and event-free survival.


CONCLUSIONS
We show further evidence of NF-κB pathway genetic abnormalities in DLBCL, which are potentially valuable in the prognosis and design of future therapeutic strategies.
Division of Molecular Histopathology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom.
Gehong
G
Dong
Estelle
E
Chanudet
Naiyan
N
Zeng
Alex
A
Appert
Yun-Wen
YW
Chen
Wing-Yan
WY
Au
Rifat A
RA
Hamoudi
A James
AJ
Watkins
Hongtao
H
Ye
Hongxiang
H
Liu
Zifen
Z
Gao
Shih-Sung
SS
Chuang
Gopesh
G
Srivastava
Ming-Qing
MQ
Du
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D053468:CARD Signaling Adaptor Proteins / Q000235:genetics*; D054418:Chemokine CCL20 / Q000235:genetics*; D002869:Chromosome Aberrations; D004268:DNA-Binding Proteins / Q000235:genetics*; D005770:Gastrointestinal Neoplasms / Q000235:genetics*; D006162:Guanylate Cyclase / Q000235:genetics*; D006801:Humans; D047468:Immunoprecipitation; D017404:In Situ Hybridization, Fluorescence; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics*; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism; D011379:Prognosis; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA
D048868:Adaptor Proteins, Signal Transducing; D053468:CARD Signaling Adaptor Proteins; D054418:Chemokine CCL20; D004268:DNA-Binding Proteins; D016328:NF-kappa B; C117046:TNIP1 protein, human; C434062:TNIP2 protein, human; C426242:CARD11 protein, human; D006162:Guanylate Cyclase