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1.
Blood ; 135(4): 274-286, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31738823

RESUMO

Pediatric large B-cell lymphomas (LBCLs) share morphological and phenotypic features with adult types but have better prognosis. The higher frequency of some subtypes such as LBCL with IRF4 rearrangement (LBCL-IRF4) in children suggests that some age-related biological differences may exist. To characterize the genetic and molecular heterogeneity of these tumors, we studied 31 diffuse LBCLs (DLBCLs), not otherwise specified (NOS); 20 LBCL-IRF4 cases; and 12 cases of high-grade B-cell lymphoma (HGBCL), NOS in patients ≤25 years using an integrated approach, including targeted gene sequencing, copy-number arrays, and gene expression profiling. Each subgroup displayed different molecular profiles. LBCL-IRF4 had frequent mutations in IRF4 and NF-κB pathway genes (CARD11, CD79B, and MYD88), losses of 17p13 and gains of chromosome 7, 11q12.3-q25, whereas DLBCL, NOS was predominantly of germinal center B-cell (GCB) subtype and carried gene mutations similar to the adult counterpart (eg, SOCS1 and KMT2D), gains of 2p16/REL, and losses of 19p13/CD70. A subset of HGBCL, NOS displayed recurrent alterations of Burkitt lymphoma-related genes such as MYC, ID3, and DDX3X and homozygous deletions of 9p21/CDKN2A, whereas other cases were genetically closer to GCB DLBCL. Factors related to unfavorable outcome were age >18 years; activated B-cell (ABC) DLBCL profile, HGBCL, NOS, high genetic complexity, 1q21-q44 gains, 2p16/REL gains/amplifications, 19p13/CD70 homozygous deletions, and TP53 and MYC mutations. In conclusion, these findings further unravel the molecular heterogeneity of pediatric and young adult LBCL, improve the classification of this group of tumors, and provide new parameters for risk stratification.

2.
Int J Cancer ; 145(11): 3078-3088, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31044434

RESUMO

Diffuse large B-cell lymphoma (DLBCL) is up to 17-fold more likely to occur, follows a more aggressive clinical course and frequently presents at advanced stages in HIV infected (+) individuals compared to HIV negative (-) individuals. However, the molecular pathology underpinning the clinical features of DLBCL in HIV(+) patients relative to the general population is poorly understood. We performed a retrospective study examining the transcriptional, genomic and protein expression differences between HIV(+) and HIV(-) germinal center B-cell (GCB) DLBCL cases using digital gene expression analysis, array comparative genomic hybridization (CGH) and immunohistochemistry (IHC). Genes associated with cell cycle progression (CCNA2, CCNB1, CDC25A, E2F1), DNA replication (MCM2, MCM4, MCM7) and DNA damage repair, including eight Fanconi anemia genes (FANCA, FANCD1/BRCA2, FANCE, FANCG, FANCR/RAD51, FANCS/BRCA1, FANCT/UBE2T, FANCV/MAD2L2), were significantly increased in HIV(+) GCB-DLBCL tumors compared to HIV(-) tumors. In contrast, genes associated with cell cycle inhibition (CDKN1A, CDKN1B) as well as apoptosis regulating BCL2 family members (BCL2, BAX, BIM, BMF, PUMA) were significantly decreased in the HIV(+) cohort. BCL2 IHC confirmed this expression. Array CGH data revealed that HIV(+) GCB-DLBCL tumors have fewer copy number variations than their HIV(-) counterparts, indicating enhanced genomic stability. Together, the results show that HIV(+) GCB-DLBCL is a distinct molecular malignancy from HIV(-) GCB-DLBCL; with an increased proliferative capacity, confirmed by Ki67 IHC staining, and enhanced genomic stability, the latter of which is likely related to the enhanced expression of DNA repair genes.


Assuntos
Reparo do DNA , Perfilação da Expressão Gênica/métodos , Instabilidade Genômica , Infecções por HIV/genética , Linfoma Difuso de Grandes Células B/genética , Adulto , Idoso , Hibridização Genômica Comparativa , Feminino , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Humanos , Imuno-Histoquímica , Linfoma Difuso de Grandes Células B/virologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
3.
Blood ; 132(22): 2401-2405, 2018 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-30257882

RESUMO

Primary mediastinal large B-cell lymphoma (PMBCL) is recognized as a distinct entity in the World Health Organization classification. Currently, the diagnosis relies on consensus of histopathology, clinical variables, and presentation, giving rise to diagnostic inaccuracy in routine practice. Previous studies have demonstrated that PMBCL can be distinguished from subtypes of diffuse large B-cell lymphoma (DLBCL) based on gene expression signatures. However, requirement of fresh-frozen biopsy material has precluded the transfer of gene expression-based assays to the clinic. Here, we developed a robust and accurate molecular classification assay (Lymph3Cx) for the distinction of PMBCL from DLBCL subtypes based on gene expression measurements in formalin-fixed, paraffin-embedded tissue. A probabilistic model accounting for classification error, comprising 58 gene features, was trained on 68 cases of PMBCL and DLBCL. Performance of the model was subsequently evaluated in an independent validation cohort of 158 cases and showed high agreement of the Lymph3Cx molecular classification with the clinicopathological diagnosis of an expert panel (frank misclassification rate, 3.8%). Furthermore, we demonstrate reproducibility of the assay with 100% concordance of subtype assignments at 2 independent laboratories. Future studies will determine Lymph3Cx's utility for routine diagnostic purposes and therapeutic decision making.


Assuntos
Perfilação da Expressão Gênica , Linfoma Difuso de Grandes Células B/diagnóstico , Linfoma não Hodgkin/diagnóstico , Neoplasias do Mediastino/diagnóstico , Estudos de Coortes , Regulação Neoplásica da Expressão Gênica , Humanos , Linfoma Difuso de Grandes Células B/classificação , Linfoma Difuso de Grandes Células B/genética , Linfoma não Hodgkin/classificação , Linfoma não Hodgkin/genética , Neoplasias do Mediastino/classificação , Neoplasias do Mediastino/genética , Mediastino/patologia , Inclusão em Parafina
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