RESUMO
The histone methyltransferase EZH2 has an essential role in the development of follicular lymphoma (FL). Recurrent gain-of-function mutations in EZH2 have been described in 25% of FL patients and induce aberrant methylation of histone H3 lysine 27 (H3K27). We evaluated the role of EZH2 genomic gains in FL biology. Using RNA sequencing, Sanger sequencing and SNP-arrays, the mutation status, copy-number and gene-expression profiles of EZH2 were assessed in a cohort of 159 FL patients from the PRIMA trial. Immunohistochemical (IHC) EZH2 expression (n=55) and H3K27 methylation (n=63) profiles were also evaluated. In total, 37% of patients (59/159) harbored an alteration in the EZH2 gene (mutation n=46, gain n=23). Both types of alterations were associated with highly similar transcriptional changes, with increased proliferation programs. An H3K27me3/me2 IHC score fully distinguished mutated from wild-type samples, showing its applicability as surrogate for EZH2 mutation analysis. However, this score did not predict the presence of gains at the EZH2 locus. The presence of an EZH2 genetic alteration was an independent factor associated with a longer progression-free survival (hazard ratio 0.58, 95% confidence interval 0.36-0.93, P=0.025). We propose that the copy-number status of EZH2 should also be considered when evaluating patient stratification and selecting patients for EZH2 inhibitor-targeted therapies.
Assuntos
Proteína Potenciadora do Homólogo 2 de Zeste/genética , Histona-Lisina N-Metiltransferase/genética , Linfoma Folicular/genética , Adulto , Idoso , Linhagem Celular Tumoral , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Histona Metiltransferases , Humanos , Linfoma Folicular/tratamento farmacológico , Linfoma Folicular/patologia , Masculino , Metilação/efeitos dos fármacos , Pessoa de Meia-Idade , Mutação/genética , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de RNARESUMO
This report retrospectively analyzed the outcome of 91 patients aged 60 years or older with refractory/relapsed (R/R) classical Hodgkin's lymphoma (cHL) who underwent autologous stem cell transplantation (ASCT) between 1992 and 2013 and were reported to the French Society of Bone Marrow Transplantation and Cell Therapies registry. The median age at transplant was 63 years. The majority of patients exhibited disease chemosensitivity to salvage treatment (57 complete responses, 30 partial responses, 1 progressive disease and 3 unknown). The most frequent conditioning regimen consisted of BCNU, cytarabine, etoposide, melphalan (BEAM) chemotherapy (93%). With a median follow-up of 54 months, 5-year estimates of overall survival (OS) and progression free survival (PFS) for the entire group were 67 and 54%, respectively. Despite the missing data, in univariate analysis, the number of salvage chemotherapy lines (1-2 versus ⩾3) significantly influenced the OS, unlike the other prognostic factors (stage III-IV at relapse, disease status before ASCT and negative positron emission tomography (PET) scan) encountered in younger patients. In spite of its limitations, this retrospective study with a long-term follow-up suggests that ASCT is a valid treatment option for chemosensitive R/R cHL in selected elderly patients, with an acceptable rate of toxicity.
Assuntos
Transplante de Células-Tronco Hematopoéticas/métodos , Doença de Hodgkin/terapia , Terapia de Salvação/métodos , Fatores Etários , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Feminino , Seguimentos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/mortalidade , Doença de Hodgkin/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Terapia de Salvação/mortalidade , Análise de Sobrevida , Transplante AutólogoAssuntos
Bioensaio , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Leucemia/diagnóstico , Leucemia/genética , Proteínas de Fusão Oncogênica/análise , Doença Aguda , Sequência de Bases , Cromossomos Humanos Par 15 , Cromossomos Humanos Par 17 , Cromossomos Humanos Par 21 , Análise Citogenética , Sequenciamento de Nucleotídeos em Larga Escala/instrumentação , Humanos , Leucemia/patologia , Dados de Sequência Molecular , Sondas de Oligonucleotídeos/síntese química , Proteínas de Fusão Oncogênica/genética , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Translocação GenéticaRESUMO
In diffuse large B-cell lymphomas (DLBCL), a recurrent deletion of the 19p13 region has recently been described. CD70 and TNFSF9 genes are suspected tumor suppressor genes, but previous studies suggest an oncogenic role for CD70. Therefore, we studied the consequences of variation in CD70 copy number and epigenetic modifications on CD70 expression. Copy-number variation was investigated in 144 de novo DLBCL tissues by comparative genomic hybridization array and quantitative multiplex PCR. Gene expression was assessed by quantitative RT-PCR, and CD70 promoter methylation was determined by pyrosequencing. The 19p13.3.2 region was deleted in 21 (14.6%) cases, which allowed the minimal commonly deleted region of 57 Kb that exclusively includes the CD70 gene to be defined. Homozygous deletions were observed in four (2.7%) cases, and acquired single-nucleotide variations of CD70 were detected in nine (6.3%) cases. CD70 was highly expressed in both germinal centre B-cell-like (GCB) and activated B-cell-like (ABC) DLBCL compared to normal tissue, with distinct molecular mechanisms of mRNA expression regulation. A gene dosage effect was observed in the GCB subtype, whereas promoter methylation was the predominant mechanism of down regulation in the ABC subtype. However, high CD70 expression levels correlated to shorter overall survival in both the GCB (P = 0.0021) and the ABC (P =0.0158) subtypes. In conclusion, CD70 is targeted by recurrent deletions, somatic mutations and promoter hypermethylation, but its high level of expression is related to an unfavorable outcome, indicating that this molecule may constitute a potential therapeutic target in selected DLBCL.
Assuntos
Ligante CD27/genética , Variações do Número de Cópias de DNA/genética , Metilação de DNA/genética , Linfoma Difuso de Grandes Células B/genética , Ligante CD27/isolamento & purificação , Pontos de Quebra do Cromossomo , Deleção Cromossômica , Regulação Neoplásica da Expressão Gênica , Humanos , Hibridização in Situ Fluorescente , Linfoma Difuso de Grandes Células B/patologia , Regiões Promotoras Genéticas , Análise de SobrevidaRESUMO
Gene expression profiling has identified two major molecular subtypes of diffuse large B-cell lymphoma (DLBCL) that are histologically indistinguishable but differ in cure rates. Here, we investigated whether the isotype of the B-cell receptor (BCR) expressed by the tumoral cells correlated with the molecular subtype and survival. Gene expression analysis clustered the 53 patients included in this study into three subgroups, 17 germinal center B-cell-like (GCB) cases, 26 activated B-cell-like (ABC) cases and 10 intermediate cases. The molecular subtype was correlated with the isotype, as 15/17 GCB cases expressed a secondary isotype (immunoglobulin (Ig)G or IgA), whereas 24/26 ABC cases expressed a primary isotype (IgM or IgD) (P<0.0001). There was a trend toward a worse outcome for patients with an ABC DLBCL and a shorter overall survival for patients with IgM+ tumor (P=0.21 and 0.014, respectively). Finally, fluorescence in situ hybridization (FISH) analysis revealed a striking asymmetric pattern, as the IGHM gene is conserved only on the productive IGH allele in most IgM+ tumors. Taken together, these data indicate that the isotype of the BCR is a reliable indicator for the GCB and ABC subtypes in DLBCL, and suggest that the conservation of an IgM is required for ABC DLBCL lymphomagenesis to occur.
