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1.
BMC Med Educ ; 24(1): 279, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38494509

RESUMO

BACKGROUND: The desire to die can occur in palliative care patients with a prevalence of up to 22%. Not every desire to die is accompanied by a pressure to act, but usually by a burden that can arise from various factors. To address this burden appropriately, health care workers should be trained. Based on an evaluated course on handling the desire to die, an elective course for medical students was developed and evaluated. In order to identify the impact of the elective course's content, a comparison of attitudes towards assisted dying with two other participant groups was conducted. Therefore, three questions from the evaluation of the elective course were used. METHOD: Online evaluation of the elective and questions addressing attitude were assessed using a five-point Likert scale. The specific outcome-based assessment was determined using the Comparative Self-Assessment Gain. The main participant group (group 1) were students who took the elective. The additional survey on attitudes towards assisted dying included undergraduate medical students who had taken compulsory palliative care courses (group 2) and physicians who had taken an introductory course in intensive care or emergency medicine (group 3). RESULTS: Group 1 (n = 13, response rate rr = 86.7%) was very satisfied with the blended learning format (100%) and the course itself (100%). They were able to deepen their knowledge (81.0%) and train skills (71.2%) through the course. In the additional surveys, there were 37 students in group 2 (rr = 66.1%) and 258 physicians in group 3 (rr = 73.6%). Willingness to assist with or accompany the various options for assisted dying varied according to the type of assistance. Among the participants, it can be summarised that the highest willingness was shown by the students of group 2 followed by the physicians of group 3 and the students of group 1. CONCLUSIONS: A course on handling the desire to die of palliative patients can deepen knowledge and train communication skills and thus support self-confidence. Dealing with the background of the desire to die, knowledge about assisted dying, but also one's own attitudes and responsibilities can influence the attitude towards assisted dying.


Assuntos
Medicina de Emergência , Estudantes de Medicina , Humanos , Cuidados Críticos , Pessoal de Saúde , Conhecimento
2.
Leukemia ; 32(1): 92-101, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28659618

RESUMO

Classical Hodgkin lymphoma (cHL) and anaplastic large cell lymphoma (ALCL) feature high expression of activator protein-1 (AP-1) transcription factors, which regulate various physiological processes but also promote lymphomagenesis. The AP-1 factor basic leucine zipper transcription factor, ATF-like 3 (BATF3), is highly transcribed in cHL and ALCL; however, its functional importance in lymphomagenesis is unknown. Here we show that proto-typical CD30+ lymphomas, namely cHL (21/30) and primary mediastinal B-cell lymphoma (8/9), but also CD30+ diffuse large B-cell lymphoma (15/20) frequently express BATF3 protein. Mass spectrometry and co-immunoprecipitation established interactions of BATF3 with JUN and JUNB in cHL and ALCL lines. BATF3 knockdown using short hairpin RNAs was toxic for cHL and ALCL lines, reducing their proliferation and survival. We identified MYC as a critical BATF3 target and confirmed binding of BATF3 to the MYC promoter. JAK/STAT signaling regulated BATF3 expression, as chemical JAK2 inhibition reduced and interleukin 13 stimulation induced BATF3 expression in cHL lines. Chromatin immunoprecipitation substantiated a direct regulation of BATF3 by STAT proteins in cHL and ALCL lines. In conclusion, we identified STAT-mediated BATF3 expression that is essential for lymphoma cell survival and promoted MYC activity in cHL and ALCL, hence we recognized a new oncogenic axis in these lymphomas.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/genética , Doença de Hodgkin/genética , Linfoma Anaplásico de Células Grandes/genética , Proteínas Proto-Oncogênicas c-myc/genética , Fatores de Transcrição STAT/genética , Regulação para Cima/genética , Carcinogênese/genética , Carcinogênese/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Sobrevivência Celular , Regulação Neoplásica da Expressão Gênica/genética , Doença de Hodgkin/patologia , Humanos , Janus Quinase 2/genética , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/patologia , Linfoma Anaplásico de Células Grandes/patologia , Oncogenes/genética , Regiões Promotoras Genéticas/genética , RNA Interferente Pequeno/genética , Transdução de Sinais/genética , Fator de Transcrição AP-1/genética , Ativação Transcricional/genética
3.
Leukemia ; 30(12): 2283-2292, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27499139

RESUMO

A key feature of the adaptive immune system is the generation of memory B and T cells and long-lived plasma cells, providing protective immunity against recurring infectious agents. Memory B cells are generated in germinal center (GC) reactions in the course of T cell-dependent immune responses and are distinguished from naive B cells by an increased lifespan, faster and stronger response to stimulation and expression of somatically mutated and affinity matured immunoglobulin (Ig) genes. Approximately 40% of human B cells in adults are memory B cells, and several subsets were identified. Besides IgG+ and IgA+ memory B cells, ∼50% of peripheral blood memory B cells express IgM with or without IgD. Further smaller subpopulations have additionally been described. These various subsets share typical memory B cell features, but likely also fulfill distinct functions. IgM memory B cells appear to have the propensity for refined adaptation upon restimulation in additional GC reactions, whereas reactivated IgG B cells rather differentiate directly into plasma cells. The human memory B-cell pool is characterized by (sometimes amazingly large) clonal expansions, often showing extensive intraclonal IgV gene diversity. Moreover, memory B-cell clones are frequently composed of members of various subsets, showing that from a single GC B-cell clone a variety of memory B cells with distinct functions is generated. Thus, the human memory B-cell compartment is highly diverse and flexible. Several B-cell malignancies display features suggesting a derivation from memory B cells. This includes a subset of chronic lymphocytic leukemia, hairy cell leukemia and marginal zone lymphomas. The exposure of memory B cells to oncogenic events during their generation in the GC, the longevity of these B cells and the ease to activate them may be key determinants for their malignant transformation.


Assuntos
Linfócitos B/imunologia , Memória Imunológica , Linfócitos B/classificação , Linfócitos B/citologia , Humanos , Isotipos de Imunoglobulinas , Neoplasias/patologia
4.
Leukemia ; 30(4): 844-53, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26658840

RESUMO

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL)-a subtype of Hodgkin lymphoma (HL)-is characterized by a low content of tumor cells, the lymphocyte predominant (LP) cells. Transformation into diffuse large B-cell lymphoma (DLBCL) occurs in about 10% of patients. We performed whole-genome mutation analysis of the DLBCL components from two composite lymphomas consisting of clonally related NLPHL and DLBCL as a means to identify candidate tumor suppressor genes and oncogenes in NLPHL. The analysis of LP cells for selected mutations of the DLBCL revealed that most mutations are also present in the LP cells, indicating a close relationship between the two components. The analysis of 62 selected genes in NLPHL by targeted ultra-deep sequencing revealed three novel highly recurrently mutated genes (each mutated in ~50% of cases), that is, DUSP2, SGK1 and JUNB. SGK1 was expressed in the LP cells of primary NLPHL cases and in the NLPHL cell line DEV. Administration of an SGK1 inhibitor induced apoptosis in the NLPHL cell line DEV and the DLBCL cell line Farage, suggesting a pathogenetic role of SGK1 in the LP and DLBCL cells. In summary, the present study identifies SGK1, DUSP2 and JUNB as novel key players in the pathogenesis of NLPHL.


Assuntos
Fosfatase 2 de Especificidade Dupla/genética , Doença de Hodgkin/genética , Proteínas Imediatamente Precoces/genética , Mutação/genética , Proteínas Serina-Treonina Quinases/genética , Fatores de Transcrição/genética , Adulto , Análise Mutacional de DNA , Sequenciamento de Nucleotídeos em Larga Escala , Doença de Hodgkin/patologia , Humanos , Imunofenotipagem , Linfonodos/metabolismo , Linfonodos/patologia , Linfócitos/metabolismo , Linfócitos/patologia , Linfoma Folicular/genética , Linfoma Folicular/patologia , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico
5.
Leukemia ; 29(2): 456-63, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25027518

RESUMO

Follicular lymphoma (FL) with a t(14;18) is a B-cell neoplasm clinically characterized by multiple recurrencies. In order to investigate the clonal evolution of this lymphoma, we studied paired primary and relapse tumor samples from 33 patients with recurrent non-transformed t(14;18)-positive FL. We reconstructed phylogenetic trees of the evolution by taking advantage of the activation-induced cytidine deaminase (AID)-mediated somatic hypermutation (SHM) active in the germinal center reaction using sequences of the clonal VHDHJH rearrangements of the immunoglobulin heavy chain (IGH) locus. Mutational analysis of the IGH locus showed evidence for ongoing somatic mutation and for counter-selection of mutations affecting the BCR conformation during tumor evolution. We further followed evolutionary divergence by targeted sequencing of gene loci affected by aberrant SHM as well as of known driver genes of lymphomagenesis, and by array-based genome-wide chromosomal imbalance and DNA methylation analysis. We observed a wide spectrum of evolutionary patterns ranging from almost no evolution to divergent evolution within recurrent non-transformed t(14;18) FL. Remarkably, we observed a correlation of the magnitude of evolutionary divergence across all genetic and epigenetic levels suggesting co-evolution. The distribution of coding mutations in driver genes and the correlation with SHM suggest CREBBP and AID to be potential modifiers of genetic and epigenetic co-evolution in FL.


Assuntos
Epigênese Genética , Linfoma Folicular/genética , Linfoma Folicular/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Cromossomos/ultraestrutura , Biologia Computacional , Citidina Desaminase/genética , Metilação de DNA , Análise Mutacional de DNA , Epigenômica , Evolução Molecular , Deleção de Genes , Genômica , Humanos , Imunoglobulinas/imunologia , Pessoa de Meia-Idade , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Filogenia , Polimorfismo de Nucleotídeo Único , Receptores de Antígenos de Linfócitos B/genética , Recidiva , Translocação Genética
6.
Curr Mol Med ; 14(5): 580-97, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24894178

RESUMO

MicroRNAs (miRNAs) are a class of small (18~25 nucleotides long) non-coding RNAs that regulate gene expression on the post-transcriptional level. During the last decade, the field of miRNA research has been exponentially expanding, revealing the widespread role of these molecules in numerous biological processes. Aberrant miRNA expression has been documented in multiple haematologic malignancies, including B cell lymphomas. There is compelling evidence that miRNAs can function as oncogenes or tumor suppressor genes in lymphoid malignancies. In this review, we recapitulate the current knowledge of miRNA expression in B cell malignancies and discuss the accumulating evidence for a major role of miRNA deregulation in the development of B cell-derived lymphoid tumors.


Assuntos
Leucemia de Células B/genética , Linfoma/genética , MicroRNAs/genética , Animais , Regulação Neoplásica da Expressão Gênica/genética , Humanos
7.
Leukemia ; 27(3): 671-9, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23174882

RESUMO

A hallmark of classical Hodgkin lymphoma (cHL) is that the B-cell-derived Hodgkin and Reed-Sternberg (HRS) tumor cells have largely lost the B-cell-typical gene expression program. The factors causing this 'reprogramming' of HRS cells are only partly understood. As early B-cell factor 1 (EBF1), a major B-cell transcription factor, is downregulated in HRS cells, we analyzed whether this downregulation contributes to the lost B-cell phenotype and tested the consequences of EBF1 re-expression in cHL cell lines. EBF1 re-expression caused an upregulation of B-cell genes, such as CD19, CD79A and CD79B, although the B-cell genes FOXO1 and PAX5 remained lowly expressed. The re-expression of CD19, CD79A and CD79B occurred largely without demethylation of promoter CpG motifs of these genes. In the cHL cell line L-1236 fitness decreased after EBF1 re-expression. These data show that EBF1 has the ability to reintroduce part of the B-cell signature in cHL cell lines. Loss of EBF1 expression in HRS cells therefore contributes to their lost B-cell phenotype. Notably, in the cHL cell line KM-H2 destructive mutations were found in one allele of EBF1, indicating that genetic lesions may sometimes have a role in impairing EBF1 expression.


Assuntos
Linfócitos B/patologia , Biomarcadores Tumorais/genética , Metilação de DNA , Regulação Neoplásica da Expressão Gênica , Doença de Hodgkin/patologia , Células de Reed-Sternberg/patologia , Transativadores/metabolismo , Apoptose , Linfócitos B/metabolismo , Sequência de Bases , Biomarcadores Tumorais/metabolismo , Western Blotting , Proliferação de Células , Ilhas de CpG , Perfilação da Expressão Gênica , Doença de Hodgkin/genética , Doença de Hodgkin/metabolismo , Humanos , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Células de Reed-Sternberg/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência do Ácido Nucleico , Transativadores/genética
8.
Leukemia ; 26(7): 1654-62, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22307176

RESUMO

The precise molecular pathogenesis of splenic marginal zone lymphoma (SMZL) is still unknown. Clinical and epidemiological data suggest that chronic hepatitis C virus (HCV) infection may have an etiological role in a subset of cases.We performed a large-scale microRNA (miRNA) expression profiling analysis of 381 miRNAs by quantitative reverse transcription PCR (Q-RT-PCR) of 26 microdissected splenic tissue samples (7 HCV(+) SMZL; 8 HCV(-) SMZL and 11 non-neoplastic splenic controls). Single assay Q-RT-PCR and miRNA in situ hybridization (miRNA-ISH) were used to confirm the results in an independent cohort. Unsupervised hierarchical clustering of miRNA expression profiles demonstrated a distinct signature of SMZL compared with the normal splenic marginal zone. Supervised analysis revealed differentially expressed miRNAs, including miRNAs with previously recognized tumor suppressive or oncogenic potential. Five miRNAs were found significantly overexpressed in SMZL, including miR-21, miR-155 and miR-146a, whereas seven miRNAs showed significantly reduced expression, including miR-139, miR-345, miR-125a and miR-126. Furthermore, we identified miR-26b, a miRNA known to have tumor suppressive properties, as significantly downregulated in SMZL arising in HCV-positive patients (P=0.0016). In conclusion, there is a characteristic dysregulation of miRNA expression in SMZL with a possible implication in its molecular tumorigenesis.


Assuntos
Biomarcadores Tumorais/genética , Perfilação da Expressão Gênica , Hepacivirus/isolamento & purificação , Hepatite C Crônica/genética , Linfoma de Zona Marginal Tipo Células B/genética , MicroRNAs/genética , Neoplasias Esplênicas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Regulação Neoplásica da Expressão Gênica , Hepatite C Crônica/virologia , Humanos , Hibridização In Situ , Linfoma de Zona Marginal Tipo Células B/virologia , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Baço/metabolismo , Baço/patologia , Neoplasias Esplênicas/virologia , Adulto Jovem
10.
Leukemia ; 25(12): 1797-807, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21818113

RESUMO

Recent studies addressing the molecular characteristics of PCNSL, which is defined as malignant B-cell lymphoma with morphological features of DLBCL, have significantly improved our understanding of the pathogenesis of this lymphoma entity, which is associated with an inferior prognosis as compared with DLBCL outside the CNS. This unfavorable prognosis stimulated intense efforts to improve therapy and induced recent series of clinical studies, which addressed the role of radiotherapy and various chemotherapeutic regimens. This review combines the discussion of diagnosis, differential diagnosis and recent progress in studies addressing the molecular pathogenesis as well as therapeutic options in PCNSL.


Assuntos
Neoplasias do Sistema Nervoso Central/diagnóstico , Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/terapia , Humanos
11.
Leukemia ; 24(6): 1152-9, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20428196

RESUMO

Soluble or membrane-anchored ligands of NKG2D and their receptor have a critical role in the elimination of tumor cells and disease progression. Plasma samples of 98 patients with B-cell chronic lymphocytic leukemia (CLL) were analyzed with specific ELISA systems for soluble major histocompatibility complex class I-related chains (sMICA and sMICB) and UL-16-binding proteins (ULBP1, 2, and 3). The flow cytometric analysis of MICA on CLL cells and natural killer group 2 member D (NKG2D) receptors on NK cells was performed after thawing of frozen peripheral blood lymphocytes of CLL patients (N=51). Levels of sMICA, sMICB, and sULBP2 were significantly increased (P<0.001) compared with 48 controls, whereas sULBP1 3 were not detectable in patients and controls. Levels of sMICA>990 pg/ml (P=0.014), sMICB>200 pg/ml (P=0.0001), and sULBP2>105 pg/ml (P<0.0001) were associated with poor treatment-free survival (TFS). Neither MICA nor NKG2D expression could be related to clinical parameters. In multivariate analysis Binet stage (P=0.002), sULBP2 (P=0.002) and ZAP-70 (P=0.002) were independent predictive factors for TFS. In patients with Binet stage A, sULBP2 levels>105 pg/ml were strongly associated (P=0.0025) with poor TFS. Our data show that soluble but not membrane-anchored NKG2D ligands or receptors are of prognostic significance in CLL. Moreover, sULBP2 seems to be useful to identify early-stage patients with risk of disease progression.


Assuntos
Antígenos de Histocompatibilidade Classe I/sangue , Peptídeos e Proteínas de Sinalização Intercelular/sangue , Leucemia Linfocítica Crônica de Células B/sangue , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Proteínas Ligadas por GPI , Humanos , Leucemia Linfocítica Crônica de Células B/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
12.
Leukemia ; 23(11): 2129-38, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19657361

RESUMO

Anaplastic large cell lymphoma (ALCL) is a main type of T-cell lymphomas and comprises three distinct entities: systemic anaplastic lymphoma kinase (ALK) positive, systemic ALK(-) and cutaneous ALK(-) ALCL (cALCL). Little is known about their pathogenesis and their cellular origin, and morphological and immunophenotypical overlap exists between ALK(-) ALCL and classical Hodgkin lymphoma (cHL). We conducted gene expression profiling of microdissected lymphoma cells of five ALK(+) and four ALK(-) systemic ALCL, seven cALCL and sixteen cHL, and of eight subsets of normal T and NK cells. The analysis supports a derivation of ALCL from activated T cells, but the lymphoma cells acquired a gene expression pattern hampering an assignment to a CD4(+), CD8(+) or CD30(+) T-cell origin. Indeed, ALCL display a down-modulation of many T-cell characteristic molecules. All ALCL types show significant expression of NFkappaB target genes and upregulation of genes involved in oncogenesis (e.g. EZH2). Surprisingly, few genes are differentially expressed between systemic and cALCL despite their different clinical behaviour, and between ALK(-) ALCL and cHL despite their different cellular origin. ALK(+) ALCL are characterized by expression of genes regulated by pathways constitutively activated by ALK. This study provides multiple novel insights into the molecular biology and pathogenesis of ALCL.


Assuntos
Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Doença de Hodgkin/genética , Linfoma Anaplásico de Células Grandes/genética , Adolescente , Adulto , Idoso , Quinase do Linfoma Anaplásico , Linhagem Celular , Feminino , Doença de Hodgkin/patologia , Humanos , Imuno-Histoquímica , Células Matadoras Naturais/citologia , Células Matadoras Naturais/fisiologia , Linfoma Anaplásico de Células Grandes/patologia , Masculino , Microdissecção , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Fenótipo , Proteínas Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T/citologia , Linfócitos T/fisiologia , Adulto Jovem
13.
Br J Haematol ; 142(2): 166-78, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18492111

RESUMO

Molecular genetic analysis adds important information for lymphoma biology and classification, but the latter is challenged by recent improvement of combined chemo-immunotherapy. In aggressive lymphoma, molecular profiling identifies risk groups with certain genetic background but still the International Prognostic Index (IPI) remains the most important clinically applicable predictor of outcome. In follicular lymphoma (FL), the importance of the meshwork of bystander cells becomes increasingly evident. As combined immuno-chemotherapy improved the prognosis of the patients, several clinical trials indicated that the FLIPI still efficiently discriminates patients at risk for transformation and relapse, although several mechanisms of transformation seem to exist. In mantle cell lymphoma it has been proven that pathogenesis and prognosis mainly depend on deregulation of the cell cycle. A reliable clinical risk score could be established.


Assuntos
Linfoma Folicular/patologia , Linfoma de Célula do Manto/patologia , Linfoma/patologia , Anticorpos Monoclonais/uso terapêutico , Ciclo Celular/genética , Humanos , Linfoma/genética , Linfoma/terapia , Linfoma Folicular/genética , Linfoma Folicular/terapia , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/terapia , Prognóstico , Fatores de Risco
14.
Leukemia ; 21(7): 1532-44, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17495977

RESUMO

The biologic and pathologic features of B-cell malignancies bearing a translocation t(14;19)(q32;q13) leading to a fusion of IGH and BCL3 are still poorly described. Herein we report the results of a comprehensive cytogenetic, fluorescence in situ hybridization (FISH), molecular and histopathological survey of a large series of B-cell malignancies with t(14;19) or variant translocations. A total of 56 B-cell malignancies with a FISH-proven BCL3 involvement were identified with the translocation partners being IGH (n=51), IGL (n=2), IGK (n=2) and a non-IG locus (n=1). Hierarchical clustering of chromosomal changes associated with the t(14;19) indicated the presence of two different groups of IG/BCL3-positive lymphatic neoplasias. The first group included 26 B-cell malignancies of various histologic subtypes containing a relatively high number of chromosomal changes and mostly mutated IgVH genes. This cluster displayed three cytogenetic branches, one with rearrangements in 7q, another with deletions in 17p and a third one with rearrangements in 1q and deletions in 6q and 13q. The second group included 19 cases, mostly diagnosed as B-cell chronic lymphocytic leukemia (B-CLL), and characterized by few additional chromosomal changes (e.g. trisomy 12) and unmutated IgVH genes. In conclusion, our study indicates that BCL3 translocations are not restricted to B-CLL but present in a heterogeneous group of B-cell malignancies.


Assuntos
Leucemia de Células B/genética , Linfoma de Células B/genética , Proteínas Proto-Oncogênicas/genética , Fatores de Transcrição/genética , Translocação Genética , Adulto , Idoso , Proteína 3 do Linfoma de Células B , Cromossomos Humanos Par 14 , Cromossomos Humanos Par 19 , Análise Citogenética , Feminino , Rearranjo Gênico , Genes de Imunoglobulinas , Histocitoquímica , Humanos , Hibridização in Situ Fluorescente , Leucemia de Células B/classificação , Leucemia de Células B/patologia , Linfoma de Células B/classificação , Linfoma de Células B/patologia , Masculino , Pessoa de Meia-Idade
15.
Leukemia ; 21(4): 780-7, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17375124

RESUMO

Mediastinal large B-cell (MBL) and classical Hodgkin lymphoma (HL) have several pathogenic mechanisms in common. As we recently observed aberrant tyrosine kinase (TK) activities in HL, we now analysed also MBL for such activities. Indeed, MBL and HL were the only B-cell lymphomas where elevated cellular phospho-tyrosine contents were typical features. Three TKs, JAK2, RON and TIE1, not expressed in normal B cells, were each expressed in about 30% of MBL cases, and 75% of cases expressed at least one of the TKs. Among the intracellular pathways frequently triggered by TKs, the PI3K/AKT pathway was activated in about 40% of MBLs and essential for survival of MBL cell lines, whereas the RAF/mitogen-activated protein kinase pathway seemed to be inhibited. No activating mutations were detected in the three TKs in MBL cell lines and primary cases. RON and TIE1 were each also expressed in about 35% and JAK2 in about 53% of HL cases. JAK2 genomic gains are frequent in MBL and HL but we observed no strict correlation of JAK2 genomic status with JAK2 protein expression. In conclusion, aberrant TK activities are a further shared pathogenic mechanism of MBL and HL and may be interesting targets for therapeutic intervention.


Assuntos
Regulação Neoplásica da Expressão Gênica , Doença de Hodgkin/genética , Linfoma de Células B/genética , Proteína Oncogênica v-akt/genética , Fosfatidilinositol 3-Quinases/genética , Proteínas Tirosina Quinases/genética , Ativação Enzimática , Regulação Enzimológica da Expressão Gênica , Doença de Hodgkin/classificação , Doença de Hodgkin/enzimologia , Humanos , Linfoma de Células B/classificação , Linfoma de Células B/enzimologia , Linfoma Difuso de Grandes Células B/enzimologia , Linfoma Difuso de Grandes Células B/genética , Proteína Oncogênica v-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo
16.
Leukemia ; 19(8): 1452-8, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15973455

RESUMO

Clonally related composite lymphomas of Hodgkin's lymphoma (HL) and Non-Hodgkin's lymphoma (NHL) represent models to study the multistep transformation process in tumorigenesis and the development of two distinct tumors from a shared precursor. We analyzed six such lymphomas for transforming events. The HLs were combined in two cases with follicular lymphoma (FL), and in one case each with B-cell chronic lymphocytic leukemia, splenic marginal zone lymphoma, mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL). In the HL/FL and HL/MCL combinations, BCL2/IGH and CCND1/IGH translocations, respectively, were detected in both the HL and NHL. No mutations were found in the tumor suppressor genes FAS, NFKBIA and ATM. The HL/DLBCL case harbored clonal replacement mutations of the TP53 gene on both alleles exclusively in the DLBCL. In conclusion, we present the first examples of molecularly verified IgH-associated translocations in HL, which also show that BCL2/IGH or CCND1/IGH translocations can represent early steps in the pathogenesis of composite HL/FL or HL/MCL. The restriction of the TP53 mutations to the DLBCL in the HL/DLBCL case exemplifies a late transforming event that presumably happened in the germinal center and affected the fate of a common lymphoma precursor cell towards development of a DLBCL.


Assuntos
Transformação Celular Neoplásica/genética , Genes Supressores de Tumor , Cadeias Pesadas de Imunoglobulinas/genética , Linfoma/patologia , Mutação , Translocação Genética , Transformação Celular Neoplásica/patologia , Células Clonais , Ciclina D1/genética , Genes bcl-2 , Doença de Hodgkin/patologia , Humanos , Linfoma/etiologia , Linfoma/genética , Linfoma não Hodgkin/patologia , Proteína Supressora de Tumor p53/genética
18.
Ann Oncol ; 13 Suppl 1: 11-8, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12078890

RESUMO

Significant progress has been made in recent years in our understanding of the cellular origin of Hodgkin and Reed-Sternberg (HRS) cells in Hodgkin's lymphoma (HL). It is now clear that in most instances HRS cells represent clonal populations of transformed germinal centre (GC) B cells. While the tumour cells in the lymphocyte predominant type of the disease resemble mutating and antigen-selected GC B cells, there is evidence that HRS cells in classical HL originate from pre-apoptotic GC B cells. HRS cells of the recently defined novel subtype lymphocyte-rich classical HL moleculary resemble HRS cells of the other types of classical HL, but there appear to be phenotypic differences. In rare cases, HRS cells derive from T cells. In contrast to previous speculations, cell fusion apparently does not play a role in the generation of the tumour clone. By gene expression profiling of HL cell lines, it became evident that HRS cells have lost most of the B cell-typical gene expression program, which may explain why these cells can persist without B cell receptor expression and which suggests that at least one of the transforming events involved in HL pathogenesis affects a master regulator of cell lineage identity.


Assuntos
Doença de Hodgkin/patologia , Animais , Linfócitos B/patologia , Células Clonais , Expressão Gênica , Rearranjo Gênico , Doença de Hodgkin/genética , Humanos , Células de Reed-Sternberg/patologia , Linfócitos T/patologia
19.
Leukemia ; 16(5): 937-9, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-11986957

RESUMO

The t(2;14)(p13;q32.3) involving the BCL11A and IGH genes is a rare but recurrent chromosomal aberration in B-cell malignancies. Hitherto, juxtaposition of BCL11A and IGH has only been described in B-cell chronic lymphocytic leukemia (B-CLL) and immunocytoma. As subgroups of B-CLL can be distinguished by the pattern of somatic mutation of immunoglobulin variable (V) genes we investigated four lymphomas with IGH/BCL11A involvement for IGH hypermutation. Clonal V(H) gene rearrangements were amplified; in all four cases, sequencing of the amplificates revealed the rearranged V(H) genes to lack somatic mutations. These results suggest that t(2;14)(p13;q32.3) is associated with a subset of B-CLL/immunocytoma characterized by non-mutated IG genes deriving from pre-germinal center B cells. As the translocations in both informative cases are targeted to the switch regions of the IGG2 gene, which is mainly used in T cell-independent immune responses, these translocations presumably occurred in activated B cells in the course of T cell-independent immune responses outside the germinal center.


Assuntos
Proteínas de Transporte , Cromossomos Humanos Par 14 , Cromossomos Humanos Par 2 , Cadeias Pesadas de Imunoglobulinas/genética , Leucemia Linfocítica Crônica de Células B/genética , Linfoma de Células B/genética , Mutação , Proteínas de Neoplasias/genética , Proteínas Nucleares , Translocação Genética , Genes de Imunoglobulinas , Humanos , Região de Troca de Imunoglobulinas , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/classificação , Leucemia Linfocítica Crônica de Células B/diagnóstico , Linfoma de Células B/diagnóstico , Proteínas Repressoras , Análise de Sequência de DNA
20.
Eur J Immunol ; 31(12): 3631-7, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11745383

RESUMO

Southern blot analyses of immunoglobulin light chain gene rearrangements in human leukemias and myelomas indicated that lambda loci in kappa-producing cells are largely unrearranged while kappa loci in lambda producers are often rearranged and inactivated by rearrangements of the kappa-deleting element (KDE). For a systematic analysis of the regulation of light chain rearrangements during early B cell development in normal human B cells also considering functionality of the rearrangements, we used FACS-sorted single naive kappa- and lambda-expressing B cells from peripheral blood of healthy humans. V(kappa)J(kappa) and V(lambda)J(lambda) joints and rearrangements involving the KDE were amplified simultaneously from single cells and sequenced. Whereas only 2 - 3 % of kappa-expressing cells carry V(lambda)J(lambda) joints, nearly all lambda-expressing cells have rearranged kappa loci and indeed carry V(kappa)J(kappa) joints. The V(kappa)J(kappa) joints in lambda-expressing cells exhibit preferential J(kappa)4 and J(kappa)5 over J(kappa)1 and J(kappa)2 usage compared to kappa-expressing cells. Thirty percent of the V(kappa)J(kappa) joints in lambda producers are rearranged in-frame. These data indicate extensive sequential V(kappa)-J(kappa) rearrangements and inactivation of functional V(kappa)J(kappa) joints in lambda-expressing cells, presumably before V(lambda)J(lambda) joining.


Assuntos
Linfócitos B/fisiologia , Rearranjo Gênico , Genes de Imunoglobulinas , Cadeias Leves de Imunoglobulina/genética , Mapeamento Cromossômico , Humanos , Região de Junção de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Cadeias kappa de Imunoglobulina/genética , Cadeias lambda de Imunoglobulina/genética
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