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1.
Hematol Oncol ; 36(1): 307-315, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28219109

RESUMO

BRAF p.V600E mutations are detected in greater than 50% of pediatric Langerhans cell histiocytosis (LCH) lesions. However, the use of mutation-specific BRAF V600E immunohistochemistry (IHC) as a surrogate for molecular testing in pediatric LCH is unknown. We tested the mutation-specific BRAF V600E monoclonal antibody (clone VE1) in formalin-fixed, paraffin-embedded LCH samples from 26 pediatric patients (14 males and 12 females, ages 7 mo-17 y) using allele-specific real-time polymerase chain reaction (PCR) with a limit of detection of 0.5% as the comparative gold standard. BRAF VE1 staining was scored for both intensity (0-3+) and percentage of immunoreactive tumor cells (0%-100%). BRAF VE1 immunoreactivity was determined using both lenient (≥1+, ≥1%) and stringent (≥2+, ≥10%) scoring criteria. Using lenient-scoring criteria, we found that the sensitivity and specificity of IHC compared with allele-specific real-time PCR were 100.0% and 18.2%, respectively. The poor specificity of lenient IHC analysis was attributable to weak, 1+ staining in both BRAF-mutated and wild-type LCH. Using stringent-scoring criteria, we found that specificity improved to 100.0% at the expense of sensitivity that decreased to 80.0%. Stringent scoring generated 3 false-negative results, but in all cases, neoplastic tissue comprised less than 5% of the stained section and/or the specimen was decalcified. In conclusion, highly sensitive molecular assays remain the gold standard for BRAF mutation analysis in LCH paraffin-embedded lesions. To avoid false-positive results, unequivocal VE1 staining of 2+ intensity in greater than or equal to 10% neoplastic histiocytes is required. However, negative VE1 results require additional studies to exclude false-negatives, and stringent-scoring criteria may not be optimal for scant or decalcified specimens.


Assuntos
Histiocitose de Células de Langerhans/enzimologia , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Imuno-Histoquímica , Lactente , Masculino
2.
Acta Derm Venereol ; 97(7): 838-842, 2017 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-28421232

RESUMO

Langerhans cell histiocytosis is a rare histiocytic disorder for which skin involvement and management are poorly described in adults. The aim of this retrospective monocentric study in a national reference centre is to describe the clinical characteristics, quality of life, BRAF mutation status and outcomes of skin involvement in adult patients with Langerhans cell histiocytosis. Twenty-five patients (14 females, mean age 47 years) were included, with a median follow-up of 33 months (range 4-420 months). Patients experienced poor dermatological quality of life despite low body surface involvement. BRAFV600 mutations were detected in 8 of the 18 patients analysed (45%). Eight patients had an associated malignancy. Several treatment options were used and consisted of surgery, topical steroids and carmustine, thalidomide, methotrexate, vinblastine and steroids and cladribine. This study highlights the need to evaluate quality of life and to screen for associated malignancy in adult patients with Langerhans cell histiocytosis.


Assuntos
Histiocitose de Células de Langerhans/genética , Histiocitose de Células de Langerhans/terapia , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Qualidade de Vida , Pele/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Mutacional de DNA , Feminino , França , Marcadores Genéticos , Predisposição Genética para Doença , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , Sistema de Registros , Estudos Retrospectivos , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
3.
Blood ; 128(21): 2533-2537, 2016 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-27729324

RESUMO

Langerhans cell histiocytosis (LCH) is characterized by inflammatory lesions containing pathologic CD207+ dendritic cells with constitutively activated ERK. Mutually exclusive somatic mutations in MAPK pathway genes have been identified in ∼75% of LCH cases, including recurrent BRAF-V600E and MAP2K1 mutations. To elucidate mechanisms of ERK activation in the remaining 25% of patients, we performed whole-exome sequencing (WES, n = 6), targeted BRAF sequencing (n = 19), and/or whole-transcriptome sequencing (RNA-seq, n = 6) on 24 LCH patient samples lacking BRAF-V600E or MAP2K1 mutations. WES and BRAF sequencing identified in-frame BRAF deletions in the ß3-αC loop in 6 lesions. RNA-seq revealed one case with an in-frame FAM73A-BRAF fusion lacking the BRAF autoinhibitory regulatory domain but retaining an intact kinase domain. High levels of phospho-ERK were detected in vitro in cells overexpressing either BRAF fusion or deletion constructs and ex vivo in CD207+ cells from lesions. ERK activation was resistant to BRAF-V600E inhibition, but responsive to both a second-generation BRAF inhibitor and a MEK inhibitor. These results support an emerging model of universal ERK-activating genetic alterations driving pathogenesis in LCH. A personalized approach in which patient-specific alterations are identified may be necessary to maximize benefit from targeted therapies for patients with LCH.


Assuntos
Histiocitose de Células de Langerhans/genética , Mutação , Proteínas de Fusão Oncogênica/genética , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Ativação Enzimática/genética , Feminino , Histiocitose de Células de Langerhans/enzimologia , Humanos , Lactente , Masculino , Proteínas de Fusão Oncogênica/metabolismo , Domínios Proteicos , Proteínas Proto-Oncogênicas B-raf/metabolismo
4.
Diagn Pathol ; 11(1): 100, 2016 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-27760550

RESUMO

BACKGROUND: Isolated hypothalamic-pituitary Langerhans cell histiocytosis (HPLCH) is very rare. We investigated the clinicopathological characteristics, endocrine function changes, BRAFV600E mutations and treatments of isolated HPLCH. METHODS: We identified seven patients with isolated HPLCH by reviewing the clinical and pathological files in our hospital from 2007 to 2015. The clinical characteristics of the seven patients were retrospectively reviewed, especially the endocrine function changes. Immunostaining and mutation profiling of BRAFV600E were performed. RESULTS: The seven HPLCH patients included three men and four women, aged 9-47 years. All patients presented with symptoms of central diabetes insipidus (CDI), and four displayed anterior pituitary hypofunction as well. Magnetic resonance imaging showed hypothalamic-pituitary axis involvement in all patients. There was no evidence for the involvement of other organs in all seven patients. Langerhans cell histiocytosis was confirmed by neuroendoscopic procedures, and immunohistochemical staining showed that all cases (7/7) were positive for CD68, CD1a, Langerin, and S-100. The BRAFV600E mutation was detected in three of the six cases (3/6). Six patients had follow-up information; all received desmopressin acetate and high-dose corticosteroid therapy, and two patients received radiotherapy. CONCLUSIONS: Our study indicated that all patients with isolated HPLCH had CDI as the earliest symptom, and more than half of the patients had anterior pituitary deficiencies. The BRAFV600E mutation is a common genetic change in HPLCH patients. Treatment of HPLCH patients is difficult, and the progressive loss of endocrine function is irreversible in most cases.


Assuntos
Histiocitose de Células de Langerhans/genética , Doenças Hipotalâmicas/genética , Sistema Hipotálamo-Hipofisário/fisiopatologia , Mutação , Doenças da Hipófise/genética , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Adulto , Criança , Análise Mutacional de DNA , Diabetes Insípido Neurogênico/enzimologia , Diabetes Insípido Neurogênico/genética , Diabetes Insípido Neurogênico/fisiopatologia , Feminino , Predisposição Genética para Doença , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/fisiopatologia , Histiocitose de Células de Langerhans/terapia , Humanos , Doenças Hipotalâmicas/enzimologia , Doenças Hipotalâmicas/fisiopatologia , Doenças Hipotalâmicas/terapia , Sistema Hipotálamo-Hipofisário/metabolismo , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Fenótipo , Doenças da Hipófise/enzimologia , Doenças da Hipófise/fisiopatologia , Doenças da Hipófise/terapia , Adeno-Hipófise/metabolismo , Adeno-Hipófise/fisiopatologia , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
5.
J Clin Oncol ; 34(25): 3023-30, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27382093

RESUMO

PURPOSE: Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia with a broad spectrum of clinical manifestations and outcomes in children. The somatic BRAF(V600E) mutation occurs frequently, but clinical significance remains to be determined. PATIENTS AND METHODS: BRAF(V600E) mutation was investigated in a French LCH cohort. We analyzed associations between mutation status and clinical presentation, extent of disease, reactivation rate, response to therapy, and long-term permanent sequelae. RESULTS: Among 315 patients with successfully determined BRAF status, 173 (54.6%) carried a BRAF(V600E) mutation. Patients with BRAF(V600E) manifested more severe disease than did those with wild-type BRAF. Patients with BRAF(V600E) comprised 87.8% of patients (43 of 49) with multisystem LCH with risk organ involvement (liver, spleen, hematology), 68.6% of patients (35 of 51) with multisystem LCH without risk organ involvement, 43.9% of patients (86 of 196) with single-system LCH, and 42.1% of patients (8 of 19) with lung-involved LCH (P < .001). BRAF(V600E) mutation was also associated with organ involvement that could lead to permanent, irreversible damage, such as neurologic (75%) and pituitary (72.9%) injuries. Compared with patients with wild-type BRAF, patients with BRAF(V600E) more commonly displayed resistance to combined vinblastine and corticosteroid therapy (21.9% v 3.3%; P = .001), showed a higher reactivation rate (5-year reactivation rate, 42.8% v 28.1%; P = .006), and had more permanent, long-term consequences from disease or treatment (27.9% v 12.6%; P = .001). CONCLUSION: In children with LCH, BRAF(V600E) mutation was associated with high-risk features, permanent injury, and poor short-term response to chemotherapy. Further population-based studies should be undertaken to confirm our observations and to assess the impact of BRAF inhibitors for this subgroup of patients who may benefit from targeted therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Histiocitose de Células de Langerhans/tratamento farmacológico , Histiocitose de Células de Langerhans/genética , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Corticosteroides/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Criança , Pré-Escolar , Estudos de Coortes , Resistencia a Medicamentos Antineoplásicos , Feminino , França/epidemiologia , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/epidemiologia , Humanos , Lactente , Recém-Nascido , Masculino , Terapia de Alvo Molecular , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Sistema de Registros , Vimblastina/administração & dosagem
6.
Diagn Pathol ; 11: 39, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27094161

RESUMO

BACKGROUND: BRAF (V-raf murine sarcoma viral oncogene homolog B1) is a serine-threonine protein kinase involved in cell survival, proliferation, and differentiation. The most common missense mutation of BRAF (mainly V600E) contributes to the incidence of various cancers, including Langerhans cell histiocytosis (LCH). BRAF inhibitors molecularly targeting the V600E mutation have been developed to counteract the effect of the mutation. To ensure the administration of effective pharmacotherapy, it is therefore imperative to develop an effective assay to screen LCH patients for the V600E mutation. However, tumor tissues of LCH typically contain many inflammatory cells which make a correct judgement of the mutation status difficult in the DNA sequence analysis. RESULTS: In this study, we present a new, highly sensitive analyzing method combining PCR, restriction enzyme digestion, and a sequencing assay using DNA extracted from formalin-fixed paraffin-embedded (FFPE) tissue specimens. TspRI is a restriction enzyme that cleaves the sequence encompassing the wild-type BRAF codon 600 into two fragments, which cannot be used as a template for subsequent BRAF PCR amplification. We therefore evaluated the sensitivity of BRAF V600 mutation detection by amplifying the primary PCR product digested with TspRI and sequencing the secondary PCR products. The V600E mutation was detected in FFPE tissue samples from 32 LCH patients; our assay was able to identify mutations in four samples that gave inconclusive results, and ten that were negative, according to standard PCR and sequencing. CONCLUSIONS: We presented a new and highly sensitive method to detect BRAF V600 mutations. This screening method is expected to play an important role to select the most effective therapies.


Assuntos
Análise Mutacional de DNA/métodos , Histiocitose de Células de Langerhans/genética , Mutação , Reação em Cadeia da Polimerase , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Antígenos CD1/análise , Sequência de Bases , Estudos de Casos e Controles , Linhagem Celular , Criança , Pré-Escolar , Feminino , Fixadores , Formaldeído , Marcadores Genéticos , Predisposição Genética para Doença , Histiocitose de Células de Langerhans/diagnóstico , Histiocitose de Células de Langerhans/enzimologia , Humanos , Imuno-Histoquímica , Lactente , Recém-Nascido , Masculino , Dados de Sequência Molecular , Inclusão em Parafina , Fenótipo , Valor Preditivo dos Testes , Prognóstico , Reprodutibilidade dos Testes , Fixação de Tecidos
7.
Hum Pathol ; 52: 61-7, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26980021

RESUMO

Langerhans cell histiocytosis (LCH) is a proliferation of Langerhans cells, often associated with lymphocytes, eosinophils, macrophages, and giant cells. BRAF mutations, usually V600E, have been reported in 40%-70% of cases, and recently, MAP2K1 mutations have been reported in BRAF-negative cases. We assessed 50 cases of LCH for BRAF mutations and assessed a subset of cases for MAP2K1 mutations. The study group included 28 men and 22 women (median age, 36.5 years; range, 1-78 years). BRAF V600E mutation was detected in 8 (16%) cases including 3 (30%) skin, 2 (11%) bone, 1 (50%) colon, 1 (20%) lung, and 1 (33%) extradural, intracranial mass. MAP2K1 mutations were detected in 6 of 13 (46%) BRAF-negative cases including 2 (100%) lymph node, 2 (50%) bone, 1 (25%) skin, and 1 (100%) orbit. Patients with BRAF mutation were younger than patients with wild-type BRAF (median age, 28 versus 38 years; P = .026). The median age of MAP2K1-mutated patients was 34.5 years, similar to patients without MAP2K1 mutation (41 years; P = .368). In agreement with 2 recent studies, we showed a high frequency of MAP2K1 mutations in BRAF-negative LCH cases. Unlike other studies, the overall frequency of BRAF mutation in this cohort is substantially lower than what has been reported in pediatric patients, perhaps because most patients in this study were adults. Moreover, we showed a high concordance between mutational and immunohistochemical analysis for BRAF mutation. There was no statistically significant association between BRAF or MAP2K1 mutation and anatomic site, unifocal versus multifocal presentation, or clinical outcome.


Assuntos
Histiocitose de Células de Langerhans/genética , MAP Quinase Quinase 1/genética , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Adulto , Idoso , Biópsia , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Marcadores Genéticos , Predisposição Genética para Doença , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/patologia , Humanos , Imuno-Histoquímica , Lactente , Masculino , Pessoa de Meia-Idade , Fenótipo , Adulto Jovem
8.
Oncology (Williston Park) ; 30(2): 122-32, 139, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26888790

RESUMO

Langerhans cell histiocytosis is a disorder characterized by lesions that include CD207+ dendritic cells along with an inflammatory infiltrate. Langerhans cell histiocytosis has a highly variable clinical presentation, ranging from a single lesion to potentially fatal disseminated disease. The uncertainty as to whether Langerhans cell histiocytosis is a reactive or a neoplastic disease has resulted in a long-standing debate on this question, and the limited understanding of the pathogenesis of the disease has impeded clinical improvement for patients. The current standard of care for multisystem Langerhans cell histiocytosis, empirically derived chemotherapy with vinblastine and prednisone, cures fewer than 50% of patients, and optimal therapies for relapse and neurodegenerative disease remain uncertain. Recent research advances support a model in which Langerhans cell histiocytosis arises due to pathologic activation of the mitogen-activated protein kinase (MAPK) pathway in myeloid precursors. Redefinition of Langerhans cell histiocytosis as a myeloid neoplastic disorder driven by hyperactive ERK supports the potential of chemotherapy with efficacy against immature myeloid cells, as well as mutation-specific targeted therapy.


Assuntos
Histiocitose de Células de Langerhans , Células de Langerhans , Animais , Antígenos CD/imunologia , Antígenos CD/metabolismo , Progressão da Doença , Ativação Enzimática , Histiocitose de Células de Langerhans/diagnóstico , Histiocitose de Células de Langerhans/tratamento farmacológico , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/imunologia , Humanos , Células de Langerhans/efeitos dos fármacos , Células de Langerhans/enzimologia , Células de Langerhans/imunologia , Células de Langerhans/patologia , Lectinas Tipo C/imunologia , Lectinas Tipo C/metabolismo , Lectinas de Ligação a Manose/imunologia , Lectinas de Ligação a Manose/metabolismo , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Terapia de Alvo Molecular , Prednisona/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Transdução de Sinais , Resultado do Tratamento , Vimblastina/uso terapêutico
9.
Cancer Discov ; 6(2): 154-65, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26566875

RESUMO

UNLABELLED: Histiocytic neoplasms are clonal, hematopoietic disorders characterized by an accumulation of abnormal, monocyte-derived dendritic cells or macrophages in Langerhans cell histiocytosis (LCH) and non-Langerhans cell histiocytosis (non-LCH), respectively. The discovery of BRAF(V600E) mutations in approximately 50% of these patients provided the first molecular therapeutic target in histiocytosis. However, recurrent driving mutations in the majority of patients with BRAF(V600E)-wild-type non-LCH are unknown, and recurrent cooperating mutations in non-MAP kinase pathways are undefined for the histiocytic neoplasms. Through combined whole-exome and transcriptome sequencing, we identified recurrent kinase fusions involving BRAF, ALK, and NTRK1, as well as recurrent, activating MAP2K1 and ARAF mutations in patients with BRAF(V600E)-wild-type non-LCH. In addition to MAP kinase pathway lesions, recurrently altered genes involving diverse cellular pathways were identified. Treatment of patients with MAP2K1- and ARAF-mutated non-LCH using MEK and RAF inhibitors, respectively, resulted in clinical efficacy, demonstrating the importance of detecting and targeting diverse kinase alterations in these disorders. SIGNIFICANCE: We provide the first description of kinase fusions in systemic histiocytic neoplasms and activating ARAF and MAP2K1 mutations in non-Langerhans histiocytic neoplasms. Refractory patients with MAP2K1- and ARAF-mutant histiocytoses had clinical responses to MEK inhibition and sorafenib, respectively, highlighting the importance of comprehensive genomic analysis of these disorders.


Assuntos
Perfilação da Expressão Gênica/métodos , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células não Langerhans/enzimologia , Mutação , Análise de Sequência de DNA/métodos , Quinase do Linfoma Anaplásico , Histiocitose de Células de Langerhans/tratamento farmacológico , Histiocitose de Células de Langerhans/genética , Histiocitose de Células não Langerhans/tratamento farmacológico , Histiocitose de Células não Langerhans/genética , Humanos , MAP Quinase Quinase 1/genética , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/genética , Receptores Proteína Tirosina Quinases/genética , Receptor trkA/genética
11.
Oncotarget ; 6(23): 19819-25, 2015 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-26110571

RESUMO

The histiocytoses are rare tumors characterized by the primary accumulation and tissue infiltration of histiocytes and dendritic cells. Identification of the activating BRAFV600E mutation in Erdheim-Chester disease (ECD) and Langerhans cell histiocytosis (LCH) cases provided the basis for the treatment with BRAF and/or MEK inhibitors, but additional treatment options are needed. Twenty-four cases of neoplastic histiocytic diseases [11 extrapulmonary LCH, 4 ECD, 4 extranodal Rosai-Dorfman disease (RDD), 3 follicular dendritic cell sarcoma (FDCS), 1 histiocytic sarcoma (HS) and 1 blastic plasmacytoid dendritic cell neoplasm (BPDCN)] were analyzed using immunohistochemical and mutational analysis in search of biomarkers for targeted therapy. BRAF V600E mutations were detected in 4/11 LCH and 4/4 ECD cases. A pathogenic PTEN gene mutation and loss of PTEN protein expression were identified in the case of HS. Increased expression of PD-L1 (≥2+/≥5%) was seen in 3/4 ECD, 7/8 LCH, 3/3 FDCS and 1/1 HS, with overall 81% concordance between 2 antibodies used in the study (SP142 vs. MAB1561 clone). These results show for the first time significant expression of the PD-L1 immune checkpoint protein in these disorders, which may provide rationale for addition of immune check-point inhibitors in treatment of disseminated and/or refractory histiocytoses.


Assuntos
Antígeno B7-H1/análise , Sarcoma de Células Dendríticas Foliculares/metabolismo , Células Dendríticas/química , Doença de Erdheim-Chester/metabolismo , Histiócitos/química , Sarcoma Histiocítico/metabolismo , Histiocitose de Células de Langerhans/metabolismo , Histiocitose Sinusal/metabolismo , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Análise Mutacional de DNA , Sarcoma de Células Dendríticas Foliculares/enzimologia , Sarcoma de Células Dendríticas Foliculares/genética , Sarcoma de Células Dendríticas Foliculares/patologia , Células Dendríticas/enzimologia , Doença de Erdheim-Chester/enzimologia , Doença de Erdheim-Chester/genética , Doença de Erdheim-Chester/patologia , Feminino , Marcadores Genéticos , Histiócitos/enzimologia , Histiócitos/patologia , Sarcoma Histiocítico/enzimologia , Sarcoma Histiocítico/genética , Sarcoma Histiocítico/patologia , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/genética , Histiocitose de Células de Langerhans/patologia , Histiocitose Sinusal/enzimologia , Histiocitose Sinusal/genética , Histiocitose Sinusal/patologia , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , PTEN Fosfo-Hidrolase/análise , PTEN Fosfo-Hidrolase/genética , Adulto Jovem
12.
Ann Diagn Pathol ; 19(3): 113-6, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25787243

RESUMO

BRAF V600E mutations have been reported in several histiocytic and dendritic cell neoplasms. In this case series, we report BRAF V600E-positive histiocytic and dendritic cell neoplasms in association with lymphomas and lymphoid proliferations. This is a review of cases with immunohistochemistry for BRAF V600E, with additional immunohistochemistry to categorize tumors. We report the first case of BRAF V600E-positive indeterminate cell tumor in association with angioimmunoblastic T-cell lymphoma. We also report a case of BRAF V600E-positive interdigitating dendritic cell sarcoma in a patient with positive B-cell polymerase chain reaction. It is unclear if these neoplasms developed as transdifferentiation of lymphoid neoplasms or if they developed independently. These cases illustrate the expanding spectrum of BRAF V600E-positive histiocytic and dendritic cell tumors and suggest that attention should be paid to lymphomas for possible coincident presentation of these disorders.


Assuntos
Sarcoma de Células Dendríticas Interdigitantes/enzimologia , Proteínas Proto-Oncogênicas B-raf/metabolismo , Linfócitos B/enzimologia , Linfócitos B/patologia , Transdiferenciação Celular/fisiologia , Sarcoma de Células Dendríticas Interdigitantes/genética , Sarcoma de Células Dendríticas Interdigitantes/patologia , Feminino , Citometria de Fluxo , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/genética , Histiocitose de Células de Langerhans/patologia , Humanos , Imuno-Histoquímica , Linfoma de Células T/enzimologia , Linfoma de Células T/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Reação em Cadeia da Polimerase
13.
Blood ; 123(20): 3063-5, 2014 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-24832939

RESUMO

In this issue of Blood, Nelson et al describe a novel somatic ARAF mutation in a child with Langerhans cell histiocytosis (LCH) and demonstrate that the encoded protein has strong gain-of-function properties. Importantly, this mutant A-Raf molecule is sensitive to inhibition by vemurafenib, a potent and selective Raf kinase inhibitor that is Food and Drug Administration (FDA)-approved for the treatment of advanced melanoma. This work thus identifies a new driver mutation in LCH that is potentially actionable in the clinic.


Assuntos
Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/genética , Mutação , Proteínas Proto-Oncogênicas A-raf/genética , Animais , Humanos
14.
Pediatr Blood Cancer ; 61(10): 1883-5, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24737657

RESUMO

Heparanase is an endo-beta D-glucuronidase capable of cleaving heparan sulfate side chains, yielding heparan sulfate fragments. Heparanase activity has been correlated with the metastatic potential of tumor-derived cells, angiogenesis, autoimmunity and inflammation. We performed a study of heparanase expression in specimens obtained from patients with Langerhans cell histiocytosis (LCH). Paraffin embedded slides from 25 patients were studied by immunohistochemistry for heparanase. Most patients had positive staining for heparanase (21/25). There was no positive association with severity of disease and other clinical characteristics. Further studies are required to clarify the role of heparanase in the pathogenesis of LCH.


Assuntos
Glucuronidase/biossíntese , Histiocitose de Células de Langerhans/enzimologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Glucuronidase/análise , Histiocitose de Células de Langerhans/patologia , Humanos , Imuno-Histoquímica , Lactente , Masculino , Adulto Jovem
15.
Blood ; 123(20): 3152-5, 2014 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-24652991

RESUMO

The extracellular signal-regulated kinase (ERK) signaling pathway is activated in Langerhans cell histiocytosis (LCH) histiocytes, but only 60% of cases carry somatic activating mutations of BRAF. To identify other genetic causes of ERK pathway activation, we performed whole exome sequencing on purified LCH cells in 3 cases. One patient with wild-type BRAF alleles in his histiocytes had compound mutations in the kinase domain of ARAF. Unlike wild-type ARAF, this mutant was a highly active mitogen-activated protein kinase kinase in vitro and was capable of transforming mouse embryo fibroblasts. Mutant ARAF activity was inhibited by vemurafenib, a BRAF inhibitor, indicating the importance of fully evaluating ERK pathway abnormalities in selecting LCH patients for targeted inhibitor therapy.


Assuntos
Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/genética , Mutação , Proteínas Proto-Oncogênicas A-raf/genética , Animais , Células 3T3 BALB , Ativação Enzimática , Histiocitose de Células de Langerhans/patologia , Humanos , Células de Langerhans/enzimologia , Células de Langerhans/metabolismo , Células de Langerhans/patologia , Sistema de Sinalização das MAP Quinases , Camundongos , Proteínas Proto-Oncogênicas B-raf/genética
16.
PLoS One ; 7(4): e33891, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22506009

RESUMO

BACKGROUND: Langerhans cell histiocytosis (LCH) features inflammatory granuloma characterised by the presence of CD1a+ dendritic cells or 'LCH cells'. Badalian-Very et al. recently reported the presence of a canonical (V600E)B-RAF mutation in 57% of paraffin-embedded biopsies from LCH granuloma. Here we confirm their findings and report the identification of two novel B-RAF mutations detected in LCH patients. METHODS AND RESULTS: Mutations of B-RAF were observed in granuloma samples from 11 out of 16 patients using 'next generation' pyrosequencing. In 9 cases the mutation identified was (V600E)B-RAF. In 2 cases novel polymorphisms were identified. A somatic (600DLAT)B-RAF insertion mimicked the structural and functional consequences of the (V600E)B-RAF mutant. It destabilized the inactive conformation of the B-RAF kinase and resulted in increased ERK activation in 293 T cells. The (600DLAT)B-RAF and (V600E)B-RAF mutations were found enriched in DNA and mRNA from the CD1a+ fraction of granuloma. They were absent from the blood and monocytes of 58 LCH patients, with a lower threshold of sequencing sensitivity of 1%-2% relative mutation abundance. A novel germ line (T599A)B-RAF mutant allele was detected in one patient, at a relative mutation abundance close to 50% in the LCH granuloma, blood monocytes and lymphocytes. However, (T599A)B-RAF did not destabilize the inactive conformation of the B-RAF kinase, and did not induce increased ERK phosphorylation or C-RAF transactivation. CONCLUSIONS: Our data confirmed presence of the (V600E)B-RAF mutation in LCH granuloma of some patients, and identify two novel B-RAF mutations. They indicate that (V600E)B-RAF and (600DLAT)B-RAF mutations are somatic mutants enriched in LCH CD1a(+) cells and absent from the patient blood. Further studies are needed to assess the functional consequences of the germ-line (T599A)B-RAF allele.


Assuntos
Granuloma/genética , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/genética , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Alelos , Sequência de Aminoácidos , Criança , Pré-Escolar , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Predisposição Genética para Doença , Granuloma/metabolismo , Células HEK293 , Histiocitose de Células de Langerhans/metabolismo , Humanos , Lactente , Linfócitos/metabolismo , Masculino , Dados de Sequência Molecular , Monócitos/metabolismo , Fosforilação/genética , Polimorfismo Genético , Proteínas Proto-Oncogênicas B-raf/metabolismo , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas c-raf/metabolismo , Homologia de Sequência de Aminoácidos , Ativação Transcricional , Adulto Jovem
17.
Virchows Arch ; 459(2): 227-34, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21604205

RESUMO

Langerhans cell histiocytosis (LCH) is a proliferative disorder of Langerhans cell (LC)-like CD1a-positive cell (LCH cell) with unknown causes. LCH consists of two subtypes: single-system LCH (LCH-SS) with favorable prognosis and multisystem LCH (LCH-MS) with poor prognosis. LCH has been indicated as a neoplastic disorder from monoclonal characteristics of LCH cells. This study aimed to investigate an expression of tyrosine phosphatase SHP-1 in LCH, since its expression levels were variously reported in many tumors, overexpression in ovarian cancers (a candidate oncoprotein), and downregulation by methylation in gastric cancers, prostate cancers, malignant lymphomas, and leukemias (a putative tumor suppressor). By immunohistochemistry (IHC), the SHP-1 expression in LCs and LCH cells was compared in LCH (two subtypes: LCH-SS = 21, LCH-MS = 12), dermatopathic lymphadenopathy (DLA) (n = 9) and normal epidermal LCs (n = 3) near LCH lesion. IHC results were analyzed semiquantitatively using a Photoshop software. The mean intensity score (IS) of DLA, LCH-SS, LCH-MS, and LCs were 47, 100, 139, and 167 (in arbitrary unit), respectively. The IS had significant differences among LCH-SS, LCH-MS, and DLA (p < 0.01). SHP-1 is expressed significantly higher in LCH-MS than in LCH-SS. SHP-1 can be a progression marker of LCH. SHP-1 is also useful for differential diagnosis between LCH in lymph nodes and DLA.


Assuntos
Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/biossíntese , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/análise , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Imunofluorescência , Humanos , Interpretação de Imagem Assistida por Computador , Imuno-Histoquímica , Lactente , Recém-Nascido , Linfonodos/patologia , Doenças Linfáticas/diagnóstico , Masculino , Pessoa de Meia-Idade , Adulto Jovem
18.
Pathol Res Pract ; 204(5): 315-22, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18337020

RESUMO

Pulmonary Langerhans' cell histiocytosis (PLCH) is a disease characterized by the occurrence of complex fibro-cellular interstitial lesions dominated by Langerhans' cells (LC), which occurs predominantly in young adult smokers. We undertook this retrospective study to better define the lymphohistiocytic cell populations in PLCH in order to obtain a greater insight into its pathogenesis. Formalin-fixed, paraffin-embedded, surgically excised, archival lung tissue from seven patients (two males, five females; average age 34.9 years) was immunostained with a panel of antibodies for lymphohistiocytic markers: CD1a, CD3, CD4, CD8, CD15, CD20, CD56, TIA-1, CD68-PGM1, Mac387, and mast cell tryptase. Double immunolabeling was performed with CD1a/Mac387. Leder cytochemical stain for chloroacetate esterase was also performed. A moderate number of lymphocytes, predominantly T lymphocytes, were scattered diffusely within the lesions. The mean CD4/CD8 ratio was 0.1/1. The CD3/CD8 ratio (1.18/1) substantiated the CD4/CD8 ratio. The CD8 subset was CD56-negative and TIA-1-positive, indicating a cytotoxic T lymphocyte phenotype. CD68-PGM1 was strongly positive in alveolar macrophages (AM) and weakly stained LC. Mac387, a marker of activated macrophages, weakly stained AM, while highlighting other interstitial cells. These interstitial cells appeared not to be LC (substantiated by CD1a/Mac387 dual labeling) or CD68-PGM-1-positive macrophages. Having excluded mast cells (positive with mast cell tryptase) and neutrophils (positive with CD15 and Leder stains), there appeared to be a residual population of non-Langerhans cell monocytoid cells (NLMC), which were Mac 387+, CD68-PGM1-, Mast cell tryptase-, CD15-, and CD1a-. Our results showed a predominance of CD8+, TIA-1+ cytotoxic T lymphocytes among the lymphocyte subsets which appear to interact with LC and AM in PLCH lesions. A small sub-population of NLMC was also present. Further studies are required to better define and to evaluate the role of cytotoxic T cells and NLMC in the pathogenesis of PLCH.


Assuntos
Histiocitose de Células de Langerhans/patologia , Pulmão/patologia , Subpopulações de Linfócitos/patologia , Monócitos/patologia , Linfócitos T Citotóxicos/patologia , Adulto , Antígenos CD/análise , Hidrolases de Éster Carboxílico/análise , Feminino , Histiocitose de Células de Langerhans/enzimologia , Histiocitose de Células de Langerhans/imunologia , Humanos , Imuno-Histoquímica , Células de Langerhans/patologia , Pulmão/enzimologia , Pulmão/imunologia , Subpopulações de Linfócitos/enzimologia , Subpopulações de Linfócitos/imunologia , Macrófagos Alveolares/patologia , Masculino , Mastócitos/patologia , Monócitos/enzimologia , Monócitos/imunologia , Neutrófilos/patologia , Estudos Retrospectivos , Linfócitos T Citotóxicos/enzimologia , Linfócitos T Citotóxicos/imunologia , Triptases/análise
19.
J Pathol ; 212(2): 188-97, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17447723

RESUMO

Langerhans cell histiocytosis (LCH) is a disease characterized by an uncontrolled clonal proliferation of Langerhans cells, whose aetiology is still unclear. The clonal nature of LCH could support the hypothesis that it is a neoplastic disease with unlimited growth potential. One requirement for unlimited proliferation is the maintenance of telomere length. In a group of 70 patients, we set out to investigate whether a telomere maintenance mechanism is indeed active in LCH cells. This work showed that LCH cells from all restricted skin LCH lesions (6/6) expressed telomerase as assessed by human telomere reverse transcriptase (hTERT) immunohistochemistry, whereas LCH cells from the majority of the bone lesions analysed did not express hTERT (26/34). Interestingly, in contrast to the solitary bone lesions, LCH cells from lesions of multi-system patients always expressed telomerase (11/11), regardless of the lesional site. In situ telomeric repeat amplification protocol (TRAP) assays performed on different lesional sites showed that this telomerase was active. In addition, the telomere length of LCH cells from a hTERT-positive skin multi-system lesion was long and homogeneous when compared to that in the LCH cells from hTERT-negative bone single-system LCH lesions, which was heterogeneous in length. No evidence for an alternative lengthening of telomeres mechanism was found in hTERT-negative lesions. The difference in telomerase expression and telomere length at the different lesional sites and in biopsies from patients with solitary versus multi-system disease appears to reflect the diverse clinical presentation and course of this disease. The results from this study have important implications for understanding the nature of this disease.


Assuntos
Antígenos CD1/imunologia , Histiocitose de Células de Langerhans/enzimologia , Telomerase/análise , Osso e Ossos/imunologia , Osso e Ossos/patologia , Criança , Células Gigantes/metabolismo , Células Gigantes/patologia , Histiocitose de Células de Langerhans/imunologia , Humanos , Imuno-Histoquímica/métodos , Células de Langerhans/enzimologia , Células de Langerhans/imunologia , Pele/imunologia , Pele/patologia , Telômero/patologia
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