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1.
Am J Physiol Endocrinol Metab ; 321(4): E543-E550, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34459217

RESUMO

Sleep apnea is a common sleep disorder characterized by periodic breathing cessation and intermittent hypoxia (IH). Although previous studies have demonstrated that IH alone can influence metabolic outcomes such as body weight, it remains unclear how the timing of IH can specifically affect these outcomes. Here, we examine how pairing 10-h periods of IH to either the animals' resting phase (e.g., IH during the day) or active phase (e.g., IH during the night) differentially affects body weight, macronutrient selection, energy expenditure, respiratory exchange rate, and glucose tolerance. We find that in contrast to mice exposed to IH during the night, mice exposed to IH during the day preferentially decrease their carbohydrate intake and switch to fat metabolism. Moreover, when the IH stimulus was removed, mice that had been exposed to day IH continued to eat a minimal amount of carbohydrates and consumed a higher percentage of kilocalorie from fat for at least 5 days. These data demonstrate that food choice and substrate utilization are secondary to the timing of IH but not IH itself. Taken together, these data have key clinical implications for individuals with sleep apnea and particularly those who are also experiencing circadian disruption such as night-shift workers.NEW & NOTEWORTHY Pairing repeated hypoxic episodes to a mouse's resting phase during the day preferentially decreases carbohydrate intake and results in a switch to metabolic fat oxidation. These data indicate that the timing of intermittent hypoxia should be considered when calculating sleep apnea's effects on metabolic outcomes.


Assuntos
Distribuição da Gordura Corporal , Ingestão de Alimentos , Metabolismo Energético , Hipóxia/fisiopatologia , Resistência à Insulina , Metabolismo dos Lipídeos , Animais , Peso Corporal , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Tempo
2.
Blood ; 123(18): 2838-42, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24553178

RESUMO

Although hyperactivation of the Ras-Erk signaling pathway is known to underlie the pathogenesis of juvenile myelomonocytic leukemia (JMML), a fatal childhood disease, the PI3K-Akt signaling pathway is also dysregulated in this disease. Using genetic models, we demonstrate that inactivation of phosphatidylinositol-3-kinase (PI3K) catalytic subunit p110δ, but not PI3K p110α, corrects gain-of-function (GOF) Shp2-induced granulocyte macrophage-colony-stimulating factor (GM-CSF) hypersensitivity, Akt and Erk hyperactivation, and skewed hematopoietic progenitor distribution. Likewise, potent p110δ-specific inhibitors curtail the proliferation of GOF Shp2-expressing hematopoietic cells and cooperate with mitogen-activated or extracellular signal-regulated protein kinase kinase (MEK) inhibition to reduce proliferation further and maximally block Erk and Akt activation. Furthermore, the PI3K p110δ-specific inhibitor, idelalisib, also demonstrates activity against primary leukemia cells from individuals with JMML. These findings suggest that selective inhibition of the PI3K catalytic subunit p110δ could provide an innovative approach for treatment of JMML, with the potential for limiting toxicity resulting from the hematopoietic-restricted expression of p110δ.


Assuntos
Classe Ia de Fosfatidilinositol 3-Quinase/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Leucemia Mielomonocítica Juvenil/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Animais , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Proliferação de Células/efeitos dos fármacos , Classe Ia de Fosfatidilinositol 3-Quinase/genética , Modelos Animais de Doenças , Ativação Enzimática/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Leucemia Mielomonocítica Juvenil/genética , Camundongos , Camundongos Knockout , Inibidores de Proteínas Quinases/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos
4.
Psychiatry Res Commun ; 3(2): 100109, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36942154

RESUMO

The COVID-19 pandemic has presented many stressors for parents. This study was conducted to examine treatment preferences and barriers to care amidst COVID-19. Parents (N â€‹= â€‹95) completed self-report measures. Education was provided on interventions (e.g., individual therapy, medication), and acceptability assessed. Elevated stress and distress were observed. Parents indicated interest in services for parenting concerns, stress, anxiety, and depression. Individual therapy and telehealth were highly acceptable, while medication and group therapy were less accepted. Findings highlight the need for specific supports among parents amidst the pandemic. Factors that influence treatment preference warrant further attention. Implications for healthcare service delivery are discussed.

5.
Skin Health Dis ; 3(3): e200, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37275411

RESUMO

We present a series of five cases who presented to our institution with treatment-refractory mucosal ulceration, all of whom were subsequently diagnosed with paraneoplastic pemphigus (PNP). This case series highlights the diagnostic and treatment considerations for PNP - in particular, the steroid-dependent, recalcitrant, polymorphic manifestations; the combination of histopathological and clinical findings that may overlap with clinically similar diseases, for example, pemphigus vulgaris and lichen planus; the importance of immunopathological findings for its diagnosis, and the need for surveillance and management of life-threatening bronchiolitis obliterans.

6.
JMIR Ment Health ; 10: e38955, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36622747

RESUMO

BACKGROUND: The COVID-19 pandemic has created an epidemic of distress-related mental disorders such as depression, while simultaneously necessitating a shift to virtual domains of mental health care; yet, the evidence to support the use of virtual interventions is unclear. OBJECTIVE: The purpose of this study was to evaluate the efficacy of virtual interventions for depressive disorders by addressing three key questions: (1) Does virtual intervention provide better outcomes than no treatment or other control conditions (ie, waitlist, treatment as usual [TAU], or attention control)? (2) Does in-person intervention provide better outcomes than virtual intervention? (3) Does one type of virtual intervention provide better outcomes than another? METHODS: We searched the PubMed, EMBASE, and PsycINFO databases for trials published from January 1, 2010, to October 30, 2021. We included randomized controlled trials of adults with depressive disorders that tested a virtual intervention and used a validated depression measure. Primary outcomes were defined as remission (ie, no longer meeting the clinical cutoff for depression), response (ie, a clinically significant reduction in depressive symptoms), and depression severity at posttreatment. Two researchers independently selected studies and extracted data using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Risk of bias was evaluated based on Agency for Healthcare and Research Quality guidelines. We calculated odds ratios (ORs) for binary outcomes and standardized mean differences (SMDs) for continuous outcomes. RESULTS: We identified 3797 references, 24 of which were eligible. Compared with waitlist, virtual intervention had higher odds of remission (OR 10.30, 95% CI 5.70-18.60; N=619 patients) and lower posttreatment symptom severity (SMD 0.81, 95% CI 0.52-1.10; N=1071). Compared with TAU and virtual attention control conditions, virtual intervention had higher odds of remission (OR 2.27, 95% CI 1.10-3.35; N=512) and lower posttreatment symptom severity (SMD 0.25, 95% CI 0.09-0.42; N=573). In-person intervention outcomes were not significantly different from virtual intervention outcomes (eg, remission OR 0.84, CI 0.51-1.37; N=789). No eligible studies directly compared one active virtual intervention to another. CONCLUSIONS: Virtual interventions were efficacious compared with control conditions, including waitlist control, TAU, and attention control. Although the number of studies was relatively small, the strength of evidence was moderate that in-person interventions did not yield significantly better outcomes than virtual interventions for depressive disorders.

7.
Blood ; 116(23): 4885-93, 2010 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-20807887

RESUMO

There is increasing evidence that miRNA and transcription factors interact in an instructive fashion in normal and malignant hematopoiesis. We explored the impact of TEL-AML1 (ETV6-RUNX1), the most common fusion protein in childhood leukemia, on miRNA expression and the leukemic phenotype. Using RNA interference, miRNA expression arrays, and quantitative polymerase chain reaction, we identified miRNA-494 and miRNA-320a to be up-regulated upon TEL-AML1 silencing independently of TEL expression. Chromatin immunoprecipitation analysis identified miRNA-494 as a direct miRNA target of the fusion protein TEL-AML1. Using bioinformatic analysis as well as functional luciferase experiments, we demonstrate that survivin is a target of the 2 miRNAs. miRNA-494 and miRNA-320a were introduced to the cells by transfection and survivin expression determined by Western blot analysis. These miRNAs blocked survivin expression and resulted in apoptosis in a similar manner as TEL-AML1 silencing by itself; this silencing was also shown to be Dicer-dependent. miRNAs-494 and -320a are expressed at lower levels in TEL-AML1+ leukemias compared with immunophenotype-matched nonTEL-AML1 acute lymphoblastic leukemia subtypes, and within TEL-AML1+ leukemias their expression is correlated to survivin levels. In summary our data suggest that TEL-AML1 might exert its antiapoptotic action at least in part by suppressing miRNA-494 and miRNA-320a, lowering their expression causing enhanced survivin expression.


Assuntos
Apoptose/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Proteínas Associadas aos Microtúbulos/genética , Proteínas de Fusão Oncogênica/genética , Adolescente , Western Blotting , Linhagem Celular Tumoral , Criança , Pré-Escolar , Imunoprecipitação da Cromatina , Expressão Gênica , Humanos , Proteínas Inibidoras de Apoptose , Proteínas Associadas aos Microtúbulos/biossíntese , Análise de Sequência com Séries de Oligonucleotídeos , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Survivina , Transfecção
8.
Blood ; 114(9): 1859-63, 2009 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-19571318

RESUMO

Juvenile myelomonocytic leukemia is an aggressive myeloproliferative disorder characterized by malignant transformation in the hematopoietic stem cell compartment with proliferation of differentiated progeny. Seventy-five percent of patients harbor mutations in the NF1, NRAS, KRAS, or PTPN11 genes, which encode components of Ras signaling networks. Using single nucleotide polymorphism arrays, we identified a region of 11q isodisomy that contains the CBL gene in several JMML samples, and subsequently identified CBL mutations in 27 of 159 JMML samples. Thirteen of these mutations alter codon Y371. In this report, we also demonstrate that CBL and RAS/PTPN11 mutations were mutually exclusive in these patients. Moreover, the exclusivity of CBL mutations with respect to other Ras pathway-associated mutations indicates that CBL may have a role in deregulating this key pathway in JMML.


Assuntos
Regulação Leucêmica da Expressão Gênica , Leucemia Mielomonocítica Juvenil/genética , Mutação , Proteínas Proto-Oncogênicas c-cbl/genética , Criança , Pré-Escolar , Códon , Feminino , Células-Tronco Hematopoéticas/citologia , Homozigoto , Humanos , Lactente , Perda de Heterozigosidade , Masculino , Transdução de Sinais
9.
Blood Cells Mol Dis ; 45(3): 186-91, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20688547

RESUMO

High hyperdiploidy is the single largest subtype of childhood acute lymphoblastic leukemia (ALL) and is defined by the presence of 51-68 chromosomes in a karyotype. The 5 or more extra chromosomes characterizing this subtype are known to occur in a single mitotic event, prenatally. We screened for RAS mutations among 517 acute childhood leukemias (including 437 lymphocytic, of which 393 were B-cell subtypes) and found mutations in 30% of high hyperdiploids compared to only 10% of leukemias of other subtypes (P<0.0001). We assessed whether KRAS mutations occurred before birth using a PCR-restriction enzyme-mediated Taqman quantitative PCR reaction, and found no evidence for prenatal KRAS mutations in 14 patients tested. While RAS mutations were previously associated with prior chemical exposures in childhood and adult leukemias, in this study RAS-mutated cases were not significantly associated with parental smoking when compared to study controls. IGH rearrangements were backtracked in three RAS-positive patients (which were negative for KRAS mutation at birth) and found to be evident before birth, confirming a prenatal origin for the leukemia clone. We posit a natural history for hyperdiploid leukemia in which prenatal mitotic catastrophe is followed by a postnatal RAS mutation to produce the leukemic cell phenotype.


Assuntos
Aberrações Cromossômicas , Ploidias , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogênicas/genética , Proteínas ras/genética , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Proteínas Proto-Oncogênicas p21(ras)
10.
BMC Cancer ; 10: 513, 2010 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-20875128

RESUMO

BACKGROUND: Mutations in FLT3 result in activated tyrosine kinase activity, cell growth stimulation, and a poor prognosis among various subtypes of leukemia. The causes and timing of the mutations are not currently known. We evaluated the prevalence and timing of origin of FLT3 mutations in a population series of childhood leukemia patients from Northern California. METHODS: We screened and sequenced FLT3 mutations (point mutations and internal tandem duplications, ITDs) among 517 childhood leukemia patients, and assessed whether these mutations occurred before or after birth using sensitive "backtracking" methods. RESULTS: We determined a mutation prevalence of 9 of 73 acute myeloid leukemias (AMLs, 12%) and 9 of 441 acute lymphocytic leukemias (ALLs, 2%). Among AMLs, FLT3 mutations were more common in older patients, and among ALLs, FLT3 mutations were more common in patients with high hyperdiploidy (3.7%) than those without this cytogenetic feature (1.4%). Five FLT3 ITDs, one deletion mutation, and 3 point mutations were assessed for their presence in neonatal Guthrie spots using sensitive real-time PCR techniques, and no patients were found to harbor FLT3 mutations at birth. CONCLUSIONS: FLT3 mutations were not common in our population-based patient series in California, and patients who harbor FLT3 mutations most likely acquire them after they are born.


Assuntos
Mutação , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Tirosina Quinase 3 Semelhante a fms/genética , Adolescente , California , Criança , Pré-Escolar , Citogenética , Análise Mutacional de DNA , Diploide , Feminino , Humanos , Hibridização in Situ Fluorescente , Masculino , Reação em Cadeia da Polimerase
11.
Methods Mol Biol ; 538: 7-27, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19277581

RESUMO

Many of the acquired genetic changes that contribute to the molecular pathogenesis of leukemia are well characterized. The relative simplicity of the tumor genetics of the common subtypes of leukemia and the availability of archived material in the form of archived neonatal blood spots (ANB or Guthrie cards) has permitted the tracing of many genetic events to fetal origins using sensitive amplification methods. We here described methods for cloning translocations and other rearrangements for "backtracking" studies, and methods for sensitive detection of such rearrangements and a point mutation in ANB cards.


Assuntos
Aberrações Cromossômicas , Leucemia/embriologia , Leucemia/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Cromossomos Humanos/genética , DNA de Neoplasias/sangue , DNA de Neoplasias/genética , Humanos , Recém-Nascido , Leucemia/sangue , Mutação Puntual/genética , Reação em Cadeia da Polimerase/métodos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas p21(ras) , Translocação Genética , Proteínas ras/genética
13.
Arch Med Res ; 47(8): 677-683, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-28476195

RESUMO

BACKGROUND AND AIMS: Childhood acute lymphoblastic leukemia (ALL) is a biologically heterogeneous disease, and mutations in the KRAS and NRAS oncogenes are present at diagnosis in about one-fifth of cases. Ras mutations were previously associated with environmental exposures in leukemias as well as in many other cancer types. This study examined whether Ras mutation could define a unique etiologic group of childhood ALL associated with tobacco smoke, a well-established mutagen and carcinogen. METHODS: We included 670 children with ALL enrolled in a case-control study in California (1995-2013), including 50.6% Latinos. Parental and child exposure to tobacco smoke was obtained from interviews. Sanger sequencing was used to detect the common KRAS and NRAS hotspot mutations in diagnostic bone marrow DNA. ALL cases were also characterized for common chromosome abnormalities. In case-case analyses, logistic regression analyses were used to estimate odds ratios to describe the association between tobacco smoke exposure and childhood ALL with Ras mutations. RESULTS: KRAS or NRAS mutations were detected in ∼18% of children diagnosed with ALL. Ras mutations were more common among Latino cases compared with non-Latino whites and in high-hyperdiploid ALL. No associations were observed between parental smoking or child's passive exposure to smoke and Ras positive ALL. CONCLUSIONS: The apparent lack of association between tobacco smoke and Ras mutation in childhood ALL suggests that Ras mutations do not specifically define a tobacco-related etiologic pathway. Reasons for racial and ethnic differences in ALL are not well understood and could reflect differences in etiology that warrant further examination.


Assuntos
GTP Fosfo-Hidrolases/genética , Proteínas de Membrana/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Fumar/efeitos adversos , Poluição por Fumaça de Tabaco/efeitos adversos , California/epidemiologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Estudos de Associação Genética , Hispânico ou Latino , Humanos , Lactente , Masculino , Mutação , Razão de Chances , Leucemia-Linfoma Linfoblástico de Células Precursoras/etnologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/etiologia , Nicotiana , População Branca
14.
Cancer Res ; 73(8): 2540-50, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23400592

RESUMO

Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative neoplasm in children characterized by the overproduction of monocytic cells that infiltrate the spleen, lung, and liver. JMML remains a disease for which few curative therapies are available other than myeloablative hematopoietic stem cell transplant (HSCT); however, relapse remains a major cause of treatment failure and the long-term morbidities of HSCT for survivors are substantial. A hallmark feature of JMML is acquired hypersensitivity by clonal myeloid progenitor cells to granulocyte macrophage-colony stimulating factor (GM-CSF) via a largely unknown mechanism. Here, we identify c-Cbl (henceforth referred to as Cbl) as a GM-CSF receptor (GMR) adaptor protein that targets Src for ubiquitin-mediated destruction upon GM-CSF stimulation and show that a loss of negative regulation of Src is pivotal in the hyperactivation of GMR signaling in Cbl-mutated JMML cells. Notably, dasatinib, an U.S. Food and Drug Administration-approved multikinase inhibitor that also targets Src family, dramatically attenuated the spontaneous and GM-CSF-induced hypersensitive growth phenotype of mononuclear cells from peripheral blood and bone marrow collected from JMML patients harboring Cbl or other known JMML-associated mutations. These findings reveal Src kinase as a critical oncogenic driver underlying JMML.


Assuntos
Resistencia a Medicamentos Antineoplásicos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Leucemia Mielomonocítica Juvenil/metabolismo , Quinases da Família src/antagonistas & inibidores , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Subunidade beta Comum dos Receptores de Citocinas/genética , Subunidade beta Comum dos Receptores de Citocinas/metabolismo , Dasatinibe , Células HEK293 , Humanos , Leucemia Mielomonocítica Juvenil/genética , Leucemia Mielomonocítica Juvenil/terapia , Fosforilação/efeitos dos fármacos , Ligação Proteica , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-cbl/genética , Proteínas Proto-Oncogênicas c-cbl/metabolismo , Pirimidinas/farmacologia , Tiazóis/farmacologia , Ubiquitinação/efeitos dos fármacos , Quinases da Família src/metabolismo
15.
Nat Genet ; 42(9): 794-800, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20694012

RESUMO

CBL encodes a member of the Cbl family of proteins, which functions as an E3 ubiquitin ligase. We describe a dominant developmental disorder resulting from germline missense CBL mutations, which is characterized by impaired growth, developmental delay, cryptorchidism and a predisposition to juvenile myelomonocytic leukemia (JMML). Some individuals experienced spontaneous regression of their JMML but developed vasculitis later in life. Importantly, JMML specimens from affected children show loss of the normal CBL allele through acquired isodisomy. Consistent with these genetic data, the common p.371Y>H altered Cbl protein induces cytokine-independent growth and constitutive phosphorylation of ERK, AKT and S6 only in hematopoietic cells in which normal Cbl expression is reduced by RNA interference. We conclude that germline CBL mutations have developmental, tumorigenic and functional consequences that resemble disorders that are caused by hyperactive Ras/Raf/MEK/ERK signaling and include neurofibromatosis type 1, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome and Legius syndrome.


Assuntos
Deficiências do Desenvolvimento/genética , Mutação em Linhagem Germinativa , Leucemia Mielomonocítica Juvenil/genética , Proteínas Proto-Oncogênicas c-cbl/genética , Pré-Escolar , Criptorquidismo/complicações , Criptorquidismo/genética , Análise Mutacional de DNA , Deficiências do Desenvolvimento/complicações , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa/fisiologia , Humanos , Lactente , Recém-Nascido , Leucemia Mielomonocítica Juvenil/complicações , Masculino , Linhagem , Proteínas Proto-Oncogênicas c-cbl/fisiologia
16.
Contemp Drug Probl ; 36(1-2): 217-244, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-22563133

RESUMO

Given the considerable variability in drinking practices among Asian American groups, the generalizations that suggest an increase in their alcohol use associated with acculturation need to be questioned. Also, the experience of children of immigrants growing up in the United States may be much more complex than a focus on acculturation can capture. Informed by the theory of segmented assimilation, this study addresses two research questions: 1) Is acculturation associated with alcohol use of Korean American adolescents? and 2) What other social, economic, and cultural forces influence their alcohol use? Survey data collected from 202 adolescents of Korean descent in Southern California were used. Multivariate regression analyses revealed that acculturation was not a significant predictor of most measures of alcohol use, while peer influence, scholastic achievement/aspirations, and current smoking were predictive. Gender and social class were unrelated to drinking. Findings suggest focusing research on an integrative approach to understanding drinking in complex social, economic, and social contexts may be useful.

17.
Cancer Res ; 68(23): 9935-44, 2008 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-19047175

RESUMO

TEL-AML1 (ETV6-RUNX1) is the most common translocation in the childhood leukemias, and is a prenatal mutation in most children. This translocation has been detected at a high rate among newborns ( approximately 1%); therefore, the rate-limiting event for leukemia seems to be secondary mutations. One such frequent mutation in this subtype is partial deletion of chromosome 12p, trans from the translocation. Nine del(12p) breakpoints within six leukemia cases were sequenced to explore the etiology of this genetic event, and most involved cryptic sterile translocations. Twelve of 18 del(12p) parent sequences involved in these breakpoints were located in repeat regions (8 of these in long interspersed nuclear elements). This stands in contrast with TEL-AML1, in which only 21 of 110 previously assessed breakpoints (19%) occur in DNA repeats (P=0.0001). An exploratory assessment of archived neonatal blood cards revealed significantly more long interspersed nuclear element CpG methylations in individuals at birth who were later diagnosed with TEL-AML1 leukemia, compared with individuals who did not contract leukemia (P=0.01). Nontemplate nucleotides were also more frequent in del(12p) than in TEL-AML1 junctions (P=0.004), suggesting formation by terminal deoxynucleotidyl transferase. Assessment of six archived neonatal blood cards indicated that no del(12p) rearrangements backtracked to birth, although two of these patients were previously positive for TEL-AML1 using the same assay with comparable sensitivity. These data are compatible with a two-stage natural history: TEL-AML1 occurs prenatally, and del(12p) occurs postnatally in more mature cells with a structure that suggests the involvement of retrotransposon instability.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Retroelementos , Criança , Deleção Cromossômica , Cromossomos Humanos Par 12 , Metilação de DNA , Humanos
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