Establishment of a t(11;19), KMT2A Rearranged B-ALL Cell Line for Preclinical Evaluation and Novel Therapeutics Development for Refractory Infant Leukemia.

Leukemia, diagnosed in children less than 12 months of age, is a rare condition with an aggressive disease presentation and poor response to conventional chemotherapeutic agents. In addition, the unique vulnerability of the affected population does not always permit the use of markedly intense regimens with higher doses of cytotoxic agents. However, the unique biology of these leukemic cells also provides opportunities for the identification of effective and potentially well-tolerated targeted therapeutic strategies. In this report, we describe the establishment and characterization of a cell line from the blasts of an infant diagnosed with refractory B-cell acute lymphoblastic leukemia (ALL) carrying the characteristic histone lysine methyltransferase 2A (KMT2A) gene rearrangement. This cell line consists of rapidly proliferating clones of cells with chemosensitivity patterns previously described for KMT2A rearranged leukemia cells, including relative resistance to glucocorticoids and sensitivity to cytarabine. We also show effective targetability with menin inhibitors, indicating the activity of abnormal KMT2A-related pathways and the potential utility of this cell line in comprehensive drug library screens. Overall, our findings report the establishment and in vitro validation of a cell line for research into key aspects of infant leukemia biology and targeted therapeutics development.

Multisystemic fusariosis with fulminant evolution

Abstract This report presents the case of a 13-year-old female patient with history of acute myeloid leukemia, who, after a bone marrow transplant, began to vomit and experienced rapidly progressive deterioration of consciousness, in addition to disseminated erythematous-violaceous macules, and some blisters with hemorrhagic content inside. Skin biopsy evidenced intravascular filamentous structures. A blood culture confirmed the presence of Fusarium oxysporum. Intravenous treatment with voriconazole was initiated. The patient evolved unfavorably with multiple necrotic skin lesions, ischemic brain lesions, and death.

Multisystemic fusariosis with fulminant evolution.

This report presents the case of a 13-year-old female patient with history of acute myeloid leukemia, who, after a bone marrow transplant, began to vomit and experienced rapidly progressive deterioration of consciousness, in addition to disseminated erythematous-violaceous macules, and some blisters with hemorrhagic content inside. Skin biopsy evidenced intravascular filamentous structures. A blood culture confirmed the presence of Fusarium oxysporum. Intravenous treatment with voriconazole was initiated. The patient evolved unfavorably with multiple necrotic skin lesions, ischemic brain lesions, and death.

Treatment of Childhood Acute Myeloid Leukemia in Uruguay: Results of 2 Consecutive Protocols Over 20 Years.

We evaluated the outcome of 71 children with de novo acute myeloid leukemia enrolled in 2 consecutive protocols in the main pediatric hospital in Uruguay. In the LAM97 protocol (n=34), patients received, as consolidation, autologous or allogeneic hematopoietic stem cell transplantation (HSCT), depending on the availability or not of a matched sibling donor. In the LAM08 protocol (n=37), patients were stratified into risk groups, autologous HSCT was abandoned, and allogeneic HSCT was limited to intermediate-risk patients with matched sibling donor and to all patients who fulfilled the high-risk criteria. Complete remission was achieved in 91% and 92% of patients in LAM97 and LAM08, respectively. Deaths in complete remission were 9.6% and 17.6%, respectively. The incidence of relapse was significantly higher in LAM97, 35.4%, versus 12.5% in LAM08. The 5-year event-free survival and overall survival were 50.0% and 55.9% in LAM97 and 59.9% and 64.8% in LAM08. The 5-year overall survival rates in each of the risk groups were 85.7% and 100% for low risk, 50.0% and 61.2% for intermediate risk, and 42.9% and 50.0% for high risk in LAM97 and LAM08 protocols, respectively. Survival has improved over the last 2 decades, and results are comparable to those published in Europe and North America.

High Risk Neuroblastoma in Uruguay. Where are we? / Neuroblastoma de Alto Riesgo en Uruguay. ¿Dónde estamos? / Neuroblastoma de Alto Risco no Uruguai. Onde estamos?

Introdução: El neuroblastoma es el tumor sólido extracraneal más frecuente en niños. Aproximadamente el 50 % de los pacientes son clasificados como de alto riesgo, con base en características clínicas, biológicas e histológicas. Objetivo: Describir a la población asistida en el Centro Hemato-Oncológíco Pediátrico (CHOP) del Centro Hospitalario Pereira Rossell (CHPR) con diagnóstico de neuroblastoma de alto riesgo, su tratamiento y sobrevida. Método: Estudio descriptivo y retrospectivo de todos los pacientes con neuroblastoma de alto riesgo diagnosticados en el CHOP entre el 2001 y el 2015. En el CHOP se ubica el Registro Nacional de Cáncer Pediátrico, así como también el Archivo de Historias Clínicas de todos los pacientes. Los datos son recolectados y analizados por el sector de estadística. Resultados: Se diagnosticaron 35 pacientes, de los cuales 20 (57%) eran varones con mediana de edad de 36,6 meses (5-93), localización suprarrenal 23 (66%) y 100% estadio IV. Metástasis, médula ósea y hueso: 27 (71%). Treinta y tres pacientes recibieron autotransplante de progenitores hematopoyéticos (TPH) (94%). Estatus previo a TPH, remisión completa: 19 (58 %), remisión parcial: 14 (42%). Mortalidad relacionada al tratamiento: 15 % y de recaídas: 68 %. Mediana de tiempo de recaída: 15 meses (3-52). La probabilidad de sobrevida global y sobrevida libre de eventos a 5 años fue de 37,8% ± 8,4 y 23,8% ± 7,3 (mediana de seguimiento 40 meses). Conclusión: A pesar del tratamiento intensivo y de las medidas de soporte adecuadas, el pronóstico en los niños con neuroblastoma de alto riesgo sigue siendo pobre en nuestro país. Es necesario incorporar nuevas estrategias terapéuticas aún no disponibles en nuestro medio.

Introduction: Neuroblastoma is the most common extracranial solid tumor in children. Approximately 50% of patients are classified as high risk on the basis of clinical, biological, and histological characteristics. Objective: To describe the population of patients diagnosed with high-risk neuroblastoma at the Centro Hemato-Oncológíco Pediátrico (CHOP, Center for Pediatric Hematology and Oncology) of the Centro Hospitalario Pereira Rossell (CHPR, Pereira Rossell Hospital), in terms of their treatment and survival. Method: Descriptive, retrospective study of all patients diagnosed with highrisk neuroblastoma at the CHOP between 2001 and 2015. The National Registry of Pediatric Cancer is located at the CHOP, as is the Archive of Patient Clinical Histories. The data are collected and analyzed by the statistics sector. Results: Among the 35 patients diagnosed, 20 (57%) were men, the median age was 36.6 months (range, 5-93 months), and the tumor had an adrenal location in 23 (66%). All of the tumors were classified as stage IV. Metastasis to the bone marrow or bone was seen in 27 (71%). Thirty-three patients (94%) received autologous hematopoietic stem-cell transplantation (HSCT). The status prior to HSCT was complete remission in 19 (58%) and partial remission in 14 (42%). The treatment-related mortality rate was 15%, and the relapse rate was 68%. The median time to relapse was 15 months (3-52 months). The probability of overall survival and 5-year event-free survival was 37.8% ± 8.4 and 23.8% ± 7.3 (median follow-up of 40 months), respectively. Conclusion: Despite intensive treatment and adequate support measures, the prognosis for high-risk neuroblastoma in children remains poor in Uruguay. There is a need to incorporate new therapeutic strategies not yet available in our country.

Introducción:O neuroblastoma é o tumor sólido extracraniano mais frequente em crianças. Aproximadamente 50% dos pacientes são classificados como de alto risco considerando as características clínicas, biológicas e histológicas. Objetivo: Descrever a população atendida no Centro Hemato-Oncológíco Pediátrico (CHOP) do Centro Hospitalario Pereira Rossell (CHPR) com diagnóstico de neuroblastoma de alto risco, seu tratamento e sobrevida. Método: Estudo descritivo, retrospectivo, de todos os pacientes com neuroblastoma de alto risco diagnosticados no CHOP, no período entre 2001 e 2015. O Registro Nacional de Câncer Pediátrico está localizado no CHOP, bem como o Arquivo de Histórias Clínicas de todos os pacientes. Os dados são coletados e analisados pelo setor estatístico. Resultados: Foram diagnosticados 35 pacientes. Vinte (57%) eram do sexo masculino. Mediana de idade: 36,6 meses (5-93). Localização suprarrenal: 23 (66%). Estádio IV 100%. Metástases, medula óssea e osso: 27 (71%). Trinta e três pacientes receberam transplante de células-tronco hematopoiéticas (TCTH) (94%). Status prévio a TCTH, remissão completa: 19 (58%), remissão parcial: 14 (42%). Incidência de mortalidade relacionada ao tratamento: 15% e de recaídas: 68%. Mediana do tempo de recaída: 15 meses (3-52). A probabilidade de sobrevida global e sobrevida livre de eventos aos cinco anos foi de 37,8% ± 8,4 e 23,8% ± 7,3 (mediana de seguimento 40 meses). Conclusão: Apesar do tratamento intensivo e medidas de suporte adequadas, o prognóstico em crianças com neuroblastoma de alto continua sendo pobre no Uruguai. É necessário incorporar novas estratégias terapêuticas que ainda não estão disponíveis em nosso meio

Neuroblastoma en niños menores de 18 meses. Experiencia de 10 años en Centro Hematooncológico / Neuroblastoma less than 18 months of age. 10 years experience in pediatric hematooncologic of the Pereira Rossell Hospital Center

Introducción: el neuroblastoma es el tumor maligno más frecuente en los lactantes. Su curso clínico es variable, desde la regresión espontánea a la progresión maligna, y los factores pronósticos son múltiples, como edad, estadio, amplificación de N-myc y ploidía tumoral. Se describen las características de todos los pacientes con neuroblastoma menores de 18 meses asistidos en CHOP. Pacientes y métodos: estudio observacional, descriptivo y retrospectivo en el período entre 31 de enero de 2000 y 31 de enero de 2011. El diagnóstico se realizó por histología y aspirado de médula ósea. Los pacientes se estadificaron por INSS; el tratamiento se decidió según estadio y riesgo. Resultados: se incluyeron 22 pacientes menores de 18 meses (52% de todos los neuroblastomas), con una media de edad de 9,6 meses. Once pacientes se encontraban en estadio 4. La localización más frecuente fue suprarrenal; presentaban metástasis 13 pacientes. Quince niños recibieron poliquimioterapia y 20 fueron tratados quirúrgicamente. La amplificación del gen N-myc se demostró en tres pacientes. La sobrevida global fue de 77% y la sobrevida libre de enfermedad fue de 77%. Discusión y conclusiones: la mayor parte de los casos fueron diagnosticados en niños menores de 9 meses. Fueron más frecuentes los estadios 4 y 1. No se pudo demostrar asociación entre N-myc y estadio de enfermedad. La sobrevida fue excelente.

Introduction: neuroblastoma is the most common malignant tumor in infants. Its clinical behavior is variable, from spontaneous regression to malignant progression; prognostic factors are multiple, such as age, stage, N-myc amplification and tumor ploidy. We describe the characteristic of all patients with neuroblastoma less than 18 months of age assisted in CHOP. Patients and methods: retrospective, observational and descriptive study in the period between 31/1/00 y 31/01/11. Diagnose was made from histology and bone marrow aspirate. Patients were classified by INSS stage; treatment was decided according to stage and risk. Results: 22 patients were included (52% of all neuroblastomas), with a mean age of 9,6 months. Eleven patients were classified in stage 4. The most frequent localization was adrenal; 14 patients presented methastasis. Fifteen patients received chemotherapy and 20 were surgically intervened. N-myc amplification was detected in 3 patients. Overall survival was 77% and event-free survival was 77%. Discussion and conclusions: the majority of cases were diagnosed in children younger than 9 months. Stages 4 and 1 were the most frequent. No association between N-myc and stage could be determined. Overall and event-free survival were excellent.

Trasplante alogénico haploidéntico de progenitores hematopoyéticos en pediatría en Uruguay / Haploidentical allogeneic hematopoietic transplant of hematopoietic parents in pediatrics in Uruguay

Introducción: el trasplante alogénico de progenitores hematopoyéticos (TPH) es actualmente la única opción de tratamiento curativo disponible para un número de neoplasias hematológicas de alto riesgo, así como para algunas enfermedades no malignas hereditarias o adquiridas. El TPH haploidéntico (HI) es una opción válida para pacientes que no tienen un hermano HLA-idéntico. Objetivo: describir los resultados obtenidos con TPH HI en pediatría. Material y método: en el año 2005 se inició en el Centro Hemato-Oncológico Pediátrico del Centro Hospitalario Pereira Rossell un programa de TPH HI para aquellos pacientes sin donante relacionado HLA-idéntico. Resultados: se trasplantaron 32 pacientes, 24 con neoplasias hematológicas y 8 con enfermedades no malignas. Se utilizaron dos estrategias de prevención de la enfermedad injerto contra huésped (EICH), depleción de linfocitos T (DLT) in vitro (28 pacientes) y DLT alorreactivos in vivo con altas dosis de ciclofosfamida postrasplante (4 pacientes). Veintisiete pacientes (84%) tuvieron un implante con quimerismo total del donante. La incidencia de EICH agudo y crónico fue de 26,9% y 11,8%, respectivamente. La muerte no relacionada a recaída al año del trasplante fue de 21,9%. Con una mediana de seguimiento de 32 meses, la sobrevida global a dos años fue de 52,4%. Conclusiones: el TPH HI ha demostrado ser una opción factible en nuestro medio para aquellos pacientes sin donante HLA-idéntico. Los resultados son comparables a los obtenidos con otros donantes alternativos y con costos más accesibles. Uruguay está hoy día mejor posicionado para ofrecer un TPH a los pacientes que así lo requieran...

Neuroblastoma en niños menores de 18 meses. Experiencia de 10 años en Centro Hematooncológico Pediátrico del Centro Hospitalario Pereira Rossel / Neuroblastome in children younger than 18 months. Ten years experience at the Pediatric Hemato Oncological Center of the Centro Hospitalario Pereira Rossell

El neuroblastoma es el tumor maligno más frecuente en los lactantes. Su curso clínico es variable, desde la regresión espontánea a la progresión maligna, y los factores pronósticos son múltiples, como edad, estadio, amplificación de N-myc y ploidía tumoral. Se describen las características de todos los pacientes con neuroblastoma menores de 18 meses asistidos en CHOP. Pacientes y métodos: estudio observacional, descriptivo y retrospectivo en el período entre 31 de enero de 2000 y 31 de enero de 2011. El diagnóstico se realizó por histología y aspirado de médula ósea. Los pacientes se estadificaron por INSS; el tratamiento se decidió según estadio y riesgo. Resultados: se incluyeron 22 pacientes menores de 18 meses (52% de todos los neuroblastomas), con una media de edad de 9,6 meses. Once pacientes se encontraban en estadio 4. La localización más frecuente fue suprarrenal; presentaban metástasis 13 pacientes. Quince niños recibieron poliquimioterapia y 20 fueron tratados quirúrgicamente. La amplificación del genN-myc se demostró en tres pacientes. La sobrevida global fue de 77% y la sobrevida libre de enfermedad fuede 77%. Discusión y conclusiones: la mayor parte de los casosfueron diagnosticados en niños menores de 9 meses. Fueron más frecuentes los estadios 4 y 1. No se pudo demostrar asociación entre N-myc y estadio de enfermedad. La sobrevida fue excelent...

Cytotoxicity, drug combinability, and biological correlates of ABT-737 against acute lymphoblastic leukemia cells with MLL rearrangement.

BACKGROUND: ABT-737 is a BH3 mimetic small-molecule inhibitor that binds with high affinity to Bcl-2 to induce apoptosis in malignant cells and has shown promise as an effective anti-leukemic agent in pediatric preclinical tests. This study focuses on the effects of ABT-737 on leukemia cells with MLL rearrangement and identifies some of the biological correlates of its activity. PROCEDURE: Cells were cultured in the presence of increasing concentrations of ABT-737 alone or in combination with other agents. After 4 days in culture, cell growth inhibition was measured by Alamar blue assay. The expression and activation of potential intracellular targets of ABT-737 activity were determined by Western blot analysis. RESULTS: Significant Bcl-2 expression was detected in all infant leukemia cells investigated. ABT-737 induced cell death in all cell lines studied although the IC(50) values differed somewhat between cell lines. Western blot analysis identified the effects of ABT-737 on survival and apoptosis-regulatory proteins PARP, caspase-8, and cytochrome-c. Drug combination studies indicated synergy with distinct anti-neoplastic agents, including the multi-tyrosine kinase inhibitor sunitinib. This effective drug synergy appears to be mediated by the combined inhibition of Bcl-2 and intracellular signaling pathways. CONCLUSIONS: We describe the in vitro studies to demonstrate the activity and drug combinability of ABT-737 against MLL rearranged leukemia cells. In addition, identification of the molecular changes that occur in the presence of ABT-737 provides information regarding effective target validation and target modulation analyses in future clinical trials.

Childhood acute lymphoblastic leukemia (ALL) presenting with severe osteolysis: a model to study leukemia-bone interactions and potential targeted therapeutics.

Interference with the molecular mechanisms that generate tumor supportive niches in the bone microenvironment is a rational approach to inhibit the growth of hematological malignancies. However, the advancement of knowledge in this area has been slowed down by the lack of in vitro models to facilitate the screening of potential candidate agents. The rare cases of acute lymphoblastic leukemia (ALL) in children presenting with extensive bone involvement may represent an exaggerated form of some aspects of the normal tumor-bone interactions. Thus, these cases can provide insight into processes that are otherwise challenging to uncover. The authors describe the case of a 6-year-old child who presented with severe osteopenia that resolved at the time of leukemic remission. Compared to control sera, serum taken at disease presentation contained increased levels of a group of osteolytic cytokines and was effective in activating preosteoclast cells in culture. Based on these findings, the authors describe an experimental model to identify agents that would interfere with leukemia mediated osteolytic process.

Effects of Hsp90 inhibition in neuroblastoma: analysis of drug sensitivity, target modulation and the influence of bone marrow microenvironment.

Heat shock protein 90 (Hsp90) safeguards the structural integrity and function of many of the key growth regulatory proteins found in malignant cells. Consequently, among the new generation targeted therapeutics, heat shock protein inhibitors have the unique property of being able to target an expansive array of divergent molecular mechanisms involved in cancer growth and metastasis. 17-N-Allylamino-17-demethoxygeldanamycin (17-AAG) is one such agent that has been shown to bind to Hsp90 and thus reduce the stability and activity of many key growth regulatory molecules and pathways. A number of recent clinical trials have investigated the maximum tolerated dose, toxicity and pharmacokinetic profiles of 17-AAG in pediatric patients with recurrent tumors. In this study, we describe the effects of 17-AAG against a panel of neuroblastoma (NB) cell lines with respect to cytotoxicity, target modulation and inhibition of vascular endothelial growth factor (VEGF) expression. 17-AAG was found to inhibit the growth of all NB cell lines tested, though effective inhibitory concentrations varied among cell lines. 17-AAG also suppressed the expression of VEGF. The cytotoxic effect of 17-AAG on tumor cells was diminished when co-cultured with bone marrow stromal cells suggesting a potential role for the microenvironment in tumor drug interactions. Findings from target modulation analysis as well as drug combination assays provide a frame-work to formulate effective protocols for the treatment of NB.