Genomic alterations in a cohort of pediatric acute myeloid leukemia patients at two cancer centers in Colombia.

Few studies identifying genomic aspects in pediatric acute myeloid leukemia patients in Latin American countries have been reported. The aim of this study was to identify genomic alterations, clinical characteristics and outcomes in a cohort of pediatric AML patients. This descriptive observational cohort study included patients with confirmed de novo acute myeloid leukemia up to 18 years of age. Cytogenetics and conventional FISH analysis, next-generation sequencing and PCR testing were performed. The correlation of genomic data with treatment response and outcomes were analyzed. Of the 51 patients analyzed, 67.4% had a cytogenetic abnormality and 74.5% had a genetic variant. FLT3 variants (ITD or TKD D835) were found in 27.4%, followed by NRAS (21.6%), KRAS (13.7%) and WT1 and KIT (11.8%). Patients were stratified by risk (66.6% high-risk) after the end of induction. FLT3-ITD was associated with relapse (OR 11.25; CI 1.89-66.72, p 0.006) and NRAS with death during induction (OR 16.71; CI 1.51-184.59, p 0.022). Our study highlights the importance of rapid incorporation of genetic testing in pediatric AML in Colombia, as it directly affects treatment decisions and outcomes. Incorporation of targeted therapies with conventional chemotherapy is an increasingly urgent need in pediatric patients.

Pharmacogenetics of ABCB1, CDA, DCK, GSTT1, GSTM1 and outcomes in a cohort of pediatric acute myeloid leukemia patients from Colombia.

BACKGROUND AND AIM: Different studies have shown pharmacogenetic variants related to drug toxicity in acute myeloid leukemia (AML) patients. Our aim was to identify the association between ABCB1, CDA, DCK, GSTT1, and GSTM1 variants with clinical outcomes and toxicity in pediatric patients with AML. METHODS: Fifty-one confirmed de novo AML pediatric patients were included. A SNaPshot™ assay and conventional PCR were used to evaluate ABCB1, CDA, DCK, GSTT1, and GSTM1 variants. Clinical outcomes and toxicity associations were evaluated using odds ratios and Chi-square analysis. RESULTS: Patients carrying ABCB1 (1236C > T, rs1128503) GG genotype in had a 6.8 OR (CI 95% 1.08-42.73, p = .044) for cardiotoxicity as compared to patients carrying either AA or GA genotypes 0.14 OR (CI 95% 0.023-0.92, p = .044). For ABCB1 (1236G > A rs1128503/2677C > A/T rs2032582/3435G > A rs1045642) AA/AA/AA combined genotypes had a strong association with death after HSTC OR 13.73 (CI 95% 1.94-97.17, p = .009). Combined genotypes GG/CC/GG with CDA (79A > C, rs2072671) CA genotype or CDA (-451G > A, rs532545) CT genotype, had a 4.11 OR (CI 95% 2.32-725, p = .007) and 3.8 OR (CI 95% 2.23-6.47, p = .027) with MRD >0.1% after first chemotherapy cycle, respectively. CONCLUSION: Our results highlight the importance of pharmacogenetic analysis in pediatric AML, particularly in populations with a high degree of admixture, and might be useful as a future tool for patient stratification for treatment.

[Identification of epithelial-mesenchymal transition markers (EMT) by immunohistochemistry in pediatric osteosarcoma and association with clinical outcomes]. / Identificación de marcadores de transición epitelio-mesénquima (TEM) por inmunohistoquímica en osteosarcoma pediátrico y asociación con desenlaces clínicos.

The epithelial-mesenchymal transition (EMT) is the ability of epithelial and mesenchymal cells to exchange phenotypes transiently. Its identification in carcinomatous cells has been associated with aggressive clinical phenotypes. In sarcomas, this ability is under study. OBJECTIVE: to evaluate the expression of two transcription factors involved in EMT by immunohistochemistry in pediatric osteosarcoma and its association with clinical outcomes. PATIENTS AND METHOD: A retrospective cohort study in children under 18 years of age with osteosarcoma diagnosis. Immunohistochemistry was performed for Snail and Twist-1 expressions from samples collected at the time of diagnosis. Correlations between immunohistochemistry and the clinical outcomes and overall survival were performed. RESULTS: 53 patients were included. There were 26 positive cytoplasmic cases (49.1%) in Snail expression and were correlated with the presence of multiple metastases (p = 0.02) and distant bone metastases (p = 0.01). On the other hand, 45 cases (84.9%) were positive in Twist-1 expression in the nuclear location, showing no association with the analyzed clinical variables. CONCLUSIONS: Snail and Twist-1 were frequently expressed in pediatric cases of osteosarcoma. Cytoplasmic Snail was correlated with the presence of multiple metastatic disease and distant bone metastases. The positivity of both markers suggests the activation of these proteins as regulators of EMT events in this tumor, suggesting a role in the phenomena related to the clinical presentation of the disease.

Philadelphia-like acute lymphoblastic leukemia: Characterization in a pediatric cohort in a referral center in Colombia.

BACKGROUND: Philadelphia-like (Ph-like) acute lymphoblastic leukemia (ALL) is a subtype of pediatric leukemia with high risk factors and poor outcome. There are few reports of its prevalence in Latin America. AIM: This study evaluated the frequency and clinical and biological characteristics of Ph-like ALL in a pediatric cancer center in Colombia. METHODS: The Ph-like genetic profile was analyzed by a low-density array (LDA). Samples from patients with Ph-like ALL were analyzed by fluorescent in situ hybridization for cytokine receptor like factor 2 (CRLF2) and ABL proto-oncogene 1, non-receptor tyrosine kinase (ABL1) rearrangements. Copy number variations were assessed by multiplex ligation probe amplification. RESULTS: Data from 121 patients were analyzed. Fifteen patients (12.4%) had Ph-like ALL, and these patients had significantly higher leukocyte counts at diagnosis and higher levels of minimal residual disease on days 15 and 33 of induction than patients without the Ph-like subtype. There were no significant differences in sex, age, or response to prednisone at day 8 between the two groups. CRLF2 rearrangements were identified in eight patients, and ABL1 rearrangements were identified in two patients. Other genetic alterations alone or in combination were identified in 77% of patients, including deletions in cyclin dependent kinase inhibitor 2 A/B (46.2%), IKAROS family zinc finger 1 (38.3%), and paired box 5 (30.8%). CONCLUSIONS: Ph-like ALL had a 12.4% prevalence in our cohort of patients with pediatric ALL. The identification of this group of patients has importance for risk stratification and future targeted therapy.

Sensitization to Drug Treatment in Precursor B-Cell Acute Lymphoblastic Leukemia Is Not Achieved by Stromal NF-κB Inhibition of Cell Adhesion but by Stromal PKC-Dependent Inhibition of ABC Transporters Activity.

Cell adhesion to stromal support and the associated intracellular signaling are central to drug resistance, therefore blocking both has been effective in increasing drug sensitization in leukemia. The stromal Ser/Thr protein kinase C (PKC) has been found to be important for conferring protection to leukemic cells. We aimed at elucidating the intracellular signals connected to cell adhesion and to stromal PKC. We found that NF-κB and Akt were up-regulated in mesenchymal stem cells (MSC) after binding of B-cell acute lymphoblastic leukemia (B-ALL) cells. Nevertheless, Akt inhibition did not induce B-ALL cell detachment. In spite of a clear activation of the NF-κB signaling pathway after B-ALL cell binding (up-regulation NF-κB1/2, and down-regulation of the IKBε and IKBα inhibitors) and an important reduction in cell adhesion after NF-κB inhibition, sensitization to the drug treatment was not observed. This was opposite to the PKC inhibitors Enzastaurin and HKPS, a novel chimeric peptide inhibitor, that were able to increase sensitization to dexamethasone, methotrexate, and vincristine. PLCγ1, Erk1/2, and CREB appear to be related to PKC signaling and PKC effect on drug sensitization since they were contra-regulated by HKPS when compared to dexamethasone-treated cells. Additionally, PKC inhibition by HKPS, but not by Enzastaurin, in MSC reduced the activity of three ABC transporters in leukemic cells treated with dexamethasone, a new indirect mechanism to increase sensitization to drug treatment in B-ALL cells. Our results show the validity of targeting the functional characteristic acquired and modulated during cell-to-cell interactions occurring in the leukemic niche.

Susceptibility to thiopurine toxicity by TPMT and NUDT15 variants in Colombian children with acute lymphoblastic leukemia / Asociación de variantes genéticas en TPMT y NUDT15 con los eventos de toxicidad durante la terapia de mantenimiento en niños colombianos con Leucemia Linfoide Aguda

Abstract Objective: This study aimed to correlate the genetic profile of the NUDT15 and TPMT genes with the side effects of the treatment of pediatric patients with acute lymphoid leukemia who were undergoing maintenance therapy at a tertiary care hospital in 2017. Methods: This was an analytical, longitudinal, observational study in which the genotypes of the genes of interest were determined by PCR allelic discrimination with TaqMan® probes in patients receiving chemotherapy during the maintenance phase in the Pediatric Hematology and Oncology Unit in 2017. Sociodemographic and clinical data corresponding to the first six months of their maintenance chemotherapy were collected, and the correlation between the genotypes obtained and the development of side effects during the maintenance phase of chemotherapy in these patients was evaluated. Results: Seventy pediatric patients were included in the study. Genetic analyses were carried out of these for NUDT15 and TPMT (rs1800462 and rs1800460) on 68 patients, while for the rs1142345 polymorphism, typing was achieved in 42 patients. 4/68 patients were heterozygous for NUDT15, and the same number of patients were heterozygous for rs1800462 and rs1142345, while for rs1800460, 6 heterozygous patients were identified. No statistically significant association was identified between the genetic variants and the outcomes of interest. Conclusion: Studies with a larger population size are needed and the evaluation of other genetic variants that may influence the development of side effects during maintenance chemotherapy.

Resumen Objetivo: la finalidad de este estudio fue evaluar las asociaciones entre los perfiles de los genes NUDT15 y TPMT con los efectos adversos del tratamiento de mantenimiento en pacientes pediátricos con Leucemia Linfoblástica Aguda atendidos en un hospital de referencia durante el 2017. Métodos: Este fue un estudio observacional analítico, de corte longitudinal en el que los genotipos de los genes de interés fueron determinados mediante PCR de discriminación alélica con sondas TaqMan® en pacientes que estaban recibiendo quimioterapia de mantenimiento en la Unidad de Oncohematología Pediátrica durante el 2017. Los datos clínicos y sociodemográficos correspondientes a los primeros 6 meses de sus tratamientos de mantenimiento fueron colectados, y se evaluó la correlación entre los genotipos identificados y el desarrollo de efectos secundarios en estos pacientes. Resultados: setenta pacientes fueron incluidos en el estudio, de estos, los análisis genéticos para NUDT15 y TPMT (rs1800462 and rs1800460) fueron realizados en 68 pacientes, en tanto que para el polimorfismo rs1142345 se logró la tipificación en 42 pacientes. 4/68 pacientes fueron heterocigotos para NUDT15 y el mismo número de pacientes fueron heterocigotos para rs1800462 and rs1142345, mientras que para rs1800460, 6 pacientes heterocigotos fueron identificados. No se identificaron asociaciones estadísticamente significantes entre las variants genéticas y los resultados clínicos de interés. Conclusiones: Estos hallazgos resaltan la importancia de realizar estudios de este tipo con un mayor número de sujetos de estudio, así como plantean la necesidad de evaluar otras variantes genéticas que podrían tener algún impacto en el desarrollo de efectos secundarios durante la quimioterapia de mantenimiento.

Leukemia-Induced Cellular Senescence and Stemness Alterations in Mesenchymal Stem Cells Are Reversible upon Withdrawal of B-Cell Acute Lymphoblastic Leukemia Cells.

Leukemic cell growth in the bone marrow (BM) induces a very stressful condition. Mesenchymal stem cells (MSC), a key component of this BM niche, are affected in several ways with unfavorable consequences on hematopoietic stem cells favoring leukemic cells. These alterations in MSC during B-cell acute lymphoblastic leukemia (B-ALL) have not been fully studied. In this work, we have compared the modifications that occur in an in vitro leukemic niche (LN) with those observed in MSC isolated from B-ALL patients. MSC in this LN niche showed features of a senescence process, i.e., altered morphology, increased senescence-associated ß-Galactosidase (SA-ßGAL) activity, and upregulation of p53 and p21 (without p16 expression), cell-cycle arrest, reduced clonogenicity, and some moderated changes in stemness properties. Importantly, almost all of these features were found in MSC isolated from B-ALL patients. These alterations rendered B-ALL cells susceptible to the chemotherapeutic agent dexamethasone. The senescent process seems to be transient since when leukemic cells are removed, normal MSC morphology is re-established, SA-ßGAL expression is diminished, and MSC are capable of re-entering cell cycle. In addition, few cells showed low γH2AX phosphorylation that was reduced to basal levels upon cultivation. The reversibility of the senescent process in MSC must impinge important biological and clinical significance depending on cell interactions in the bone marrow at different stages of disease progression in B-ALL.

Results of the implementation of the PETHEMA LPA 99 protocol for treating children with acute promyelocytic leukemia in Bogotá, Colombia / Resultados de la implementación del protocolo PETHEMA LPA 99 en el tratamiento de niños con leucemia promielocítica aguda en Bogotá, Colombia

Abstract Introduction: In the United States, between 4 and 8% of children with acute myeloid leukemia have acute promyelocytic leukemia (APL), but a higher incidence of this malignancy has been reported in Latin America (20%-28%). The implementation of the PETHEMA LPA 99 protocol, designed for the treatment of APL in adults, has shown an overall survival (OS) >80%. Objective: To describe the results obtained after the implementation of the PETHEMA LPA 99 protocol to treat children with APL at the Fundación Hospital Pediátrico La Misericordia in Bogotá, D.C., Colombia. Materials and methods: Descriptive and retrospective cohort study. The medical records of 30 pediatric patients (<18 years) with APL, who were treated using the PETHEMA LPA 99 protocol between January 2005 and December 2012, were reviewed. Data on the following variables were obtained: early death, death during induction therapy, OS, event-free survival (EFS), and relapse. Results: The male sex was predominant (60%) among the 30 patients included in the study. Regarding risk classification, 13 (43%) were classified as high-risk patients, 12 (40%) as medium-risk, and 5 (17%) as low-risk. Seven individuals died: 2 before receiving cancer treatment, 2 during induction therapy, and 3 after relapse. Relapse was reported in 5 patients. There were no deaths during the consolidation or maintenance phases. OS was 75.4% (95%CI: 55.1-87.5) and EFS was 64.3% (95%CI: 40-80.5). Moreover, OS at 11 years was 80%, 91.7%, and 59.2% for low-risk, intermediate-risk, and high-risk patients, respectively. The median follow-up time was 6.35 years (0-11.43 years). Conclusions: In general, the implementation of the PETHEMA LPA 99 protocol to treat APL in the study population showed very satisfactory results. Therefore, its use in pediatric population is recommended, taking into account the adjustments described in the protocol regarding the characteristics of this age group.

Resumen Introducción. En Estados Unidos de América, entre 4 y 8% de niños con leucemias mieloides agudas tienen leucemia promielocítica aguda (LPA), mientras que en Latinoamérica se ha descrito una mayor incidencia de esta neoplasia (20-28%). La implementación del protocolo PETHEMA LPA 99, diseñado para el tratamiento de LPA en adultos, ha mostrado una supervivencia global (SG) >80%. Objetivo. Describir los resultados de la aplicación del protocolo PETHEMA LPA 99 en el tratamiento de niños con LPA en la Fundación Hospital Pediátrico la Misericordia, en Bogotá D.C., Colombia. Materiales y métodos. Estudio de cohorte descriptivo y retrospectivo. Se revisaron las historias clínicas de 30 pacientes pediátricos (<18 años) con LPA que recibieron tratamiento mediante el protocolo PETHEMA LPA 99 entre enero de 2005 y diciembre de 2012. Se obtuvieron datos sobre las siguientes variables: muerte temprana, muerte en terapia de inducción, SG, supervivencia libre de evento (SLE) y recaída. Resultados. De los 30 pacientes, la mayoría eran de sexo masculino (60%). Respecto a la clasificación de riesgo, 13 (43%) fueron clasificados como pacientes de riesgo alto; 12 (40%), de riesgo intermedio, y 5 (17%), de riesgo bajo. 7 individuos murieron: 2 antes del tratamiento oncológico, 2 durante la terapia de inducción y 3 luego de presentar recaída. Se reportó recaída en 5 pacientes. No hubo muertes durante las fases de consolidación o de mantenimiento. La SG fue de 75.4% (IC95%: 55.1-87.5) y la SLE fue de 64.3% (IC95%: 40-80.5). La SG a 11 años fue de 80%, 91.7% y 59.2% para los pacientes de riesgo bajo, riesgo intermedio y riesgo alto, respectivamente. La mediana de seguimiento fue 6.35 años (0-11.43 años). Conclusiones. En general, la implementación del protocolo PETHEMA LPA 99 en el tratamiento de la LPA en la población de estudio mostró resultados muy satisfactorios, por lo que se recomienda su uso en población pediátrica, teniendo en cuenta los ajustes recomendados por el protocolo en relación con las características de este grupo etario.

Early-onset Cardiotoxicity assessment related to anthracycline in children with leukemia. A Prospective Study.

BACKGROUND: Acute leukemias are the most frequent malignancies in children. Advances in treatment have improved the overall survival to 80%. Almost 10% of children with cancer develop clinical cardiac toxicity. Total anthracycline cumulative dose is a risk factor for early-onset cardiotoxicity. OBJECTIVE: To describe the incidence of early-onset cardiotoxicity in children with acute leukemia treated with chemotherapy. METHODS: A prospective descriptive study of patients >1 y and <18 years diagnosed with acute leukemia. Assessed with electrocardiograma, echocardiography, and blood biomarkers at diagnosis and during the follow-up. RESULTS: 94 patients with acute lymphoblastic leukemia and 18 with acute myeloid leukemia were included. 20 patients (17.9%) developed early-onset cardiotoxicity. Statistically significant data was seen after anthracycline dose >150 mg/m2, between the first echocardiographic evaluation and posterior analyses in the left ventricular fraction ejection with Teicholz p 0.05, Simpson p 0.018 and GLS p 0.004. In this study, there was no relation between blood biomarkers and cardiotoxicity. CONCLUSIONS: Cancer therapeutic-related cardiac dysfunction is related to anthracycline cumulative dose. In this study, echocardiographic follow-up was useful to predict risk factors for early cardiac dysfunction.

Early-onset Cardiotoxicity assessment related to anthracycline in children with leukemia. A Prospective Study / Evaluación de la cardiotoxicidad temprana asociada al tratamiento con antraciclinas en niños con Leucemia. Estudio prospectivo

Abstract Background: Acute leukemias are the most frequent malignancies in children. Advances in treatment have improved the overall survival to 80%. Almost 10% of children with cancer develop clinical cardiac toxicity. Total anthracycline cumulative dose is a risk factor for early-onset cardiotoxicity. Objective: To describe the incidence of early-onset cardiotoxicity in children with acute leukemia treated with chemotherapy. Methods: A prospective descriptive study of patients >1 y and <18 years diagnosed with acute leukemia. Assessed with electrocardiograma, echocardiography, and blood biomarkers at diagnosis and during the follow-up. Results: 94 patients with acute lymphoblastic leukemia and 18 with acute myeloid leukemia were included. 20 patients (17.9%) developed early-onset cardiotoxicity. Statistically significant data was seen after anthracycline dose >150 mg/m2, between the first echocardiographic evaluation and posterior analyses in the left ventricular fraction ejection with Teicholz p 0.05, Simpson p 0.018 and GLS p 0.004. In this study, there was no relation between blood biomarkers and cardiotoxicity. Conclusions: Cancer therapeutic-related cardiac dysfunction is related to anthracycline cumulative dose. In this study, echocardiographic follow-up was useful to predict risk factors for early cardiac dysfunction.

Resumen Antecedentes: Las leucemias son la principal causa de cáncer infantil. Los avances en el tratamiento han llevado a los pacientes a una supervivencia global hasta del 80%. Cerca del 10% de los niños con cáncer tienen toxicidad cardiovascular sintomática, la dosis acumulada de antraciclinas es un factor de riesgo para afección cardíaca. Objetivo: Describir la frecuencia de afectación cardíaca temprana en niños con leucemias agudas que recibieron tratamiento antineoplásico. Métodos: Estudio prospectivo observacional, de pacientes <18 años con diagnóstico confirmado de leucemia aguda. Fueron evaluados con electrocardiograma, ecocardiograma bidimensional y biomarcadores séricos en diferentes momentos durante el tratamiento. Resultados: Se evaluaron 94 pacientes con leucemia linfoide aguda y 18 con leucemia mieloide aguda. 20 pacientes (17.9%) tuvieron disfunción cardiaca de inicio temprano. Se observaron diferencias estadísticamente significativas, después de recibir 150 mg/m2 de antraciclinas, entre la evaluación del ecocardiograma basal y evaluaciones posteriores de la fracción de eyección ventricular izquierda por Teicholz p 0.05, fracción de eyección ventricular izquierda por Simpson p 0.018 y la deformación longitudinal global p 0.004. No se encontraron alteraciones en los niveles séricos de las troponinas y péptido natriurético cerebral. Conclusiones: La disfunción cardíaca relacionada con quimioterapia estuvo directamente relacionada con las dosis acumuladas de antraciclinas. En este estudio el uso del ecocardiograma como método de seguimiento permitió identificar factores predictores de riesgo para disfunción cardiaca temprana.

Susceptibility to thiopurine toxicity by TPMT and NUDT15 variants in Colombian children with acute lymphoblastic leukemia.

Objective: This study aimed to correlate the genetic profile of the NUDT15 and TPMT genes with the side effects of the treatment of pediatric patients with acute lymphoid leukemia who were undergoing maintenance therapy at a tertiary care hospital in 2017. Methods: This was an analytical, longitudinal, observational study in which the genotypes of the genes of interest were determined by PCR allelic discrimination with TaqMan® probes in patients receiving chemotherapy during the maintenance phase in the Pediatric Hematology and Oncology Unit in 2017. Sociodemographic and clinical data corresponding to the first six months of their maintenance chemotherapy were collected, and the correlation between the genotypes obtained and the development of side effects during the maintenance phase of chemotherapy in these patients was evaluated. Results: Seventy pediatric patients were included in the study. Genetic analyses were carried out of these for NUDT15 and TPMT (rs1800462 and rs1800460) on 68 patients, while for the rs1142345 polymorphism, typing was achieved in 42 patients. 4/68 patients were heterozygous for NUDT15, and the same number of patients were heterozygous for rs1800462 and rs1142345, while for rs1800460, 6 heterozygous patients were identified. No statistically significant association was identified between the genetic variants and the outcomes of interest. Conclusion: Studies with a larger population size are needed and the evaluation of other genetic variants that may influence the development of side effects during maintenance chemotherapy.

Objetivo: la finalidad de este estudio fue evaluar las asociaciones entre los perfiles de los genes NUDT15 y TPMT con los efectos adversos del tratamiento de mantenimiento en pacientes pediátricos con Leucemia Linfoblástica Aguda atendidos en un hospital de referencia durante el 2017. Métodos: Este fue un estudio observacional analítico, de corte longitudinal en el que los genotipos de los genes de interés fueron determinados mediante PCR de discriminación alélica con sondas TaqMan® en pacientes que estaban recibiendo quimioterapia de mantenimiento en la Unidad de Oncohematología Pediátrica durante el 2017. Los datos clínicos y sociodemográficos correspondientes a los primeros 6 meses de sus tratamientos de mantenimiento fueron colectados, y se evaluó la correlación entre los genotipos identificados y el desarrollo de efectos secundarios en estos pacientes. Resultados: setenta pacientes fueron incluidos en el estudio, de estos, los análisis genéticos para NUDT15 y TPMT (rs1800462 and rs1800460) fueron realizados en 68 pacientes, en tanto que para el polimorfismo rs1142345 se logró la tipificación en 42 pacientes. 4/68 pacientes fueron heterocigotos para NUDT15 y el mismo número de pacientes fueron heterocigotos para rs1800462 and rs1142345, mientras que para rs1800460, 6 pacientes heterocigotos fueron identificados. No se identificaron asociaciones estadísticamente significantes entre las variants genéticas y los resultados clínicos de interés. Conclusiones: Estos hallazgos resaltan la importancia de realizar estudios de este tipo con un mayor número de sujetos de estudio, así como plantean la necesidad de evaluar otras variantes genéticas que podrían tener algún impacto en el desarrollo de efectos secundarios durante la quimioterapia de mantenimiento.

Dual Targeting of Stromal Cell Support and Leukemic Cell Growth by a Peptidic PKC Inhibitor Shows Effectiveness against B-ALL.

Mesenchymal stem cells (MSC) favour a scenario where leukemic cells survive. The protein kinase C (PKC) is essential to confer MSC support to leukemic cells and may be responsible for the intrinsic leukemic cell growth. Here we have evaluated the capacity of a chimeric peptide (HKPS), directed against classical PKC isoforms, to inhibit leukemic cell growth. HKPS was able to strongly inhibit viability of different leukemic cell lines, while control HK and PS peptides had no effect. Further testing showed that 30% of primary samples from paediatric B-cell acute lymphoblastic leukaemia (B-ALL) were also strongly affected by HKPS. We showed that HKPS disrupted the supportive effect of MSC that promote leukemic cell survival. Interestingly, ICAM-1 and VLA-5 expression increased in MSC during the co-cultures with B-ALL cells, and we found that HKPS inhibited the interaction between MSC and B-ALL cells due to a reduction in the expression of these adhesion molecules. Of note, the susceptibility of B-ALL cells to dexamethasone increased when MSC were treated with HKPS. These results show the relevance of these molecular interactions in the leukemic niche. The use of HKPS may be a new strategy to disrupt intercellular communications, increasing susceptibility to therapy, and at the same time, directly affecting the growth of PKC-dependent leukemic cells.

Resultados del Protocolo ACHOP 2006 en los niños con leucemia linfoblástica aguda en la Fundación HOMI Hospital de la Misericordia de Bogotá, en el periodo 2007 - 2012 / Results of the 2006 ACHOP protocol on children with acute lymphoblastic leukemia at the HOMI Hospital of Misericordia Foundation in Bogotá in the period 2007 to 2012

RESUMEN Introducción: la leucemia aguda es la neoplasia más común en niños, constituye aproximadamente el 25 % de todos los tumores en la infancia. En Colombia la proporción de curación, alrededor del 50 %, es inferior a lo informado en países desarrollados. Objetivo: el objetivo principal es determinar la supervivencia global y libre de eventos, la proporción de abandono y recaída de los niños con el diagnóstico de leucemia linfoide aguda tratados con el Protocolo ACHOP 2006. Materiales y métodos: estudio descriptivo de tipo cohorte de 183 pacientes menores de 18 años, con el diagnóstico confirmado de leucemia linfoide aguda, que recibieron tratamiento en la Fundación HOMI desde el 2007 hasta el 2012. Los análisis de supervivencia se obtuvieron con curvas de Kaplan-Meier. Resultados: se analizó la supervivencia global a 2, 3 y 5 años con resultados de 89 %, 87,3 % y 74,7 % (IC 95 % 67-80,9), respectivamente. A los 5 años la supervivencia para el grupo de riesgo estándar fue de 78,6 % (IC 95 % 68,3 - 85,1) y para el de riesgo alto 61,9 % (IC 95 % 50,7- 73). La supervivencia libre de evento, al considerar el abandono y traslado a otra institución como evento, fue de 56,3 % (IC 95 % 45,5-65,8) a los 5 años. La mortalidad en inducción fue de 3,8 %, la mortalidad relacionada con el tratamiento fue 3,4 %. Treinta y dos pacientes (17 %) recayeron, el abandono fue de 16,4 % y los traslados de 10,4 %. La principal complicación del tratamiento fueron las infecciones. Conclusiones: la supervivencia global es aceptable para un país de recursos limitados. Los eventos de abandono y traslado son muy altos. Deben aunarse esfuerzos para disminuir estas situaciones que empeoran el pronóstico de la enfermedad.

SUMMARY Introduction: Acute leukemia is the most common neoplasm in children, accounting for approximately 25% of all tumors in childhood. In Colombia the cure proportion, around 50%, are lower than reported in developed countries. Objective: The main objective is to determine the global and event-free survival of children with diagnosis of lymphoblastic leukemia, all treated with the ACHOP Protocol 2006, from 2007 to 2012. The secondary objectives are to describe mortality, abandonment, relapse and major complications related to treatment. Material and methods: A descriptive cohort study of 183 patients under 18 years of age, with a confirmed diagnosis of acute lymphoblastic leukemia, who were treated at the Foundation of the Misericordia (HOMI) from 2007 to 2012, was performed. The survival dates were obtained by analysis with Kaplan-Meier curves. Results: We analyzed overall survival at 2, 3 and 5 years with results of 89%, 87.3% and 74.7 % (95% CI 67 - 80.9) respectively. At 5 years survival for the standard risk group was 78.6 % (95 % CI 68.3-85.1) and 61.9 % (95 % CI 50.7-73) for the high risk group. The event-free survival, considering the abandonment and transfer to another institution as an event, was 56.3 % (95% CI 45.5 - 65.8) at 5 years. Mortality in induction was 3.8 %, mortality related to treatment was 3.4 %, 32 patients (17 %) relapsed, abandonment was 16.4 % and transfers 10.4 %. The main complication of the treatment was infections. Conclusions: Overall survival is acceptable for a country with limited resources, the events of abandonment and transfers are very high. Efforts should be made to reduce these situations that worsen the prognosis of the disease.

Características de los sangrados en niños con hemofilia en un centro de referencia en Colombia / Characteristics of bleeding in children with hemophilia in a reference center in Colombia

Resumen Introducción: La hemofilia es el trastorno hemorrágico congénito más frecuente en los varones, los pacientes con enfermedad severa pueden tener sangrados espontáneos que llevan a discapacidad. Objetivo: Describir las características de los sangrados y los aspectos clínicos y demográficos de un grupo de pacientes con diagnóstico de hemofilia en un centro de referencia de la ciudad de Bogotá. Materiales y métodos: Estudio descriptivo de serie de casos, en menores de 18 años con hemofilia, entre mayo 1 a diciembre 31 de 2014. Resultados: Se incluyeron 51 pacientes, 33/51 tuvieron sangrado, 109 sangrados, el sangrado más frecuente fue hemartrosis y en niños con anticuerpos inhibidores. 22 pacientes tenían hemofilia severa, 18 moderada y 11 leve. 18/22 pacientes severos sangraron y tuvieron 87 sangrados, 14/18 (77%) pacientes con artropatía tuvieron sangrado, con 74 eventos en total, 19/33 pacientes sin artropatía tuvieron 35 eventos. El grupo con mayor frecuencia de sangrados tenía entre 5 y 9 años. De los 81 episodios traumáticos, la mayoría fueron jugando y haciendo deporte; Se presentaron 19 sangrados espontáneos y nueve relacionados con procedimientos. 84 sangrados fueron en temporada escolar y 25 en vacaciones. Al momento de los sangrados en 76 episodios estaban acompañados por padres o familiares y 69 episodios ocurrieron en el hogar (62,4%). Conclusiones: Los sangrados fueron más frecuentes en niños con anticuerpos inhibidores, enfermedad severa, con artropatía, en temporada escolar y estando acompañados. No hubo mayor frecuencia de sangrados en aquellos con disfunción familiar.

Abstract Introduction: Hemophilia is the most common congenital hemorrhagic disorder in males. Patients with severe disease may have spontaneous bleeding leading to disability. Objective: To describe the bleedings and clinical features of children diagnosed with hemophilia and treated in a reference center in Bogotá. Methodology:Descriptive study of a case series of children (under 18 years) diagnosed with hemophilia, between May 1st and December 31th 2014. Results: Fifty-one patients were included, 33/51 experienced 109 bleedings. Most common type were hemarthrosis and children with inhibitory antibodies had more bleeding episodes. Twenty-two patients had severe hemophilia, 18 moderate and 11 mild. In 18 of 22 severe patients, there were 87 bleeding episodes. 14/33 patients with arthropathy (77%) experienced 74 bleeding events while the rest referred only 35. Patients between 5 to 9 years old had the highest frequency of bleeding. Among the 81 traumatic episodes, most frequent activities were playing and sport practicing; there were 19 spontaneous bleedings and nine were related to procedures. 89 bleeds occurred during school days and 25 on vacation. At the time of bleeding, in 76 episodes, patients were accompanied by family members. Conclusions: Bleeding was more frequent in children with severe disease, with arthropathy, during school time and while being accompanied. Bleedings did not occurred with a higher frequency in children with family dysfunction.

Supresión del eje hipotálamo-hipófisis-suprarrenal después de la quimioterapia de inducción en niños con leucemia linfoide aguda / Hypothalamus-pituitary-adrenal axis suppression following induction chemotherapy in children with acute lymphoblastic leukemia / Supressão do eixo hipotálamo-hipófises-suprarrenal depois da quimioterapia de indução em crianças com leucemia linfoide aguda

Introducción: se ha informado insuficiencia suprarrenal (IS) en 46 % a 81,5 % de los niños con leucemia linfoide aguda (LLA) que reciben esteroides durante la quimioterapia. Materiales y métodos: para evaluar la frecuencia de dicha IS se hizo un estudio prospectivo de 40 pacientes menores de 18 años (media: 8,5 años) con diagnóstico nuevo de LLA. Se les midieron el cortisol basal y la adrenocorticotropina (ACTH). Todos recibieron prednisolona (60 mg/m2/día) durante 5 semanas; tres días después de suspendidos los esteroides se hizo una prueba de estimulación con 1 µg de ACTH. En los que tenían el cortisol anormal (<18 µg /dL) se hicieron pruebas de estimulación con ACTH en los días 7, 14 y 30 hasta que se normalizó el cortisol (>18 µg /dL). Resultados: en 29 de los 40 pacientes (72,5 %) se halló IS después del primer estímulo con ACTH, pero al día 30 en todos se había normalizado el nivel de cortisol. Todos los pacientes con IS fueron mayores de 5 años (HR: 4,69; IC95 %: 1,44-15,32; p = 0,011). Conclusiones: los esteroides empleados durante el tratamiento de la LLA pueden causar IS, y el riesgo es más alto en los niños mayores de 5 años. Se sugiere hacer seguimiento durante los episodios de estrés porque es posible que requieran suplencia con esteroides.

Background: Adrenal insufficiency has been reported in 46 % to 81.5 % of children receiving corticosteroids for acute lymphoblastic leukemia (ALL). Methodology: To assess the frequency of such insufficiency, 40 patients under 18 years (mean: 8.5 years) with new diagnosis of ALL were studied. Base-line cortisol and adrenocorticotropin (ACTH) levels were measured, and they received 5-week therapy with prednisolone. After 3 days off-steroid therapy, a stimulation test with ACTH 1 µg was done. In patients with abnormal cortisol (<18 µg /dL) new ACTH tests were done and cortisol levels were determined at days 7, 14 and 30 until cortisol post-stimulation levels were normal. Results: Three days after the last steroid dose 29/40 (72.5 %) had adrenal insufficiency after ACTH stimulus. At day 30 no one had abnormal cortisol levels after ACTH stimulus. All patients with adrenal suppression were over 5 years (HR 4.69; CI95 %: 1.44-15.32; p = 0.011). Conclusion: Steroids used during ALL treatment may cause adrenal insufficiency. Patients over 5 years are at high risk of developing adrenal suppression. We suggest to follow-up those patients with stress episodes after induction chemotherapy as steroid supplementation may be indicated.

Introdução: informou-se insuficiência suprarrenal (IS) em 46 % a 81,5 % das crianças com leucemia linfoide aguda (LLA) que recebem esteroides durante a quimioterapia. Materiais e métodos: para avaliar a frequência de dita IS se fez um estudo prospectivo de 40 pacientes menores de 18 anos (média: 8,5 anos) com diagnóstico novo de LLA. Se lhes mediram o cortisol basal e a adrenocorticotrófica (ACTH). Todos receberam prednisona (60 mg/m2/dia) durante 5 semanas; três dias depois de suspendidos os esteroides se fez uma prova de estimulação com 1 µg de ACTH. Nos que tinham o cortisol anormal (<18 µg /DL) fizeram-se provas de estimulação com ACTH nos dias 7, 14 e 30 até que se normalizou o cortisol (>18 µg /DL). Resultados: em 29 dos 40 pacientes (72,5 %) achouse IS depois do primeiro estímulo com ACTH, mas ao dia 30 em todos se tinha normalizado o nível de cortisol. Todos os pacientes com IS foram maiores de 5 anos (HR: 4,69; IC95 %: 1,44-15,32; p = 0,011). Conclusões: os esteroides empregados durante o tratamento da LLA podem causar IS, e o risco é mais alto nas crianças maiores de 5 anos. Sugere-se fazer seguimento durante os episódios de estresse porque é possível que requeiram suplência com esteroides.

Tumores germinales gonadales en niños: experiencia de 20 años en un centro de referencia pediátrico / Gonadal germ cell tumors in children: experience of 20 years in a pediatric referral center

Antecedentes. Los tumores de células germinales son un grupo heterogéneo de neoplasias que corresponden al 1-3% de los tumores en pediatría. Por lo general, se manifiestan clínicamente con masa testicular o dolor abdominal. Objetivo. Describir las características de los pacientes con tumores germinales gonadales en un centro de referencia de cáncer pediátrico en Colombia. Materiales y métodos. Este artículo hace una revisión retrospectiva recopilando 20 años de experiencia en el diagnóstico y manejo de estos tumores en la Fundación Hospital de la Misericordia. Resultados. Se encontraron 79 pacientes, 35 hombres y 44 mujeres, con un promedio de edad, al diagnóstico, de 6 años. El teratoma fue la neoplasia más frecuente en el sexo femenino y el tumor del seno endodérmico en el masculino. El 70,9% de los pacientes se diagnosticaron en estadio I; se tienen datos de marcadores tumorales en 84,8%. El 98,7% se manejaron con cirugía y 58,2% recibieron además quimioterapia, especialmente protocolo BEP. 96% alcanzaron remisión de la enfermedad, 3 pacientes fallecieron. Conclusiones. El estudio demuestra buenos resultados en el manejo de los tumores germinales gonadales con el protocolo establecido de manejo quirúrgico y quimioterapia, se encontró una baja tasa de recurrencia en el periodo evaluado y alto porcentaje de niños libres de enfermedad.

Background. Germ cell tumors are a heterogeneous group of neoplasms corresponding to 1-3% of pediatric tumors. They usually manifest clinically as testicular mass or abdominal pain. Objective. To make a description of gonadal germ cell tumor types in pediatric referral center in Colombia. Materials and methods. This article takes a retrospective review compiling 20 years of experience in diagnosis and management of these tumors in the Fundación Hospital de La Misericordia. Results. We found 79 patients, 35 men and 44 women, with an average age at diagnosis of 6 years. The teratoma was the most common neoplasia in females and endodermal sinus tumor in men. 70.9% of patients were diagnosed with stage I. In 84,8% measuring tumor markers were obtained. 98.7% were managed with surgery and 58.2% also received chemotherapy, especially BEP protocol. 96% achieved disease remission, 3 patients died. Conclusions. The study shows good results in the management of gonadal germ cell tumors with the established protocol and low recurrence rate in the evaluated period and high rates of children free of disease, were found a low rate of recurrence in the assessment period and high percentage of free of disease.

[18FDG-PET/CT cost-effectiveness compared to CT at the end of treatment in pediatric Hodgkin's lymphoma patients]. / Costo-efectividad de 18FDG-PET/CT vs CT al final del tratamiento en pacientes pediátricos con Linfoma Hodgkin.

OBJECTIVE: Estimating the cost-effectiveness of 18FDG-PET/CT (positron emission tomography) compared to computer tomography (CT) followed by 18FDG-PET/CT as a confirmatory test for a positive case at the end of treatment in Hodgkin's lymphoma (HL) patients under 18 years-old. METHODS: A decision tree was built for comparing 18FDG-PET/CT to CT followed by 18FDG-PET/CT as a confirmatory test for a positive case in detecting residual lesions; outcome was measured in life years gained (LYG). The cost-effectiveness ratio was calculated; the threshold was 3 times the per capita GDP per LYG. Values were expressed in Colombian pesos for 2010 (1 US dollar=$ 1,897.89) and submitted to deterministic and probabilistic sensitivity analysis. RESULTS: Assuming a difference of 13 months in true positives' life expectancy compared to that for false negatives, the cost of an additional LYG with 18FDG-PET/CT compared to CT followed by 18FDG-PET/CT as a confirmatory test for a positive case when evaluating the end of pediatric HL patients' treatment was $ 34,508,590 (COP). CONCLUSION: If differential life-expectancy between true positives and false negatives is at least 1.03 years, then using 18FDG-PET/CT for evaluating the end of HL pediatric patients' therapy is a cost-effective strategy for Colombia.

Evaluation of the diagnostic performance of platelet-derived indices for the differential diagnosis of thrombocytopenia in pediatrics / Evaluación del rendimiento diagnóstico de los índices plaquetarios en el diagnóstico diferencial de las trombocitopenias en pediatría

Background. Platelet-derived indices have a well-established correlation with the differential diagnosis of thrombocytopenia in adult-based research. These indices include mean platelet volume, platelet distribution width, and platelet-large cell ratio. Objective. To determine the values of platelet-derived indices in a pediatric population with diagnoses of thrombocytopenia and their etiologic correlation. Materials and methods. Analytic observational diagnostic-test study. The population for this analytical study was pediatric patients between 6 months and 18 years of age who had thrombocytopenia (<100x10(9)/L). The study period was 18 months long. Results. Of 54 subjects, 18 (33.3%) were diagnosed with idiopathic thrombocytopenic purpura, and 36 (66.7%) were diagnosed with acute leukemia. Mean age was 7.4 years and 6.8 years for immune thrombocytopenic purpura and acute leukemia, respectively. Mean platelet distribution width values for immune thrombocytopenic purpura and acute leukemia were 15.08 fL and 10.73, respectively. Mean MPV for immune thrombocytopenic purpura and acute leukemia was 11.7 fL and 9.8 fL, respectively. Mean platelet-large cell ratio was 38.26% and 24.97% for idiopathic thrombocytopenic purpura and acute leukemia, respectively. Differences in these three distinct platelet indices between idiopathic thrombocytopenic purpura and acute leukemia were statistically significant (p=0.00). The area under the ROC curve for platelet-derived indices showed that they were adequate for defining the causes of thrombocytopenia. MPV and platelet-large cell ratio had an area under the curve of 0.89 and 0.88, respectively, while platelet size deviation width had an area under the curve of 0.903. Conclusions. Platelet-derived indices could be useful in the initial approach for the differential diagnosis of pediatric patients with thrombocytopenia.

Antecedentes. Los índices plaquetarios tienen buena correlación con la etiología de la trombocitopenia en estudios realizados en adultos. Estos son: volumen plaquetario medio, ancho de distribución plaquetaria y porcentaje de plaquetas grandes. Objetivo. Determinar las características de los índices plaquetarios en población pediátrica con trombocitopenia y su posible correlación etiológica. Materiales y métodos. Estudio de prueba diagnóstica observacional analítico. Realizado con pacientes entre 6 meses y 18 años ingresados en un período de 18 meses con trombocitopenia <100x10(9)/L. Resultados. 54 pacientes: 18 (33,3%) con púrpura trombocitopénica inmune y 36 (66,7%) con leucemia aguda. Edad media para púrpura trombocitopénica inmune 7,4 años y 6,8 para leucemia aguda. Valores de ancho de distribución plaquetaria con media de 15,08 fL en púrpura trombocitopénica inmune y 10,73 para leucemia aguda. Media del volumen plaquetario medio para púrpura trombocitopénica inmune 11,7 fL y de 9,8 fL para leucemia aguda. Porcentaje de plaquetas grandes la media para púrpura trombocitopénica inmune 38,26% y 24,97% para leucemia aguda. Las diferencias de los tres índices para cada una de las enfermedades fueron estadísticamente significativas (p=0,00). Las curvas de Característica Operativa del Receptor de los índices plaquetarios fueron parámetros suficientes para distinguir las causas de trombocitopenia: volumen plaquetario medio y porcentaje de plaquetas grandes con un área bajo la curva de 0,89 y 0,88 y ancho de distribución plaquetaria 0,903. Conclusiones. Los índices plaquetarios fueron útiles para el acercamiento inicial al diagnóstico diferencial de trombocitopenias en niños.

Costo-efectividad de 18FDG-PET/CT vs CT al final del tratamiento en pacientes pediátricos con Linfoma Hodgkin / 18FDG-PET/CT cost-effectiveness compared to CT at the end of treatment in pediatric Hodgkin's lymphoma patients

Objetivo Estimar la costo-efectividad de 18FDG-PET/CT comparado con CT seguido de 18FDG-PET/CT como prueba confirmatoria de un caso positivo en la evaluación al final del tratamiento en pacientes menores de 18 años con Linfoma Hodgkin (LH). Métodos Se construyó un árbol de decisión donde se comparó el uso de 18FDG-PET/CT con CT seguido de 18FDG-PET/CT como prueba confirmatoria de un caso positivo en la detección de lesión residual. El resultado se midió en Años de Vida Ganados (AVG). Se calculó la razón de costo-efectividad incremental. Se utilizó como umbral 3 veces el PIB per cápita por año AVG. Valores expresados en pesos colombianos de 2010 (1 US dólar = $ 1 897,89) Se realizaron análisis de sensibilidad univariados, bivariados y probabilísticos. Resultados Suponiendo un diferencial en AVG entre verdaderos positivos y falsos negativos de 13 meses, el costo de un AVG adicional con 18FDG-PET/CT comparado con CT seguido de 18FDG-PET/CT como prueba confirmatoria de un caso positivo en la evaluación al final del tratamiento en pacientes pediátricos con LH fue $ 34 508 590. Conclusión Si el diferencial de esperanza de vida entre verdaderos positivos y falsos negativos es de al menos un 1,03 años, el uso de 18FDG-PET/CT en la evaluación al final del tratamiento de pacientes pediátricos con LH, es una estrategia costo-efectiva para Colombia.

Objective Estimating the cost-effectiveness of 18FDG-PET/CT (positron emission tomography) compared to computer tomography (CT) followed by 18FDG-PET/CT as a confirmatory test for a positive case at the end of treatment in Hodgkin's lymphoma (HL) patients under 18 years-old. Methods A decision tree was built for comparing 18FDG-PET/CT to CT followed by 18FDG-PET/CT as a confirmatory test for a positive case in detecting residual lesions; outcome was measured in life years gained (LYG). The cost-effectiveness ratio was calculated; the threshold was 3 times the per capita GDP per LYG. Values were expressed in Colombian pesos for 2010 (1 US dollar=$ 1,897.89) and submitted to deterministic and probabilistic sensitivity analysis. Results Assuming a difference of 13 months in true positives' life expectancy compared to that for false negatives, the cost of an additional LYG with 18FDG-PET/CT compared to CT followed by 18FDG-PET/CT as a confirmatory test for a positive case when evaluating the end of pediatric HL patients' treatment was $ 34,508,590 (COP). Conclusion If differential life-expectancy between true positives and false negatives is at least 1.03 years, then using 18FDG-PET/CT for evaluating the end of HL pediatric patients' therapy is a cost-effective strategy for Colombia.

Tumor neuroectodérmico primitivo de la pared torácica: tumor de Askin en niños / Primitive neuroectodermal tumor of the chest wall: Askin tumor in children

Resumen Antecedentes. El tumor neuroectodérmico primitivo (TNEP) de la pared torácica o Tumor de Askin, es un tumor maligno clasificado dentro de los TNEP periféricos y perteneciente a los tumores de la familia del sarcoma de Ewing (FSE). Este tipo de neoplasia de la región toracopulmonar es muy poco frecuente y suele presentarse con mayor frecuencia en la población pediátrica. Objetivo. Describir algunas características de pacientes con Tumor de Askin de la Fundación Hospital La Misericordia. Materiales y métodos. Se realizó un análisis retrospectivo de los casos atendidos en una sola institución, Fundación Hospital de la Misericordia, en un lapso de 16 años. Resultados. Se encontraron 8 pacientes, 7 varones, 4 con metástasis al diagnóstico, 2 en pulmón y 2 en hueso, a 2 se les hizo resección quirúrgica completa del tumor al diagnóstico, los demás pacientes fueron llevados a biopsia y quimioterapia citoreductora previa a la cirugía para resección tumoral. Todos recibieron quimioterapia con protocolos para Sarcoma de Ewing y radioterapia en 6 casos. A la fecha están vivos 5 pacientes (62%) con una mediana de seguimiento de 32 meses; 3 de ellos tenían metástasis en el diagnóstico. De los 3 pacientes muertos, 2 no tenían metástasis en el diagnóstico, ambos recayeron y fallecieron por progresión de enfermedad; el otro abandonó el tratamiento a los 6 meses del diagnóstico. Dos pacientes en recaída recibieron quimioterapia de 2 líneas a altas dosis con rescate autólogo, uno está vivo y el otro falleció por progresión de la enfermedad. Conclusión. Se describieron las características clínicas, de laboratorio, diagnóstico, tratamiento y pronóstico de este grupo de pacientes.

Summary Background. The primitive neuroectodermal tumor (TNEP) of the chest wall, or Askin tumor, is a malignant neoplasia classified within the Ewing family of tumours (FSE). This particular type of malignancy of the chest wall is rare and usually appears in the pediatric population. Objective. Describe some characteristics of patients with Askin tumor of the Fundacion Hospital de La Misericordia. Materials and methods. A retrospective analysis of cases treated at a single institution, Fundación Hospital de la Misericordia, in a 16 years period was performed. Results. 8 patients were found, 7 boys, 4 with metastases at the diagnosis, 2 in lungs and 2 in bone, 2 underwent surgery at diagnosis. For the other 6 patients surgical resection was done after chemotherapy. All patients received chemotherapy and 6 received radiotherapy. To date, 5 patients are alive (62 %) with a median follow up of 32 months; 3 of them had metastases at diagnosis. 3 patients died, 2 of which had no metastases in the diagnosis, both relapsed and died of disease progression, the other abandoned treatment at 6 months after diagnosis. Other 2 patients that relapsed received chemotherapy plus autologous transplant, one is alive and the other one died due to disease progression. Conclusion. Clinical, laboratory, diagnosis, treatment and prognosis characteristics of this patient group were described.