[Cytogenetics of myelodysplastic syndromes and its impact as prognostic factor]. / La citogenética de los síndromes mielodisplásicos y su impacto como factor pronóstico.

Myelodysplastic syndromes (MDS) are a group of disorders of the hematopoietic stem cell. They are characterized by cytopenia(s), dysplasia of one or more cell lines, ineffective hematopoiesis, and an increased risk for developing acute myelogenous leukemia. The classification of MDS has been complicated due to the great heterogeneity in clinical phenotype as well as in the morphological and cytogenetic characteristics. The prognostic value of cytogenetic abnormalities in MDS has been analyzed in multicenter studies. This approach raised the development of the revised International Prognostic Scoring System (IPSS-R), which analyzes five prognostic variables, among which the cytogenetic study stands out. According to the cytogenetic findings, a classification of MDS in five subgroups was developed. Knowledge of the cytogenetic abnormalities has led to the study of genes involved in various chromosomal rearrangements. Moreover, DNA sequencing has helped to identify mutations in approximately 50 genes related to signal transduction, DNA methylation, transcriptional regulation, and RNA splicing. Therefore, the cytogenetic study should be used to improve the classification and therapeutic management of MDS. This approach will be an essential tool for the development of targeted therapy protocols.

Los síndromes mielodisplásicos (SMD) son un grupo de alteraciones que involucran a las células madre hematopoyéticas, caracterizadas por citopenia(s), displasia en una o más líneas celulares, hematopoyesis ineficaz y riesgo mayor para desarrollar leucemia aguda mieloblástica. Su clasificación es complicada debido a la heterogeneidad citogenética que condiciona un fenotipo morfológico y clínico también variable. El valor pronóstico de las alteraciones citogenéticas ha sido analizado en estudios multicéntricos y culminó con el desarrollo del Sistema Internacional Revisado de Puntaje Pronóstico (IPSS-R), que analiza cinco variables pronósticas, entre las que destaca el estudio citogenético. Este estudio ha identificado cinco categorías con valor pronóstico: muy bueno, bueno, intermedio, malo y muy malo. El conocimiento de tales alteraciones ha conducido al estudio de genes involucrados en los distintos arreglos cromosómicos, habiendo identificado mutaciones en cerca de 50 genes, mismos que están relacionados con la transducción de señales, la metilación del ácido desoxirribonucleico (ADN), la regulación de la transcripción y con el proceso de corte y empalme del ARN. Actualmente el estudio citogenético es el estándar de oro para el correcto estudio y clasificación de los SMD.

Proteins related to the spindle and checkpoint mitotic emphasize the different pathogenesis of hypoplastic MDS.

Some studies show that alterations in expression of proteins related to mitotic spindle (AURORAS KINASE A and B) and mitotic checkpoint (CDC20 and MAD2L1) are involved in chromosomal instability and tumor progression in various solid and hematologic malignancies. This study aimed to evaluate these genes in MDS patients. The cytogenetics analysis was carried out by G-banding, AURKA and AURKB amplification was performed using FISH, and AURKA, AURKB, CDC20 and MAD2L1 gene expression was performed by qRT-PCR in 61 samples of bone marrow from MDS patients. AURKA gene amplification was observed in 10% of the cases, which also showed higher expression levels than the control group (p=0.038). Patients with normo/hypercellular BM presented significantly higher expression levels than hypocellular BM patients, but normo and hypercellular BM groups did not differ. After logistic regression analysis, our results showed that HIGH expression levels were associated with increased risk of developing normo/hypercellular MDS. It also indicated that age is associated with AURKA, CDC20 and MAD2L1 HIGH expression levels. The distinct expression of hypocellular patients emphasizes the prognostic importance of cellularity to MDS. The amplification/high expression of AURKA suggests that the increased expression of this gene may be related to the pathogenesis of disease.

Epigenetic alterations of p15(INK4B) and p16(INK4A) genes in pediatric primary myelodysplastic syndrome.

We studied the methylation status of the p15(INK4B) and p16(INK4A) genes in 47 pediatric patients with primary MDS, its correlation with subtype, and the role of p15(INK4B) and p16(INK4A) in the evolution of MDS toward AML. Aberrant methylation of the p15(INK4B) gene was detected in 15 of 47 patients (32%), whereas only four patients demonstrated methylation of the p16(INK4A) gene (8%). The frequency of p15(INK4B) methylation was significantly higher in RAEB and RAEB-t subtypes (p<0.003). Aberrant methylation of the p16(INK4A) gene was also more frequent in the subtypes that characterize advanced stages of the disease (p<0.05). Evolution of disease was verified in 17 (36%) of the 47 patients. The association of p15(INK4B) and p16(INK4A) methylation status with evolution of disease was clearly significant (p<0.008 and p<0.05, respectively). These results suggest that methylation of the p15(INK4B) and p16(INK4A) genes is an epigenetic biomarker of pediatric disease evolution.

Mielodisplasia en pacientes pediátricos: evaluación de clasificaciones actuales / Myelodysplasia in pediatric patients: evaluation of current classifications

Introduction: Myelodysplastic Syndrome (MDS) in pediatrics is a rare and difficult clinical picture to diagnose. Classifications currently in use do not always help in identifying risk factors for leukemic transformation in children. Objective: To evaluate the value of current classifications by simultaneously determining a) the frequency of MDS in a pediatric population b) applying CCC classification (category, cytopenias, cytogenetic) and Passmore score (risk score), and c) correlating with progression and evolution to leukemia. Methods: Medical records of 56 children with cytopenias who were registered at the Hemato-oncology Unit, Hospital Roberto del Rio, were retrospectively reviewed from July 2000 to December 2007. Results: 13 patients met MDS diagnostic criteria (7.3 percent of the total hematological malignancies population). According to CCC classification, de novo MDS, refractory cytopenias with dysplasia and abnormal karyotype were the most frequent features. All patients with a high Passmore score progressed to leukemia. Conclusions: SMD classification in pediatrics patients remains difficult given the many differences with an adult population. CCC appears to be the most applicable for our pediatric population. High Passmore score correlated with leukemia development.

Introducción: El Síndrome mielodisplásico (SMD) en pediatría constituye una patología hemato-oncológica rara y de difícil diagnóstico. Las clasificaciones en uso, FAB (Franco Américo Británica) y OMS (Organización Mundial de la Salud), no han permitido definir factores de riesgo de transformación leucémica. Objetivo: Conocer la frecuencia del SMD en una población pediátrica, aplicar la clasificación CCC (Categoría, Citopenia, Citogenética) y el Score de Passmore (puntaje de riesgo) y relacionarlos con evolución y progresión a leucemia. Pacientes y Método: Revisión retrospectiva de 56 fichas de pacientes con citopenias atendidos en la Unidad de Hemato-oncología del Hospital Roberto del Río, entre Julio 2000 y Diciembre 2007. Resultados: Trece pacientes reunían criterios de SMD, correspondiendo al 7,3 por ciento de las neoplasias hematológicas. Al aplicar la clasificación CCC, predominaron los SMD de novo, las citopenias refractarias con displasia y el cariotipo anormal. Todos los pacientes con Score de Passmore > 2 progresaron a leucemia (4/9). Conclusiones: La clasificación del SMD en pediatría continúa siendo compleja. La clasificación CCC resultó más aplicable en la población pediátrica que las anteriores clasificaciones. El Score de Passmore mostró una alta correlación entre puntaje elevado y evolución a leucemia.

Síndromes mielodisplásicas: aspectos moleculares, laboratoriais e a classificação OMS 2008 / Myelodysplasic symdrome: molecular and laboratorial aspects and the 2008 WHO classification

As síndromes mielodisplásicas (SMDs) são caracterizadas por uma desordem clonal de células primordiais (stem cell) e hematopoese ineficaz que levam à displasia de uma ou mais linhagens celulares da medula óssea, citopenias periféricas e instabilidade genética, as quais aumentam o risco de transformação à leucemia mieloide aguda. Esse grupo heterogêneo de doenças hematopoéticas pode surgir como doença primária, que possui etiologia variada e não completamente definida, ou secundária ao tratamento quimioterápico ou radioterápico para outras neoplasias. O surgimento e aprimoramento de tecnologias de diagnóstico geraram uma melhor compreensão dos processos envolvidos na gênese e evolução das SMDs, o que possibilitou o desenvolvimento de marcadores de diagnóstico e acompanhamentos cada vez mais precoces e específicos. No ano de 2008, a Organização Mundial da Saúde (OMS) redefiniu os critérios para classificação das SMDs, dividindo-as em sete subgrupos. Nessa classificação foram incluídos novos aspectos imunofenotípicos, genéticos, citomorfológicos e moleculares, o que tornou o domínio e o acesso a tecnologias de ponta imprescindíveis para a realização do diagnóstico das SMDs. Apesar dos avanços tecnológicos, alguns pontos, como as bases moleculares da transformação de SMD para LMA, ainda não estão bem esclarecidos, fazendo necessária a continuação de estudos nessa área. Diante disso, essa revisão busca compilar dados atuais dos aspectos moleculares e laboratoriais das SMDs.

Myelodysplastic syndromes (MDSs) are characterized by a stem cell clonal disorder and ineffective hematopoiesis which causes dysplasia in one or more bone marrow hematopoietic cell lineages, peripheral cytopenia and genetic instability with enhanced risk to transform into acute myeloid leukemia (AML). This heterogeneous group of hematopoietic diseases can develop as primary diseases, which posses a variable and not completely defined etiology, or as secondary to chemotherapy or radiotherapy for other neoplasias. The evolution of diagnostic tests has improved comprehension of the process involved in the genesis and evolution of MDSs, making the development of earlier and more specific tests for diagnosis and follow ups possible. In 2008, the World Health Organization (WHO) redefined the criteria for the classification of MDSs, dividing them into seven subgroups. This classification included new immunophenotypic, genetic, cytomorphologic and molecular features, which are essential for the diagnosis of MDSs and for a better comprehension of the disease. Despite technological advances, some details, such as the molecular basis of the transformation of MDS to AML, are still not completely understood, which makes further studies in this field necessary. Hence, the objective of this review is to make a compilation of recent molecular and laboratory aspects of MDS.

Classificações morfológicas das síndromes mielodisplásicas: da classificação Franco-Americana-Britânica (FAB) à classificação da Organização Mundial da Saúde (OMS) / Morphologic classifications of myelodysplastic syndromes: from FAB to WHO

A classificação inicial das síndromes mielodisplásicas (SMD) foi realizada em 1976, pelo grupo FAB, e era baseada em parâmetros morfológicos observados no sangue periférico e na medula óssea. A classificação FAB foi revisada em 1982 e utilizada nos últimos 25 anos como guia para melhor compreensão desse heterogêneo grupo de doenças. Em 2001, a OMS publicou uma nova classificação, com modificações significativas nos diversos subgrupos da FAB, com o intuito de agrupar melhor subtipos com comportamento clínico semelhante. A mudança mais importante foi a diminuição do número mínimo de blastos para o diagnóstico de LMA de 30 por cento para 20 por cento, causando o desaparecimento do subtipo AREB-T. Esta é também a mudança mais polêmica, havendo inúmeras publicações discutindo as evidentes diferenças clínicas e biológicas entre SMD e LMA, sendo unânime a opinião de que apenas o número de blastos é insuficiente para a escolha da terapêutica. Outro ponto importante foi a diferenciação de grupos com displasia em única e em múltiplas linhagens, que mostra ter grande importância para o prognóstico. Diversos estudos têm sido publicados, comparando as classificações FAB e OMS, reconhecendo a grande contribuição da classificação FAB para a melhor compreensão das SMD, bem como suas falhas e tentando validar as mudanças propostas pela classificação da OMS e identificar pontos passíveis de modificação.

The initial classification of the myelodisplastic syndromes (MDS) was compiled in 1976 by the FAB group and was based on morphological parameters observed in the peripheral blood and in the bone marrow. The FAB classification was revised in 1982 and has been used in the last 25 years as a guide for a better understanding of this heterogeneous group of diseases. In 2001, the WHO published a new classification with significant modifications in the diverse subgroups of FAB with the intention of obtaining a better grouping of the subtypes with similar clinical behaviors. The most important modification was the decrease in the minimum number of blasts for the AML diagnosis from 30 percent to 20 percent, resulting in the disappearance of the subtype RAEB-T. This is also the most polemic alteration, as there are innumerable publications discussing the evident clinical and biological differences between the MDS and AML, with the opinion that the number of blasts alone is insufficient for the choice of therapy being unanimous. Another important point was the differentiation of the groups with dysplasia in single and multiple strains, which has been demonstrated as having great importance in the prognosis. Several studies have been published comparing the FAB and WHO classifications, recognizing the great contribution of the FAB classification for the better understanding of the MDS, as well as its shortcomings, and attempting to validate the modifications proposed by the WHO classification and identify the points liable to modification.

Síndromes mielodisplásticos en pediatría / Pediatric myelodysplastic syndromes

Los síndromes mielodisplásticos (SMD) son desórdenes clónales de las células madres hematopoyéticas caracterizados por hematopoyesis inefectiva, citopenia periférica y riesgo variable de transformación a leucemia mieloide aguda (LMA). Los SMD son relativamente raros en niños, representando aproximadamente el 3 por ciento de las neoplasias hematológicas pediátricas. Se han descrito numerosos subtipos de SMD en niños, no existiendo actualmente una clasificación de consenso. Existen desórdenes genéticos que predisponen al desarrollo de SMD en niños, como el síndrome de Down, la neurofibromatosis tipo I y síndrome de falla medular hereditarios; por otro lado, la exposición a agentes quimioterapéuticos y radiaciones ionizantes, aumenta el riesgo de desarrollar SMD tanto en niños como en adultos. Los SMD infantiles usualmente tienen un curso clínico agresivo y son de difícil manejo, siendo el trasplante de médula ósea alogénico el único tratamiento curativo conocido actualmente.

Trasplante de células progenitoras hematopoyéticas en síndromes mielodisplásicos / Hematopoietic stem cell transplantation in the myelodisplastic syndromes

Myelodisplastic syndromes (MDS) are clonal hematopoietic disorders, characterized by ineffective hemopoiesis resulting in single or multiple lineages and a high risk of conversion to acute leukemia. Currently, the only established therapy with curative potential for MDS is a hemopoietic stem cell transplant (HSCT). Their results are determined by the type of MDS, age at the BMT and the score according to the international index. In the main studies the disease-free survival (DFS) were 35-43%, relapse 20 to 39% and transplantation-related mortality (TRM) 36-45%. HSCT offers best results in goods prognosis MDS (refractory anemia, refractory anemia with ring sideroblasts) with DFS of 53-72% and 13% of relapse, in contrast with the advanced MDS (refractory anemia with blast in excess (AREB), AREB in transformation and secondary acute leukemia) where the DFS is about ~ 33%, the relapse 23-34% and MRT 37-60%. The HSCT from unrelated donor is an option for patients that do not an HLA-matched related donor, with a ~ 30% of DFS, but with a MRT up to 58%. The HSCT with regimens of low intensity (minitransplants) for aged patients are feasible but their efficacy has not yet been determined.

Los síndromes mielodisplásicos (SMD) constituyen un grupo de enfermedades de las células progenitoras hematopoyéticas (CPH) caracterizadas por hematopoyesis ineficaz y una tendencia elevada a evolucionar a leucemia aguda. Hasta el momento actual el único tratamiento curativo lo representa el trasplante de CPH. Los resultados con esta terapia dependen de la variedad del SMD, de la edad de los pacientes al momento del trasplante y del índice pronóstico internacional. Los resultados de las principales series muestran una supervivencia libre de enfermedad (SLE) de 35-43%, con una recaída de 20 a 39% y una mortalidad asociada al trasplante (MRT) de 36 a 45%. Los mejores resultados se obtienen en SMD de buen pronóstico (anemia refractaria/anemia refractaria con sideroblastos en anillo) con SLE de 53-72% y una frecuencia de recaída de 13%, en contraste con los SMD avanzados (anemia refractaria con exceso de blastos ]AREB], AREB en transformación y leucemia aguda secundaria) en los que la SLE es de ~ 33%, la recaída de 23-34% y la MRT de 37-60%. El trasplante de CPH con donador vivo no relacionado es una opción para los pacientes que carecen de un donador familiar, con SLE de ~ 30% pero con una elevada MRT que llega a ser hasta de 58%. Los trasplantes con acondicionamiento de intensidad reducida (minitrasplantes) son factibles de realizar en pacientes de edad avanzada, aunque su eficacia está aún por determinarse.

[Hematopoietic stem cell transplantation in the myelodisplastic syndromes]. / Trasplante de células progenitoras hematopoyéticas en síndromes mielodisplásicos.

Myelodisplastic syndromes (MDS) are clonal hematopoietic disorders, characterized by ineffective hemopoiesis resulting in single or multiple lineages and a high risk of conversion to acute leukemia. Currently, the only established therapy with curative potential for MDS is a hemopoietic stem cell transplant (HSCT). Their results are determined by the type of MDS, age at the BMT and the score according to the international index. In the main studies the disease-free survival (DFS) were 35-43%, relapse 20 to 39% and transplantation-related mortality (TRM) 36-45%. HSCT offers best results in goods prognosis MDS (refractory anemia, refractory anemia with ring sideroblasts) with DFS of 53-72% and 13% of relapse, in contrast with the advanced MDS (refractory anemia with blast in excess (AREB), AREB in transformation and secondary acute leukemia) where the DFS is about approximately 33%, the relapse 23-34% and MRT 37-60%. The HSCT from unrelated donor is an option for patients that do not an HLA-matched related donor, with a approximately 30% of DFS, but with a MRT up to 58%. The HSCT with regimens of low intensity (minitransplants) for aged patients are feasible but their efficacy has not yet been determined.

Clasificaciones y sistemas pronósticos en síndromes mielodisplásicos / Classification and prognostic systems in myelodysplastic syndromes

Myelodysplastic syndrome (MDS) comprises a group of heterogeneous hematological disorders with risk of leukaemic evolution (LE), characterized by varied degrees of peripheral cytopenias related to a progressive bone marrow (BM) failure. Due to the heterogeneity of this pathology and the difficulty to make decisions regarding therapy, different classification and prognostic systems have been developed. The French-AmericanBritish cooperative group defined the first criterion for a systematic classification in 1982 that recognized morphologic entities: refractory anemia (RA), RA with ringed sideroblasts (RARS), RA with excess of blast (RAEB), RAEB in transformation (RAEBt) and chronic myelomonocytic leukemia (CMML). Although the FAB is the classification with major agreement, it has some prognostic failures. Therefore, since 1985 different instruments-scoring systems for prognosis were developed taking into account diverse clinical parameters including the cytogenetic analysis in 1993. In order to standardize prognostic features in MDS the International Scoring System (IPSS) was generated in 1997. This score defined risk groups for survival and LE on the basis of percentage of BM myeloblasts, cytogenetic abnormalities and number of cytopenias. Finally in 1999, the World Health Organization proposed a new classification system based on morphology and cytogenetic findings making another intent to sort out the heterogeneity of this pathology

Los síndromes mielodisplásicos comprenden un grupo heterogéneo de trastornos ematológicos caracterizados por grados variables de citopenias periféricas relacionadas con una falla medular progresiva con riesgo de evolución leucémica. Dada la heterogeneidad de la patología y la dificultad de aplicar una terapéutica eficaz, se han publicado diversos sistemas de clasificación y pronóstico. El primer criterio de clasificación sistemática fue definido en 1982 por el Grupo Cooperativo FrancoAmericano-Británico (FAB) reconociendo entidades morfológicas: anemia refractaria (AR), AR con sideroblastos anillados (ARSA), AR con exceso de blastos (AREB), AREB en transformación (AREBt), y leucemia mielomonocítica crónica (LMMC). Aunque es la clasificación de mayor reconocimiento internacional, posee ciertas falencias pronósticas. Consecuentemente, desde 1985 se registran diferentes sistemas de predicción que toman en cuenta ciertas variables clínicas e incorporan, en 1993, el estudio citogenético. Finalmente, en 1997 se genera el Sistema Pronóstico Internacional (IPSS), el cual discrimina grupos de riesgo para supervivencia y evolución leucémica teniendo en cuenta el porcentaje de blastos en médula ósea, el cariotipo y las citopenias periféricas. El último abordaje sugerido por la Organización Mundial de la Salud, en 1999, propone un nuevo sistema de clasificación basado en hallazgos morfológicos y citogenéticos para entender esta compleja patología.

Detección de grupos de riesgo en síndromes mielodisplásicos. Un estudio multicéntrico / Detection of risk groups in myelodisplastic syndromes. A multicentric study

Los síndromes mielodisplásicos (SMD) comprenden un grupo heterogéneo de desordenes hematólogicos con riesgo de evolución a leucemia mieloide aguda (LMA). El Grupo Franco-Americano-Británico (FAB) los clasifica en cinco entidades morfológicas y el Sistema Pronóstico Internacional (IPSS) propone cuatro grupos de riesgo basándose en variables clínicas y citogenéticas. El objetivo del trabajo fue evaluar la aplicación del IPSS en población Argentina, analizar el valor pronóstico de sus variables y determinar si dicho sistema permite identificar subgrupos pronósticos de riesgo dentro de los subtipos FAB. Se evaluaron 234 pacientes con SMD de novo (Media de seguimiento: 28 meses), con el fin de determinar sobrevida (SV) y sobrevida libre de LMA (SLL). Se analizaron la clasificación FAB y el IPSS, así como sus variables (número de citopenias, porcentaje de blastos, grupos de riesgo citogenético). Los resultados mostraron diferencias significativas para SV y SLL. La aplicación del IPSS permitió la diferenciación de los cuatro grupos de riesgo y ayudó a identificar subclases pronósticas dentro de los subtipos FAB: 5 , 15 y 19 por ciento de pacientes con peor pronóstico dentro de los subtipos Anemia Refractaria (AR), AR con sideroblastos en anillo (ARSA) y AR con exceso de blastos (AREB), respectivamente. El IPSS no fue informativo para el subtipo AREB en transformación, ni tampoco en pacientes con leucemia mielomonocítica crónica.

Síndromes mielodisplásicas: revisão dos esquemas de classificação / Myelodysplastic syndromes: classification schemes review

Introdução: As síndromes mielodisplásicas (SMD) são doenças clonais das células-tronco hematopoiéticas caracterizadas por hematopoiese ineficiente e freqüente evolução para leucemia mielóide aguda. Em 1982, o Grupo Franco-Americano-Britânico (FAB) propôs classificação para as SMD, baseada em características morfológicas no sangue periférico e medula óssea. Recentemente a organização Mundial de Saúde (OMS) publicou uma classificação revisada das SMD, baseada em modificações significantes da proposta FAB. Objetivo: Enfocar as principais diferenças entre os dois esquemas referidos de classificação. Método: Material pesquisado no banco de dados da Biblioteca Nacional de Medicina e do Centro Nacional para Informação em Biotecnologia dos Estados Unidos, com os termos: "síndromes "mielodisplásicas", "câncer", "classificação", "prognóstico", "revisão", "FAB", "OMS". Foram selecionados apenas artigos publicados em in-ês entre 1976 e 2004. Considerações Finais: A classificação da OMS das SMD foi construí da a partir do bem sucedido esquema FAB, da qual clínicos e patologistas estão familiarizados, e suas mudanças incluem dados citogenéticos e o refinamento dos critérios de diagnóstico. Contudo, como todos os esquemas de classificação, proposta da OMS deve ser considerada um trabalho em progressão e, à medida que forem acumuladas evidências sobre o significado de lesões genéticas específicas e características clínicas, revisões serão necessárias

Factors influencing survival in myelodysplastic syndromes in a Brazilian population: comparison of FAB and WHO classifications.

The WHO classification for myelodysplastic syndromes (MDS) has introduced new categories with prognostic relevance. Our aim was to examine the predictive value of the WHO and the FAB classification compared to parameters of peripheral blood, bone marrow and IPSS. Clinical data, peripheral blood counts, bone marrow (BM) cytology and histology and survival were analyzed in consecutive newly diagnosed adult patients with MDS. All cases were diagnosed according to FAB criteria and reclassified by the WHO proposal. Among 150 patients entering the study median age was 58 years (12-90). According to FAB, 90 patients had refractory anemia (RA), 18 sideroblastic anemia, 34 refractory anemia with excess of blasts (RAEB), three RAEB-t and five chronic myelomonocytic leukemia. Using the WHO proposal, one half of the patients with RA changed category. One patient had the 5q-syndrome. There were 25 cases with refractory cytopenias with multilineage dysplasia (RCMD) and 23 WHO "unclassified". These last patients presented few cell atypias, favorable IPSS and a good survival as has been described for refractory cytopenias in pediatric MDS. Hypocellular BM was found in 24% of the patients. Karyotype was available in only 85 cases. In the univariate analysis, both classifications, hemoglobin values, hypercellular bone marrow and IPSS had an influence on survival. Using the bootstrap resampling as stability test for the model created by the multivariate analysis, the WHO classification entered the model in 73%, FAB in 38% and IPSS in only 7%. Therefore, in a setting with a high number of low-risk MDS, the WHO classification is the best predictor of survival of the patients.

Myelodysplastic syndrome in childhood: report of two cases with deletion of chromosome 4 and the Philadelphia chromosome.

We report two pediatric patients with unclassified myelodysplastic syndrome (MDS) by the French-American-British (FAB) group. Both cases had clinical and hematological peculiarities, which had not been described yet. The cytogenetic alterations were 4q deletion and the Philadelphia (Ph) chromosome which appeared at different moments of the disease. One patient showed the Ph chromosome at disease transformation and the other at diagnosis. The different breakpoints at 4q and the presence of Ph could be a marker of this form of MDS. The association of clinical and hematological findings suggests the possibility of a new group of pediatric MDS.

Detection of risk groups in myelodysplastic syndromes. A multicenter study.

BACKGROUND AND OBJECTIVES: Myelodysplastic syndromes (MDS) comprise a group of heterogeneous hematologic disorders with risk of leukemic evolution (LE). The French-American-British (FAB) co-operative group classifies them into five morphologic entities and the International Prognostic Scoring System (IPSS) proposes four groups of risk on the basis of clinical and cytogenetic variables. The aim of this study was to evaluate the application of the IPSS in our Argentine population, to test the prognostic value of its variables and to determine whether this score helps to associate prognostic subgroups of risk into FAB subtypes. DESIGN AND METHODS: Two hundred and thirty-four patients with primary MDS and a median follow-up of 28 months were evaluated using univariate analyses to determine median survival (SV) and the time to LE. The variables analyzed were FAB classification, IPSS, percentage of myeloblasts, cytogenetic groups of risk and number of cytopenias. RESULTS: Univariate analyses showed that all variables analyzed were predictive for SV and for LE in our MDS population. Application of the IPSS allowed discrimination into the 4 groups of risk and helped to identify prognostic subclasses among the FAB classification, associating 5%, 15% and 19% of cases with worse prognosis within the FAB classification of refractory anemia (RA), RA with ringed sideroblasts and RA with excess of blasts (RAEB), respectively. The IPSS was not informative for RAEB in transformation cases and would not be applied to patients with chronic myelomonocytic leukemia. INTERPRETATION AND CONCLUSIONS: This score could be applied to our MDS population, showing no geographic differences. Stratification of FAB patients according to IPSS would be helpful to develop risk-adapted therapeutic strategies.

Estudo citogenético em síndrome mielodisplásica na infância / Cytogenetic study in myelodysplastica syndrome in childhood

A classificação, alterações citogenéticas e as peculiaridades da síndrome mielodisplásica na criança são apresentadas neste trabalho. Aspectos do tratamento aqui são comparados aos das síndromes mielodisplásicas nos adultos.

The classification, cytogenetic alterations and peculiarities of mielodisplastic syndrome in childhood are presented in this work, along with aspects of treatment in infancy compared withthose used in adults.

Síndrome mielodisplástico en pediatría: experiencia clínica / Myelodysplastic syndrome in children: clinical experience

Objetivo: describir los hallazgos clínicos y la evolución en niños con síndrome mielodisplástico y sugerir conductas de manejo de esta infrecuente enfermedad. Pacientes y método: revisión retrospectiva de 17 casos de mielodisplasia atendidos en el Hospital Roberto dl Río entre 1981 y 1997. De acuerdo a la clasificación FAB fueron catalogados como anemia refractaria 7 pacientes, 3 como anemia refractaria con exceso de blastos, 2 correspondieron a anemia refractaria con exceso de blastos en transformación, 4 a leucemia mielomonocítica crónica y un niño con síndrome de Down y anemia refractaria con exceso de blastos. Resultados: 10 pacientes eran hombres, edad de presentación entre 1 año 7 meses y 14 años, la mayoría con pancitopenia periférica y médula hipercelular, 2 presentaron trisomía 8 en el estudio citogénico y los niños con leucemia mielomonocítica crónica tuvieron hepatoesplenomegalia y hemoglobina fetal elevada. El tratamiento fue de soporte y quimioterapia. 8 pacientes evolucionaron a leucemia aguda, 5 a mieloide y 3 a linfoblástica, en una mediana de 8 meses. 8 niños están vivos con una mediana de observación de 72 meses. Conclusiones: esta experiencia confirma la heterogeneidad de esta enfermedad en su presentación y evolución clínica y sugiere la conducta actual en el enfrentamiento y manejo

Childhood myelodysplastic syndromes in a Brazilian population.

Fourteen pediatric cases of myelodysplastic syndrome according to French-American-British Co-operative Group (FAB) criteria were identified in a retrospective review of all cases of hematologic malignancies referred to the Pediatric Oncology division of the Cancer Hospital A. C. Camargo over a 12-year period: 1 case of refractory anemia, 8 cases of refractory anemia with excess of blasts, and 1 case of refractory anemia with excess of blasts in transformation. Three children had features consistent with chronic myelomonocytic leukemia, and one child was diagnosed with secondary myelodysplastic syndrome. The median age was 3.5 years (1 month-11 years). In 11/14 cases the disease evolved to acute leukemia. In 3 patients blasts had morphological and cytochemical features of lymphoblasts. Two of these patients had a good response to acute lymphoblastic leukemia chemotherapy protocol. The time of progression to leukemia in these cases was shorter than in those who evolved to acute myeloid leukemia. The authors believe this to be the first series of pediatric myelodysplastic syndrome documented in Brazil. Cases were characterized by aggressive FAB type, conspicuous cell atypias in all 3 hemopioetic cell lines, and a high rate of evolution to acute leukemia.