Systematic Classification of Mixed-Lineage Leukemia Fusion Partners Predicts Additional Cancer Pathways

Chromosomal translocations of the human mixed-lineage leukemia (MLL) gene have been analyzed for more than 20 yr at the molecular level. So far, we have collected about 80 direct MLL fusions (MLL-X alleles) and about 120 reciprocal MLL fusions (X-MLL alleles). The reason for the higher amount of reciprocal MLL fusions is that the excess is caused by 3-way translocations with known direct fusion partners. This review is aiming to propose a solution for an obvious problem, namely why so many and completely different MLL fusion alleles are always leading to the same leukemia phenotypes (ALL, AML, or MLL). This review is aiming to explain the molecular consequences of MLL translocations, and secondly, the contribution of the different fusion partners. A new hypothesis will be posed that can be used for future research, aiming to find new avenues for the treatment of this particular leukemia entity.

Pattern of Leukaemias in a Tertiary Care Hospital - A 5 Years Retrospective Study of 103 Cases.

Objective: To study the distribution of various types of leukaemia in the RIMS Hospital in terms of types, age, sex and among various ethnic groups. Material and Method: It’s a retrospective study carried out in the department of Pathology, Regional Institute of Medical Sciences (RIMS) Hospital over a five years period between November 2006 and October 2011. Diagnosis was based on peripheral blood count, peripheral blood smear and bone marrow examination for morphology along with cytochemistry study whenever required. FAB classification is followed in the study. SPSS software package, version 16, was used for statistical analysis. Result: Out of total 103 cases, 49cases (47.6%) were children and adolescents and 54 cases (52.4%) were adults. Age range was 9 months to 79 years with a mean age of 31.2 years. Among the children and adolescents, 30 cases were males and 18 cases were females (M: F ratio 1.7:1). In the adults 34 cases were males and 21 cases were females with M: F ratio 1.6:1. Overall male female ratios was 1.6:1. Out of 103 cases, 85.4% were of of acute leukaemia and rest were chronic leukaemia (14.6%). Acute leukaemia was the most common leukaemia in all age groups. Of all leukaemia cases reported, maximum cases were of acute myeloid leukaemia (AML). Acute lymphoblastic leukaemia (ALL) is the most common type of leukaemia in the children (60.7%) and adolescents (52.3%). AML (66.7%) is the most common acute leukaemia in adults. Among ALL, L2 is the most common variant (82.3%) and in AML, M3 is the most common (38.8%). Chronic leukaemia was more common in adult (80%) than children and adolescents. Out of total 12 cases of the chronic leukaemia reported in adults, 10 were of chronic myeloid leukaemia (CML), 2 were chronic lymphocytic leukaemia (CLL). The maximum cases of leukaemia were among Meitei community (64%) followed by tribal community (28%) and minimum in Muslims (8%). Conclusion: In this study, acute leukaemia was the most common leukaemia in all age groups. Of all leukaemia cases reported, maximum cases were of AML and minimum cases were of CLL. Chronic leukaemia was more common in adult. In children, majority of cases were ALL and chronic leukaemia was rare. Leukaemias were more common in males. Meitei community was affected the most.

Classificação dos tumores hematopoéticos e linfoides de acordo com a OMS: padronização da nomenclatura em língua portuguesa, 4ª edição / Classification of haematopoietic and lymphoid tumors: WHO, standardization of nomenclature in Portuguese, 4th edition

INTRODUÇÃO: A classificação da Organização Mundial da Saúde (OMS) para os tumores do tecido hematopoético e linfoide (4ª edição, 2008) representa uma revisão atualização da 3ª edição publicada em 2001. A tradução da nomenclatura utilizada para identificar as entidades descritas deve ser clara, precisa e uniforme no sentido de reproduzir de forma correta as diversas entidades clinicopatológicas para clínicos, patologistas e pesquisadores envolvidos na área da onco-hematopatologia. OBJETIVO: Os autores apresentam uma proposta de atualização e padronização terminológica em língua portuguesa, com base na OMS/2008.

INTRODUCTION: The World Health Organization (WHO) classification of hematopoietic and lymphoid tissue (4th edition, 2008) tumors constitutes an updated review of the 3rd edition published in 2001. The translation of the nomenclature used to describe the entities should be clear, precise and uniform so that clinicians, pathologists and researchers involved in the onco-hematopathological area may identify them accurately. OBJECTIVE: With this purpose, the authors present an updated proposal and a terminological standardization in Portuguese based on WHO/2008.

Immunophenotypic characterization of acute leukemia at a public oncology reference center in Maranhão, northeastern Brazil / Caracterização imunofenotípica das leucemias agudas em um centro oncológico de referência público no Maranhão, Nordeste do Brasil

CONTEXT AND OBJECTIVES: The incidence of acute leukemia (AL) subtypes varies according to geographical distribution. The aim here was to determine the incidence of morphological and immunophenotypic AL subtypes in the state of Maranhão, Brazil, and to correlate the expression of aberrant phenotypes in children with acute lymphoblastic leukemia (ALL) with prognostic factors. DESIGN AND SETTING: Single prospective cohort study at a public oncology reference center in Maranhão. METHODS: Seventy AL cases were diagnosed between September 2008 and January 2010. For the diagnosis, complete blood cell counts, myelograms (at diagnosis and at the end of the induction phase), cytochemical analysis and immunophenotyping were performed. RESULTS: Among adult patients (n = 22), the incidence of AL types was: ALL (22.7 percent) and acute myeloid leukemia (AML) (77.3 percent). The subtype AML M0 occurred most frequently (29.4 percent). In children (n = 48), the types were: AML (18.7 percent), most frequently subtype AML M4 (33.4 percent); biphenotypic acute leukemia (BAL) (4.2 percent); and ALL (77.1 percent), including the subtypes B-ALL (72.9 percent) and T-ALL (27.1 percent). Among the children with ALL, there were no statistically significant differences between patients with and without aberrant phenotypes, in relation to hematological parameters and treatment response. CONCLUSION: This work demonstrates that the frequencies of AML M0 cases among adults and T-ALL cases among children in Maranhão were high. This suggests that there may be differences in AML subtype incidence, as seen with ALL subtypes, in different regions of Brazil. No association was found between the expression of aberrant phenotypes and prognostic factors, in children with ALL.

CONTEXTO E OBJETIVOS: A incidência dos subtipos de leucemias agudas (LA) tem mostrado variações em relação à distribuição geográfica. Objetivou-se determinar a incidência dos subtipos morfológicos e imunofenotípicos de LA no estado do Maranhão, Brasil, e relacionar a expressão de fenótipos aberrantes em crianças com leucemia linfoblástica aguda (LLA) com fatores prognósticos. TIPO DE ESTUDO E LOCAL: Estudo de coorte único prospectivo em um centro oncológico de referência público no Maranhão. MÉTODOS: Diagnosticaram-se 70 casos de LA no período de setembro de 2008 a janeiro de 2010. No diagnóstico, realizaram-se hemogramas, mielogramas (no diagnóstico e ao final da fase de indução), citoquímica e imunofenotipagem. RESULTADOS: Nos pacientes adultos (n = 22), as incidências dos tipos de LA foram: LLA (22,7 por cento) e leucemia mieloide aguda (LMA) (77,3 por cento), sendo o subtipo LMA M0 mais frequente (29,4 por cento). Em crianças (n = 48): LMA (18,7 por cento), subtipo LMA M4 mais frequente (33,4 por cento), leucemia bifenotípica aguda (BAL) (4,2 por cento) e LLA (77,1 por cento), sendo os subtipos LLA-B (72,9 por cento) e LLA-T (27,1 por cento). Na LLA, em crianças, não se encontrou diferença estatisticamente significante entre pacientes com e sem fenótipos aberrantes, em relação aos parâmetros hematológicos e resposta ao tratamento. CONCLUSÃO: Esta pesquisa demonstra elevada frequência de casos de LMA M0 em adultos, bem como das LLA-T em crianças no Maranhão, sugerindo que podem haver diferenças na incidência dos subtipos das LMA, assim como dos subtipos de LLA, em diferentes regiões do Brasil. Não foi encontrada associação entre a expres de fenótipos aberrantes e fatores prognósticos em crianças com LLA.

A Study of Mixed Phenotype Acute Leukemia Based on the 2008 World Health Organization Classification / 대한진단검사의학회지

BACKGROUND: We evaluated the clinical significance of revised 2008 WHO classification needed to diagnose mixed phenotype acute leukemia (MPAL). METHODS: A total of 22 MPAL patients, previously diagnosed by applying the scoring system of the European Group for Immunological Classification of Acute Leukemias (EGIL) were reclassified based on the 2008 WHO classification. RESULTS: In 2008 WHO classification, the number of monoclonal antibodies (mAbs) required for assigning more than one lineage was markedly decreased, from 26 to 11, compared with that of EGIL. Seventeen of the 22 MPAL patients were reclassified as MPAL with following details: 6 MPAL with t(9;22)(q34;q11.2); BCR-ABL1, 1 MPAL with t(v;11q23); MLL rearranged, 7 MPAL, B/Myeloid, not otherwise specified (NOS) and 3 MPAL, T/Myeloid, NOS. Five patients were excluded from MPAL in the revised classification: 4 cytoplasmic myeloperoxidase (cMPO)-negative and 1 CD19-negative. The failure of complete remission achievement and occurrence of relapse were associated with poor prognosis (P=0.0002 and P=0.009, respectively). But the presence of Philadelphia chromsome was not significantly related with patient outcome (P=0.082). One patient with cCD79a, CD20, CD38, cMPO and CD15, whose diagnosis was reclassified from MPAL to AML has survived during the study period. CONCLUSIONS: Because of decreased number of mAbs needed, it is possible that acute leukemia panel is designed to include all mAbs required to diagnose MPAL according to 2008 WHO classification. When diagnosing MPAL, it is critical to figure out positivity in either cMPO or CD19, and AML expressing more than 2 lymphoid antigens are considered as MPAL.

Importance of detecting FLT3 and NPM1 gene mutations in acute myeloid leukemia -World Health Organization Classification 2008

As leucemias mieloides agudas (LMA) constituem um grupo de neoplasias malignas caracterizadas pela proliferação descontrolada de células hematopoéticas, decorrente de mutações que podem ocorrer em diferentes fases da diferenciação de células precursoras mieloides. Em 2008, a Organização Mundial da Saúde (OMS-2008) publicou uma nova classificação para neoplasias do sistema hematopoético e linfoide. De acordo com essa classificação, para um diagnóstico mais preciso e estratificação de prognóstico de pacientes com leucemias mieloides agudas, devem-se pesquisar mutações nos genes FLT3 e NPM1. Sabe-se que a presença de mutações no gene FLT3 é de prognóstico desfavorável e que as mutações no gene NPM1 do tipo A são de prognóstico favorável. Assim, nos países desenvolvidos, a análise das mutações no gene FLT3 e NPM1 tem sido considerada como um fator de prognóstico importante na decisão terapêutica em pacientes com diagnóstico de leucemias mieloides agudas. Considerando essas informações, é de extrema importância a análise das mutações no gene FLT3 (duplicação interna em tandem - DIT - e mutação pontual D835) e no gene NPM1 como marcadores moleculares para o diagnóstico, o prognóstico e a monitoração de doença residual mínima em pacientes com leucemias mieloides agudas.

Acute myeloid leukemia (AML) is a group of malignancies characterized by uncontrolled proliferation of hematopoietic cells resulting from mutations that occur at different stages in the differentiation of myeloid precursor cells. In 2008, the World Health Organization (WHO-2008) published a new classification for cancers of the hematopoietic and lymphoid system. According to this classification, FLT3 and NPM1 gene mutations should be investigated for a more precise diagnosis and prognostic stratification of AML patients. It is well known that the presence of FLT3 gene mutations is considered an unfavorable prognostic factor and type-A NPM1 gene mutations are considered to be favorable. In developed countries, an analysis of FLT3 and NPM1 mutations is considered important for therapeutic decisions in AML patients. Hence, an analysis of FLT3 (internal tandem duplication - ITD- and D835 point mutation) and NPM1 gene mutations is extremely important as molecular markers for diagnosis, prognosis and monitoring of minimal residual disease in LMA patients.

Leucemias agudas pediátricas de inmunofenotipo inusual / Childhood acute leukemias of unusual phenotype

La mayoría de las Leucemias Agudas (LA) pediátricas pueden clasificarse como Linfoblásticas (principalmente de fenotipo B o T) o Mieloblásticas dependiendo del linaje celular de los blastos, recibiendo tratamiento específico de acuerdo a esta caracterización. La inmunotipificación de las LA se basa en la evaluación de la expresión de antígenos de superficie y/o intracitoplasmáticos de diferenciación linfoide (B o T) o mieloide (My) en los blastos, lo cual permite definir la estirpe celular y clasificar la LA de acuerdo al grado de maduración. Sin embargo, existen grupos particulares poco frecuentes de LA cuya clasificación resulta dificultosa y por eso se las denomina LA de linaje ambiguo (fenotipo mixto/indiferenciadas) y LA de linaje dendrítico. Las de fenotipo mixto son aquellas en las que los blastos expresan marcadores de más de un linaje, y las indiferenciadas aquellas que no expresan antígenos específicos para ningún linaje. Diferentes convenciones se han ido desarrollando para definir y clasificar estos fenotipos inusuales, siendo la más actualizada la propuesta por la Organización Mundial de la Salud (2008). De acuerdo a estas pautas, de 1301 casos de LA diagnosticados entre abril de 1994 y abril de 2009, 28 fueron re-clasificados como LA de linaje Ambiguo, 3 como leucemia mieloide aguda minimamente diferenciadas y 3 como LA de células dendríticas. Debido a lo infrecuente de estos casos, su caracterización resulta relevante, ya que la bibliografía presenta, en general, sólo comunicaciones esporádicas de estos fenotipos particulares. Dada la importante casuística del Hospital Garrahan y el amplio seguimiento de los pacientes, el relevamiento de estos casos inusuales permite caracterizarlos desde el inmunofenotipo, la morfología/citoquímica, la citogenética/biología molecular y evaluar su presentación clínica, evolución, respuesta al tratamiento y sobrevida libre de eventos con la finalidad de colaborar con la definición de su pronóstico y eventualmente con la elaboración de protocolos de tratamiento diferenciados para estos subgrupos de LA (AU)

The majority of childhood acute leukemias (AL) can be classified as lymphoblastic (mainly phenotype B or T) or myeloblastic, depending on the cell lineage of the blasts, requiring specific treatment according to this characterization. Immunotypification of AL is based on surface and/or intracytoplasmic antigen expression with lymhoid (B or T) or myeloide (My) blast differentiation, allowing definition of cell lineage and classification of the AL according to the grade of maturation. Nevertheless, there are rare cases of AL that are difficult to classify, denominated AL of ambiguous lineage (mixed/undifferentiated lineage) and acute dendritic cell leukemia. In AL of the mixed phenotype, the blasts express markers of more than one lineage and in undifferentiated AL, the blasts lack antigen expression of any specific lineage. Different conventions have tried to define and classify these unusual phenotypes, among which the most recent proposal of the World Health Organization (2008). According to the criteria of the latter, of 1301 cases of AL diagnosed between April 1994 and April 2009, 28 were re-classified as AL of ambiguous lineage, 3 as minimally differentiated acute myeloid leukemia, and 3 as acute dendritic cell leukemia. Characterization of these cases is important, as in the literature only sporadic reports of these rare phenotypes are found. Given the large number of patients with a long follow-up of the Garrahan Hospital, a review of these unusual cases allowed characterization from the point of view of the immunophenotype, morphology/cytochemistry, cytogenetics/molecular biology and to evaluate clinical presentation, evolution, response to treatment, and event-free survival to help define the prognosis and develop protocols for the treatment of these subgroups of AL (AU)

ABO genotyping in leukemia patients reveals new ABO variant alleles

The ABO blood group is the most important blood group system in transfusion medicine and organ transplantation. To date, more than 160 ABO alleles have been identified by molecular investigation. Almost all ABO genotyping studies have been performed in blood donors and families and for investigation of ABO subgroups detected serologically. The aim of the present study was to perform ABO genotyping in patients with leukemia. Blood samples were collected from 108 Brazilian patients with chronic myeloid leukemia (N = 69), chronic lymphoid leukemia (N = 13), acute myeloid leukemia (N = 15), and acute lymphoid leukemia (N = 11). ABO genotyping was carried out using allele specific primer polymerase chain reaction followed by DNA sequencing. ABO*O01 was the most common allele found, followed by ABO*O22 and by ABO*A103. We identified 22 new ABO* variants in the coding region of the ABO gene in 25 individuals with leukemia (23.2%). The majority of ABO variants was detected in O alleles (15/60.0%). In 5 of 51 samples typed as blood group O (9.8%), we found non-deletional ABO*O alleles. Elucidation of the diversity of this gene in leukemia and in other diseases is important for the determination of the effect of changes in an amino acid residue on the specificity and activity of ABO glycosyltransferases and their function. In conclusion, this is the first report of a large number of patients with leukemia genotyped for ABO. The findings of this study indicate that there is a high level of recombinant activity in the ABO gene in leukemia patients, revealing new ABO variants.

A importância da imunofenotipagem e da citogenética no diagnóstico das leucemias: uma revisão da literatura / The importance of immunophenotyping and cytogenetics in the diagnosis of leukemia: a literature review

As leucemias são grupos heterogêneos de neoplasias hematológicas, que resultam da transformação total ou parcial das células blásticas. Vários critérios, dentre eles a morfologia, a citoquímica, a imunofenotipagem e a detecção de alterações genéticasconstituem a base para classificação das neoplasias hematológicas. A imunofenotipagem, realizada com a técnica de citometria de fluxo (CMF), é útil tanto no diagnóstico, classificação, prognóstico, estadiamento, monitoramento, como na caracterização fenotípica das leucemias. Contudo, as análises citogenéticas e moleculares permitem uma definição mais precisa no diagnóstico das leucemias. Análisescitogenéticas e moleculares possibilitam a detecção de alterações cromossômicas e genéticas das células leucêmicas, correlacionando- as com o diagnóstico, a classificação, a caracterização de diferentes estágios, a avaliação da remissão e prognóstico destas enfermidades. As duas metodologias não se excluem mutuamente, mas, podem em conjunto beneficiar tanto o analista quanto o paciente, que certamente receberá um tratamento mais adequado e mais eficaz.

Leukemia is a heterogeneous group of hematological malignancies, resulting from the total or partial transformation of blastic cells. Several criteria, including cell morphology, cytochemistry, immunophenotyping, and the detection of genetic alterations are the basis for the classification of such hematological diseases. Immunophenotyping, performed with flow cytometry, is extremely useful for staging, diagnosis, classification, prognosis, and disease monitoring. However, cytogenetic and molecular analyses provide more precise diagnosis. Cytogenetics and molecular analyses describe the chromosomic changes in leukemic cells, and are useful for the correlation with diagnosis, classification, staging, prognostic and disease monitoring. The two methods do not exclude each other, but they can be used together in order to favor the clinical diagnosis as well as the patient that will surely receive a more suitable and efficient treatment.

Role of FAB classification of acute leukemias in era of immunophenotyping.

French-American-British classification for leukemias had been widely accepted due to its objectiveness and good reproducibility. WHO classification of leukemias was formulated in 1997 with a purpose of further enhancing the objectivity. However, the requirement of cytogenetics and immunophenotyping makes it difficult for many countries like India to put WHO classification in routine use. This study was carried to know the effectiveness of FAB classification in an era of technical advancement. A retrospective analysis of all acute leukemias over a period of 2 years was done. Out of total of 469 cases of acute leukemias, 193 were diagnosed as Acute Lymphoblastic Leukemia (ALL), 200 as Acute Myeloid Leukemia (AML), and 76 cases diagnosed as Acute Leukemia, cytochemically undifferentiated. Hence, only 16% of all leukemias remained unclassifiable. Subclassification of AML cases revealed a much higher percentage of AML-M3, as compared to western literature. In conclusion, FAB classification, based on morphology and simple cytochemical stains, remains effective enough, although cytogenetics and immunophenotyping can add to diagnostic accuracy in some cases.

Leucemias agudas / Acute leukemias

las leucemias agudas son un conjunto heterogéneo de neoplasia hematológica de origen multifactorial, causada por proliferaciones descontroladas de la célula hematopoyéticas inmaduras que lleva a una deficiente producción de células sanguíneas normales, con el progresivo deterioro del estado general de los pacientes, que si no son tratados a tiempo fallecen en pocas semanas o meses. El mecanismo molecular y genético que desencadena la transformación neoplásica de las células hematopoyéticas, se conoce en profundidad y han sido descritas diferentes variedades en base al origen celular de los blastos. Así mismo existen nuevas y mejores herramientas de diagnóstico, que permiten establecer con precisión el subtipo de leucemia aguda en cada caso, así como el pronóstico de la enfermedad. Estos avances han aumentado considerablemente la tasa de curaciones, especialmente en los niños. No obstante, aun queda mucho por hacer en el campo de la terapéutica. Las drogas actualmente disponibles para la quimioterapia, no consiguen erradicar completamente el clon leucémico y poseen muchísimos efectos colaterales. Hoy día, la leucemia aguda, continua siendo una enfermedad temible y potencialmente mortal. Un análisis profundo de las situaciones de los pacientes leucémicos en nuestro país, y los factores que impiden diagnosticar y tratar adecuadamente a estos pacientes, debería llevarnos a idear nuevas estrategias que nos permitan ofrecer a estos pacientes todas las alternativas diagnósticas y terapéuticas actualmente disponibles.

Leucemias agudas: primeiros sinais e sintomas em pacientes menores de 20 Anos no Hospital Universitário de Juiz de Fora / Universidade Federal de Juiz de Fora Medical research: how to improve students´ involvement

As leucemias agudas são as causas de câncer mais comuns na infância e seus sinais e sintomas, na maioria dos casos , são inespecíficos no inicío da doença; o que retarda o diagnóstico e consequentemente o tratamento. Este Trabalho visa analisar os prontuários de pacientes com diagnósticos e assim alertar os profissionais de saúde para que estes façam o diagnóstico mais alertar os profissionais da saúde para que estes façam o diagnóstico mais proprecocemente. Dentre os achados mais frequentes encontram-se: palidez (96,4%); febre (82,14%); hepatomegalia (75%); esplenomegalia (71,4%); linfadenomegalia (53,6%); anemia (92,9%); leucocitose (64,3); neutropenia (46,4%);trombocitopenia (88,5%) e blastos (71,43%).

Pax5 expression in Non-Hodgkin's Lymphomas and Acute Leukemias

The Pax5 gene encodes the B-cell-specific activator protein which is a key regulator in development and differentiation of B-cell. We studied the expression of Pax5 in hematologic malignancies to evaluate the diagnostic utility as a B cell marker. Materials included 70 B cell lymphomas, 26 T cell lymphomas, 53 acute leukemias, and 6 multiple myelomas (MMs). Representative areas from the paraffinembedded tissues were selected for tissue microarray, and the expressions of Pax5 was immunohistochemically evaluated. Pax5 was strongly expressed in most of the B cell lymphomas; 44 of 47 diffuse large B cell lymphomas (93.6%), 15 of 16 marginal zone B cell lymphomas (93.8%), all 3 mantle cell lymphomas, 2 follicular lymphomas, and 2 Burkitt's lymphomas (100%). However, Pax5 was expressed in only one of 26 T cell lymphomas. Among leukemias, it was expressed in 10 of the 14 B acute lymphocytic leukemias (ALLs) (72.4%), but also in 3 of the 6 T ALLs (50%), 13 of the 26 acute myelogenous leukemias (AMLs) (50%) and in all 3 ALL arising in chronic myelogenous leukemias and 4 mixed B ALL and AML. In MMs, Pax5 was negative in all cases. We concluded that Pax5 is very useful B cell marker in classification of lymphomas, but not of acute leukemias.

Flow cytometric analysis of childhood leukemias

OBJECTIVE: To collect demographic data for childhood [less than 15 years] leukemias in Karachi, describe the accuracy of the cell surface markers routinely used in the flow cytometric analysis of leukemic cells and arrive at an ideal panel of antibodies for analyzing leukemic samples. MATERIALS AND METHODS: Data from 62 consecutive cases of childhood leukemias referred to the Department of Pathology, Aga Khan University Hospital, [AKUH] between January 1995 and December 1998 was analyzed using Epi Info Version 6. Flow cytometry on all samples was performed using standard protocols. The mean age of patients was 8.2 years and 49 [79%] were males. Fifty [81%] had acute lymphoblastic leukemias of which 50% were CD10 positive and 24% CD10 negative Pre-B cell leukemias. Among all Pre B cell All 98% were positive for CD19, 96% for CD22, 89% for HLA-DR and 67% for CD10. Of the 10 AML cases, 100% were positive for CD33, 90% for CD13, 80% for CD19 and 70% for HLA-DR. The mean age in this study population was significantly higher and percentage of CD10 positive Pre-B All is lower than that in the West. Both these factors might be responsible for the poorer prognosis of these patients. It is not possible to specify a minimum or maximum panel of antibodies that should be used for phenotyping all cases of childhood leukemias. A certain degree or redundancy is essential in any panel of antibodies used for flow cytometry of leukemias

Clasificación de las leucemias agudas de acuerdo con el consenso de la primera conferencia latinoamericana en la tipificación inmunológica de las leucemias / Classification of acute leukemias according to the first Latinoamerican consensus conference for the immunophenotyping of leukemia

Objetivo. Evaluar las recomendaciones del consenso de la primera conferencia latinoamericana en la tipificación inmunológica de las leucemias agudas (LA) en pacientes con LA de novo, sin tratamiento previo y clasificados inmunológicamente empleando citometría de flujo y un panel extenso de anticuerpos monoclonales. Material y métodos. En la conferencia mencionada se decidió el empleo de los siguientes anticuerpos: CD79ac (c = citoplásmico) y CD19 para definir a la LA de linaje linfoide B (LAL-B); CD3c y CD7 para la LAL de estirpe T (LAL-T) y CD13, CD33 y mieloperoxidasa (MPOc) para la LA mieloide (LAM). Se analizó la expresión de estos antígenos celulares en 91 pacientes, no consecutivos, clasificados con el panel extenso como: LAL-B 28 casos; LAL-T 7; LAL-B-T 2; LAM 47 y LA de linaje mixto 7 casos. Resultados. Los 28 pacientes con LAL-B mostraron positividad con cada uno de los dos anticuerpos recomendados (CD79ac y CD19), mientras que, en 24 casos con LAM (en 23 casos no se estudió la expresión del CD79ac) y en 7 con LAL-T ambos antígenos estuvieron ausentes. Los antígenos CD3c y CD7 se identificaron en el 71 por ciento y 100 por ciento de los casos con LAL-T, respectivamente. El CD7 no se expresó en ninguno de los 28 casos de LAL-B pero si en 6 de los 47 casos de LAM, mientras que, el CD3c fue negativo en los 75 casos estudiados con LAL-B y LAM. El 49 por ciento de las LAM expresaron los tres marcadores recomendados (MPOc, CD13 y CD33), y el 51 por ciento de los casos resultaron positivos a uno o dos de estos tres anticuerpos. Seis de las 28 LAL-B tuvieron expresión aberrante de antígenos mieloides (3 casos del CD33 y 3 del CD13). Conclusiones. No hubo diferencia en la definición de linaje de las LA entre emplear el panel extenso de anticuerpos y el mínimo recomendado por el consenso latinoamericano.

Elderly acute leukemia: report of 40 cases

Between 1989 and 1996, 40 cases with acute leukemia [16 males and 24 females] were diagnosed in out institution. Median age was 65 years [range, 56- 88 years]. Leukocyte count was more than 30.109/1 in 42 percent of cases. According to the French-American-British [FAB] criteria, 11 cases were classified lymphoblastic and 29 myeloblastic. Sixteen patients have received palliative treatment because of there age and there bad performance status. Only 24 patients have received curative treatment. Complete remission was achieved in 12 cases [50 percent], 5 cases [20 percent] failed to respond and 7 [30 percent] died during induction. Relapse was observed in 8 cases. The 2-year survival rate was 10 percent confirming the worse prognosis of the acute leukemia in elderly