Trasplante alogénico en leucemia mieloide aguda y la importancia genética en desarrollo de nuevos tratamientos / Allological transplant in acute myeloid leukemia, the genetic importance for the development of new treatments

La Leucemia Mieloide Aguda es una enfermedad caracterizada por la alteración en la producción de células madre hematopoyéticas y la proliferación celular. Es más común en adultos; a pesar de ello solo se presenta en el 1 % en los Estados Unidos. Entre los 65-68 años se observa una mayor incidencia existiendo de 2-3 casos por cada año en 100.000 habitantes, siendo aproximadamente el 10 % de los cánceres de este tipo. Los diagnósticos más recomendados para esta enfermedad son los de carácter sanguíneo, la realización de citometrías de flujo en muestra de médula ósea. Según estudios, los análisis citogenéticos en un gran número de pacientes han demostrado translocaciones e inversiones en los cromosomas somáticos, mientras que solo una minoría tiene una organización de cromosomas somáticos balanceada. La terapia de consolidación se acompaña del trasplante de células madre hematopoyéticas, conocido como el trasplante alogénico, que puede ser potencialmente curativo en algunos pacientes.

The acute myeloid leukemia, is a disease which is a characterized by an irregular production of hematopoietic cells and cellular proliferation. It´s most common in adults, however only 1% of American adults will be diagnosed throughout their lives. Between the ages of 65-68 there is a high incidence with only 2-3 cases per 100.000 patients; making up only 10% of this type of cancer. It´s mainly diagnosed by using blood test, flow cytometry (on Bone Marrow samples). Some cytogenetic studies suggest that in a significant number of patients both somatic chromosomal inversion and translocation are present, while only a small percentage show no somatic chromosomal mutations. Consolidation therapy with a hematopoietic Stem Cells transplant, also known as a "allogenic transplant", can be potentially curative in some special cases.

Leucemia monoblastica aguda: complicaciones y respuesta a la quimioterapia de inducción. Reporte de cado / Acute monoblastic leukemia: complications and response to induction chemotherapy. Case report

La leucemia Monoblástica o Monocítica Aguda, es similar a otros subtipos de leucemias agudas, algunas peculiaridades que las diferencian son la hiperleucocitosis, infiltración extramedular y coagulación intravascular diseminada. El tratamiento de inducción se basa en drogas antracíclicas combinadas con citarabina; las complicaciones pueden ser fatales y la sobrevida a largo plazo se estima en 25% a 40%. Objetivo: documentar la r espuesta y complicaciones del tratamiento (quimioterapia) de inducción en la leucemia monoblástica aguda. Presentación de caso clínico: mujer de 34 años, acude con cuadr o inicial de congestión nasal bilateral y fiebre; examen físico normal, a excepción de equimosis en sitios de venopunción, el hemograma reveló anemia, leucocitosis y trombocitopenia. El frotis de sangre periférica, la biopsia y aspirado de médula ósea, fueron característicos de leucemia mieloide aguda tipo monocítica. Durante el tratamiento se administró dos ciclos de quimioterapia de inducción y coadyuvantes con base en hemoderivados, factor estimulante de colonias de granulocitos, antieméticos, antibióticos y antimicóticos. Complicaciones: se presentó toxicidad manifiesta por náuseas y vómitos grado II, mucositis, pérdida de peso y alopecia total, alteraciones hematológicas y complicaciones infecciosas grado IV. Se obtuvo remisión hematológica completa. Conclusión: es posible tr atar pacientes que sufr en leucemia monoblástica aguda tipo M5, en nuestro 1Universidad Nacional Autónoma de Honduras, Facultad de Ciencias Médicas, Tegucigalpa, Honduras. 2Laboratorios Molina, Tegucigalpa, Honduras. 3Investigador Independiente, Western International School, San Pedro Sula, Honduras. Autor de correspondencia: José Angel Sánchez N., jose.skiro@gmail.com Recibido: 03/12/2020 Aceptado: 15/05/2021 medio, con quimioterapia agresiva y obtener remisión hematológica completa. La identificación temprana de complicaciones y manejo oportuno es fundamental para evitar consecuencias fatales...(AU)

Inclusões semelhantes aos corpúsculos de Russell em blastos mieloides / Inclusions similar to Russell bodies in myeloblasts

Alterações nos mecanismos celulares resultam no aparecimento de corpúsculos de Russel, que são inclusões intracitoplasmáticas basofílicas. Estas inclusões ocorrem devido a uma indigestão celular de proteínas e podem ser observadas em diversas condições patológicas como leucemias, mieloma múltiplo, linfoma de Burkitt e gastrite com corpúsculos de Russell, sendo raramente observadas em leucemias mieloides agudas. O presente estudo relata a presença de inclusões semelhantes aos corpúsculos de Russell em blastos no sangue periférico de uma paciente de 51 anos com leucemia mieloide aguda.

Changes in cell mechanisms result in the appearance of Russel bodies, which are basophilic intracytoplasmic inclusions. These inclusions occur due to cellular indigestion of proteins, and can be observed in several pathological conditions such as leukemias, multiple myeloma, Burkitt's lymphoma, and gastritis with Russell bodies, but rarely observed in acute myeloid leukemias. The present study reports the presence of inclusions similar to Russell bodies in peripheral blood blasts in a 51-year-old female patient with acute myeloid leukemia.

Bradicardia inducida por quimioterapia en pacientes oncológicos / Chemotherapy-induced bradycardia in oncology patients

Resumen Introducción: cada día se reportan efectos tóxicos de la quimioterapia en el corazón, entre ellos las arritmias; sin embargo, las publicaciones sobre bradicardia ocasionada por antineoplásicos son escasas. Objetivo: describir y analizar la presencia de bradicardia posquimioterapia en el paciente oncológico. Materiales y métodos: estudio no experimental, descriptivo, retrospectivo, en el que se incluyeron pacientes atendidos durante el año 2017 en un Servicio de Cardiología, a causa de bradicardia posquimioterapia. Resultados: se evaluaron 59 pacientes, 31 varones (52,5%) y 28 mujeres (47,5%), con una mediana de edad de 42 años. La mediana de la frecuencia cardiaca fue 46 latidos por minuto. La bradicardia fue más frecuente en leucemia mielocítica aguda (25,42%), seguida por leucemia linfoblástica aguda (20,34%). Fue asintomática en el 88,13% de los casos. Los fármacos quimioterápicos relacionados con bradicardia en leucemia mielocítica aguda fueron la citarabina en combinación con la daunorubicina, mientras que en leucemia linfoblástica aguda fueron la vincristina en combinación con la daunorubicina. Se presentó intervalo QTc largo en 12 casos (20,34%). El tiempo entre quimioterapia y el inicio de la bradicardia fue 24 a 48 horas en 35,6% y la recuperación de la frecuencia cardiaca fue entre 24 a 48 horas en el 61,02%. Conclusiones: la bradicardia sinusal como efecto adverso de la quimioterapia, es más frecuente en la leucemia mielocítica aguda, mientras que los medicamentos antineoplásicos relacionados con la bradicardia más comunes fueron la citarabina y la daunorubicina.

Abstract Introduction: There are daily reports of the toxic effects of chemotherapy on the heart, among them are the arrhythmias. However, there are very few publications on bradycardia caused by anti-neoplastic treatment. Objective: To describe and analyse the presence of post-chemotherapy bradycardia in the oncology patient. Materials and methods: A non-experimental, descriptive and retrospective study was conducted on patients seen during the year 2017 in a Cardiology Department due to post-chemotherapy bradycardia. Results: A total of 59 patients were evaluated, of whom 31 (52.5%) were males and 28 (47.5%) women, and with a median age of 42 years. The median heart rate was 46 beats per minute. The bradycardia was more common in acute myelocytic leukaemia (25.42%), followed by acute lymphoblastic leukaemia (20.34%). It was asymptomatic in 88.31% of cases. The chemotherapy drugs associated with bradycardia in acute myelocytic leukaemia were cytarabine in combination with daunorubicin, whilst in acute lymphoblastic leukaemia they were vincristine in combination with daunorubicin. A prolonged QTc interval was present in 12 (20.34%) of cases. The time between the chemotherapy and the onset of bradycardia was 24 to 48 hours in 35.6%, and the recovery of the heart rate was between 24 and 48 hours in 61.02%. Conclusions: Sinus bradycardia as an adverse effect of chemotherapy is more frequent in acute myelocytic leukaemia, whilst the most common anti-neoplastic drugs associated with bradycardia were cytarabine and daunorubicin.

Proteinosis alveolar secundaria: reporte de un caso / Proteinosis alveolar secundaria: case report

La proteinosis alveolar es un enfermedad caracterizada por el acúmulo anormal de surfactante en el espacio alveolar lo que conlleva a disrupción en el intercambio gaseoso. Su fisiopatogenia es variada y en los adultos la forma secundaria es la más frecuente. Presentamos el caso de una paciente con leucemia mieloide aguda en tratamiento compasivo con gemtuzumab ozogamicina, e infecciones respiratorias a repetición que se presenta con disnea progresiva y tos seca. Luego de descartar causa embólica y cardíaca, se realiza tomografía que evidencia opacidades en vidrio esmerilado de distribución difusa y engrosamiento de septos, por lo que ante la sospecha de infección se realiza lavado broncoalveolar que revela líquido blanquecino evidenciando en la citología inclusiones en macrógrafos PAS positivo. Con el diagnóstico de proteinosis alveolar secundaria a enfermedad de base, se reinició tratamiento quimioterápico. Presentó progresión de infiltrados y mayor requerimiento de oxígeno falleciendo pocos días después. (AU)

Pre-analytical parameters associated with unsuccessful karyotyping in myeloid neoplasm: a study of 421 samples

Cytogenetics is essential in myeloid neoplasms (MN) and pre-analytical variables are important for karyotyping. We assessed the relationship between pre-analytical variables (time from collection to sample processing, material type, sample cellularity, and diagnosis) and failures of karyotyping. Bone marrow (BM, n=352) and peripheral blood (PB, n=69) samples were analyzed from acute myeloid leukemia (n=113), myelodysplastic syndromes (n=73), myelodysplastic syndromes/myeloproliferative neoplasms (n=17), myeloproliferative neoplasms (n=137), and other with conclusive diagnosis (n=6), and reactive disorders/no conclusive diagnosis (n=75). The rate of unsuccessful karyotyping was 18.5% and was associated with the use of PB and a low number of nucleated cells (≤7×103/µL) in the sample. High and low cellularity in BM and high and low cellularity in PB samples showed no metaphases in 3.9, 39.7, 41.9, and 84.6% of cases, respectively. Collecting a good BM sample is the key for the success of karyotyping in MN and avoids the use of expensive molecular techniques.

Characterization and Cytotoxic Evaluation of Silver and Gold Nanoparticles Produced with Aqueous Extract of Lavandula dentata L. in Relation to K-562 Cell Line

Abstract Metallic nanoparticles have great potential as a chemotherapeutic agent. The aim of this study was to develop and characterize silver and gold nanoparticles using a simple method, as well as evaluating the potential cytotoxic activity in relation to the K-562 cell line. For the synthesis, a solution containing the metallic ions was subjected to magnetic stirring with the aqueous extract of Lavandula dentata L. and a change of colour was observed. With the data obtained from the analyses we concluded that the nanoparticles were successfully obtained by a simple and green method using the aqueous extract of L. dentata. The obtained nanoparticles presented a reduced size, a low level of polydispersion, and a homogenous spherical shape. The nanoparticles presented intense and characteristic diffraction peaks, which could be correlated to the planes of the centred cubic structure of the silver and gold. The two formulations presented predominantly crystalline characteristics. The infrared analysis suggested that the amides and alcohols present in the samples may have been responsible for the reduction and limitation of the size and dispersion of the silver and gold nanoparticles. The cytotoxic assay showed that the nanoparticles demonstrated great potential to reduce the cell viability of the K-562 cell line, especially the gold nanoparticles.

Situación actual de la leucemia mieloide crónica en Costa Rica / (Current situation of chronic myeloid leukemia in Costa Rica)

Resumen Justificación y objetivo: la leucemia mieloide crónica constituye un paradigma de reversión de neoplasia con un tratamiento específico basado en los inhibidores de tirosina quinasa. Aunque la situación epidemiológica ha sido estudiada en países primermundistas, los estudios en Latinoamérica son escasos. Con el fin de actualizar la situación real de la LMC en la región centroamericana, el estudio pretende describir la epidemiología de la leucemia mieloide crónica en Costa Rica. Métodos: se evaluaron 133 pacientes con la enfermedad, mediante monitoreo hematológico y molecular. Se analizó la respuesta de estos casos a tratamiento conforme a las siguientes variables: respuesta hematológica, respuesta molecular y supervivencia global, libre de evento, progresión, así como la prevalencia de mutaciones que confieren resistencia al tratamiento. Resultados: la respuesta hematológica completa fue del 97,7%, y la molecular mayor, a los 12 meses, fue del 43,4%. El seguimiento recomendado por la guía European LeukemiaNet se alcanzó solo en un 68,4% de los pacientes en el primer año, bajando al 57,7%, posteriormente. Un total de 92 pacientes alcanzó respuesta molecular mayor en algún momento; de ellos, el 87,0% conservó respuesta. La supervivencia libre de evento a 3 años fue del 65,7%, libre de progresión del 92,2% y global del 89,2%. La mutación más frecuente encontrada en el gen ABL fue la T315I. Conclusión: el tratamiento de la leucemia mieloide crónica en Costa Rica presenta una eficacia comparable a lo reportado en otros países, con una respuesta molecular mayor inferior a lo esperado, debido a dificultades de acceso al medicamento y monitoreo de la enfermedad.

Abstract Background and aim: Chronic myeloid leukemia is a paradigm of reversion of neoplasia with a specific treatment based on tyrosine kinase inhibitors. Although the epidemiological situation has been studied in first world countries, studies in Latin American countries are scarce. In order to update the real situation of the chronic myeloid leukemia in our Central American region, this study aims to describe the epidemiology of chronic myeloid leukemia in Costa Rica. Methods: 133 patients with the disease were evaluated through hematological and molecular monitoring. The response of these cases to treatment was analyzed by the following variables: haematological response, molecular response and overall survival, event-free, progression, as well as the prevalence of mutations that confer resistance to treatment. Results: The complete haematological response was 97.7% and the molecular response greater than 12 months was 43.4%. The follow-up recommended by the European LeukemiaNet guideline was reached in only 68.4% of the patients in the first year, decreasing to 57.7% later on. A total of 92 patients achieved a higher molecular response at some point, of which 87.0% retained a response. The 3-year event-free survival was 65.7%, progression free of 92.2% and overall of 89.2%. The most frequent mutation found in the ABL gene was T315I. Conclusion: The treatment of chronic myeloid leukemia in Costa Rica presents an efficacy comparable to that reported in other countries, with a lower molecular response than expected due to difficulties in accessing medication and monitoring the disease.

Clinical and pathological features of myeloid leukemia cutis

Abstract: Background: Myeloid leukemia cutis is the terminology used for cutaneous manifestations of myeloid leukemia. Objective: The purpose of this study was to study the clinical, histopathological and immunohistochemical features of myeloid leukemia cutis. Methods: This was a retrospective study of clinical and pathological features of 10 patients with myeloid leukemia cutis. Results: One patient developed skin lesions before the onset of leukemia, seven patients developed skin infiltration within 4-72 months after the onset of leukemia, and two patients developed skin lesions and systemic leukemia simultaneously. Of these patients, five presented with generalized papules or nodules, and five with localized masses. The biopsy of skin lesions showed a large number of tumor cells within the dermis and subcutaneous fat layer. Immunohistochemical analysis showed strong reactivity to myeloperoxidase (MPO), CD15, CD43 and CD45 (LCA) in most cases. NPM1 (nucleophosmin I) and FLT3-ITD (Fms-like tyrosine kinase 3-internal tandem duplication) mutations were identified in one case. Five patients with acute myelogenous leukemia and one patient with chronic myelomonocytic leukemia died within two months to one year after the onset of skin lesions. Study limitations: This was a retrospective and small sample study. Conclusions: In patients with myelogenous leukemia, skin infiltration usually occurs after, but occasionally before, the appearance of hemogram and myelogram abnormalities, and the presence of skin infiltration is often associated with a poor prognosis and short survival time. myeloid leukemia cutis often presents as generalized or localized nodules or masses with characteristic pathological and histochemical findings.

Bullous pyoderma gangrenosum as a predictor of hematological malignancies

Abstract: Pyoderma gangrenosum may precede, coexist or follow diverse systemic diseases. The bullous variety is usually associated with hematologic disorders. From 31 patients with pyoderma gangrenosum diagnosed in our hospital during 10 years, only 2 presented with the bullous type. One patient had previous diagnosis of chronic myeloid leukemia. Both had fast-progressive, painful lesions, and both showed an excellent response to systemic corticosteroids. In less than 3 months the lesions recurred simultaneously with the progression of chronic myeloid leukemia in one patient and with the initial diagnosis of acute myeloid leukemia in the other one. They died in less than four weeks. These findings emphasize the importance of its timely diagnosis. Cutaneous lesions could be the first predictor of an underlying disease.

Cytotoxic and pro-apoptotic action of MjTX-I, a phospholipase A2 isolated from Bothrops moojeni snake venom, towards leukemic cells

A leucemia mieloide crônica (LMC) é uma neoplasia mieloproliferativa BCR-ABL1 + marcada por aumento da mieloproliferação e presença de células leucêmicas resistentes à apoptose. A terapia de primeira linha atual para a LMC é a administração de inibidores da tirosina quinase, mesilato de imatinibe, dasatinibe ou nilotinibe. Embora eficaz no tratamento da LMC, alguns pacientes se tornaram resistentes a essa terapia, levando à progressão da doença e à morte. Assim, a descoberta de novos compostos para melhorar a terapia da LMC ainda é um desafio. Aqui, os destinatários se MjTX-I, uma fosfolipase A 2 isolado a partir de Bothrops moojeni de veneno de cobra, afecta a viabilidade de Bcr-Abl de mesilato de imatinib-resistente + linhas celulares. Métodos: Examinamos o efeito citotóxico e pró-apoptótico de MjTX-I em células K562-S e K562-R Bcr-Abl + e na linha de células HEK-293 não tumorais e células mononucleares de sangue periférico, usando o 3- (4, Brometo de 5-dimetiltiazol-2-il) -2,5-difeniltetrazólio e os métodos de solução fluorescente hipotônica, associados à detecção de ativação de caspases 3, 8 e 9 e clivagem de poli (ADP-ribose) polimerase (PARP). Também analisamos o potencial MjTX-I para modular a expressão de genes relacionados à apoptose em células K562-S e K562-R. Resultados: O MjTX-I diminuiu a viabilidade das células K562-S e K562-R em 60 a 65%, sem afetar a viabilidade das células não tumorais, ou seja, exerceu citotoxicidade seletiva para as linhagens celulares Bcr-Abl + . Em linhas de células leucêmicas, a toxina induziu apoptose, caspases 3, 8 e 9 ativadas, PARP clivada, expressão negativa do gene anti-apoptótico BCL-2 e expressão aumentada do gene pró-apoptótico BAD. Conclusão: O efeito antitumoral de MjTX-I está associado ao seu potencial para induzir apoptose e citotoxicidade em linhagens celulares positivas para Bcr-Abl sensíveis e resistentes ao mesilato de imatinibe, indicando que MjTX-I é um candidato promissor a fármaco para atualizar a terapia de LMC.(AU)

Insulin Substrate Receptor (IRS) proteins in normal and malignant hematopoiesis

The insulin receptor substrate (IRS) proteins are a family of cytoplasmic proteins that integrate and coordinate the transmission of signals from the extracellular to the intracellular environment via transmembrane receptors, thus regulating cell growth, metabolism, survival and proliferation. The PI3K/AKT/mTOR and MAPK signaling pathways are the best-characterized downstream signaling pathways activated by IRS signaling (canonical pathways). However, novel signaling axes involving IRS proteins (noncanonical pathways) have recently been identified in solid tumor and hematologic neoplasm models. Insulin receptor substrate-1 (IRS1) and insulin receptor substrate-2 (IRS2) are the best-characterized IRS proteins in hematologic-related processes. IRS2 binds to important cellular receptors involved in normal hematopoiesis (EPOR, MPL and IGF1R). Moreover, the identification of IRS1/ABL1 and IRS2/JAK2V617F interactions and their functional consequences has opened a new frontier for investigating the roles of the IRS protein family in malignant hematopoiesis. Insulin receptor substrate-4 (IRS4) is absent in normal hematopoietic tissues but may be expressed under abnormal conditions. Moreover, insulin receptor substrate-5 (DOK4) and insulin receptor substrate-6 (DOK5) are linked to lymphocyte regulation. An improved understanding of the signaling pathways mediated by IRS proteins in hematopoiesis-related processes, along with the increased development of agonists and antagonists of these signaling axes, may generate new therapeutic approaches for hematological diseases. The scope of this review is to recapitulate and review the evidence for the functions of IRS proteins in normal and malignant hematopoiesis.

La exposición ocupacional al formol y la nueva tabla de enfermedades laborales / Occupational exposure to formaldehyde and new table of occupational diseases

RESUMEN En este documento se presenta una actualización referente al efecto carcinógeno del formol; inicialmente se consideran generalidades de su composición química, luego se evidencian algunos de sus usos, tanto en la industria como en las instituciones de salud, y posteriormente se muestra el riesgo al que está expuesta la población general y en particular el personal del área de la salud, como consecuencia de una exposición prolongada ante este componente químico. Se hace hincapié en la concentración del formaldehido tanto en la vida cotidiana como en el ámbito laboral y se consideran los lineamientos del decreto 1477 del 5 de agosto de 2014, emanado por el Ministerio del Trabajo de la República de Colombia, sobre la exposición ocupacional a esta sustancia química resaltando que este decreto no hace mención a los ya conocidos efectos car-cinogénicos del formol, ampliamente soportados por la evidencia científica, dejando un vacío tanto para la prevención ocupacional como para la legislación laboral.(AU)

ABSTRACT This paper presents an update on the carcinogenic effect of formaldehyde. First, generalities of its chemical composition are considered, followed by the description of some of its uses, both in the industry and in health institutions, as well as an account of the risk to which the general population is exposed, in particular health personnel, as a result of prolonged exposure to this chemical component. Emphasis is placed on the concentration of formaldehyde in everyday life and in the workplace, while the guidelines of decree 1477 of August 5, 2014, issued by the Ministry of Labor of Colombia, on occupational exposure to this chemical are analyzed to demonstrate that this decree does not consider the already known carcinogenic effects of formaldehyde, widely supported by scientific evidence, thus leaving a void for both occupational prevention and labor legislation.(AU)

El priapismo en la Leucemia Mieloide Crónica Hallazgos radiológicos en casos de Leucemia Mieloide Crónica que se presentaron con priapismo / 7 PRIAPISM IN CHRONIC MYELOID LEUKEMIA : IMAGING FINDINGS IN CASES OF CHRONIC MYELOID LEUKEMIA WHO PRESENTED WITH PRIAPISM

El priapismo es una emergencia urológica que debe ser diagnosticada y tratada apropiadamente. Específicamente en casos conocidos de leucemia el pene turgente doloroso debe hacer surgir la sospecha de priapismo de primera movida y el Doppler peneano debe ser la mera línea de modalidad de imágenes. Esta información debe ser transmitida al paciente y al departamento clínico emergentológico

Priapism is an urological emergency and must be diagnosed and treated appropriately. Specifically in known cases of leukemia painful turgid penis should raise suspicion of priapism in first hand and penile Doppler should be the first line of imaging modality. This information should be forwarded to patient and emergency department clinician

Leucemia mieloide crónica en niño de 2 años. Reporte de caso / Chronic myelogenous leukemia in a 2 year-old boy. Case report

La leucemia mieloide crónica (LMC) representa el 3% de las leucemias pediátricas diagnosticadas y su incidencia es de 0,7 millones por año, extremadamente rara entre las edades de 1 a 14 años y debido a esta inusual presentación existen pocos casos descritos. La patogénesis molecular de la LMC implica la fusión quimérica de la proteína BCR-ABL, cuyo aumento constitutivo de la actividad tirosina quinasa, contribuido por el componente ABL, parece ser el causante de la alteración molecular en la LMC. La identificación de esta proteína quimérica resultó en el desarrollo exitoso del mesilato de imatinib, fármaco que ha revolucionado el tratamiento de esta enfermedad. El tratamiento con imatinib en niños ha logrado alcanzar un 90% de remisión completa a los 5 años, sustituyendo de esta manera al trasplante alogénico como primera línea de terapia. A continuación reportamos el caso de un niño de 2 años cuyo hemograma reportó: anemia microcítica moderada (hemoglobina de 11,7 g%), hiperleucocitosis (leucocitos 80,8 x10(9)/L), y trombocitosis (721x10(9)/L). Los estudios de citogenética, FISH y RT-PCR para BCR-ABL1 dieron positivos, confirmando el diagnóstico de LMC en fase crónica. Se inició inmediatamente el tratamiento con imatinib y a 3 años del diagnóstico el paciente se encuentra en remisión completa a nivel molecular, con ausencia del clon neoplásico y sin haber presentado efectos colaterales adversos de importancia.

Chronic myeloid leukemia (CML) accounts for 3% of all diagnosed pediatric leukemias. It has an incidence of 0.7 million per year, rarely diagnosed between the ages of 1 to 14 years, so few cases have been reported. The CML molecular pathogenesis involves a chimeric fusion of the BCR-ABL protein which increased constitutive tyrosine kinase activity contributed by ABL component seems to be the cause of the molecular alteration in CML. The identification of this chimeric protein resulted in the successful development of imatinib mesylate, a drug that has revolutionized the treatment of this disease. The use of imatinib in children has reached 90% of complete remission at 5 years, replacing in this way the allogeneic transplant as first-line therapy. This report presents the case of a 2 year old child whose CBC reported: moderate microcytic anemia (hemoglobin 11.7 g%), hyperleukocytosis (leukocytes 80.8 x10(9)/L) and thrombocytosis (721x10(9)/ L). Cytogenetic, FISH and RT-PCR Studies for BCR-ABL1 were positive, confirming the diagnosis of CML in chronic phase. Treatment with imatinib was initiated immediately and 3 years after diagnosis the patient is in complete molecular remission with the absence of neoplastic clone and without having presented significant side effects.