Validation of Endogenous Control Genes by Real-Time Quantitative Reverse Transcriptase Polymerase Chain Reaction for Acute Leukemia Gene Expression Studies.

Reference genes are used as internal reaction controls for gene expression analysis, and for this reason, they are considered reliable and must meet several important criteria. In view of the absence of studies regarding the best reference gene for the analysis of acute leukemia patients, a panel of genes commonly used as endogenous controls was selected from the literature for stability analysis: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Abelson murine leukemia viral oncogene human homolog 1 (ABL), Hypoxanthine phosphoribosyl-transferase 1 (HPRT1), Ribosomal protein lateral stalk subunit P0 (RPLP0), ß-actin (ACTB) and TATA box binding protein (TBP). The stability of candidate reference genes was analyzed according to three statistical methods of assessment, namely, NormFinder, GeNorm and R software (version 4.0.3). From this study's analysis, it was possible to identify that the endogenous set composed of ACTB, ABL, TBP and RPLP0 demonstrated good performances and stable expressions between the analyzed groups. In addition to that, the GAPDH and HPRT genes could not be classified as good reference genes, considering that they presented a high standard deviation and great variability between groups, indicating low stability. Given these findings, this study suggests the main endogenous gene set for use as a control/reference for the gene expression in peripheral blood and bone marrow samples from patients with acute leukemias is composed of the ACTB, ABL, TBP and RPLP0 genes. Researchers may choose two to three of these housekeeping genes to perform data normalization.

Development and Clinical Applications of PI3K/AKT/mTOR Pathway Inhibitors as a Therapeutic Option for Leukemias.

Leukemias are hematological neoplasms characterized by dysregulations in several cellular signaling pathways, prominently including the PI3K/AKT/mTOR pathway. Since this pathway is associated with several important cellular mechanisms, such as proliferation, metabolism, survival, and cell death, its hyperactivation significantly contributes to the development of leukemias. In addition, it is a crucial prognostic factor, often correlated with therapeutic resistance. Changes in the PI3K/AKT/mTOR pathway are identified in more than 50% of cases of acute leukemia, especially in myeloid lineages. Furthermore, these changes are highly frequent in cases of chronic lymphocytic leukemia, especially those with a B cell phenotype, due to the correlation between the hyperactivation of B cell receptors and the abnormal activation of PI3Kδ. Thus, the search for new therapies that inhibit the activity of the PI3K/AKT/mTOR pathway has become the objective of several clinical studies that aim to replace conventional oncological treatments that have high rates of toxicities and low specificity with target-specific therapies offering improved patient quality of life. In this review we describe the PI3K/AKT/mTOR signal transduction pathway and its implications in leukemogenesis. Furthermore, we provide an overview of clinical trials that employed PI3K/AKT/mTOR inhibitors either as monotherapy or in combination with other cytotoxic agents for treating patients with various types of leukemias. The varying degrees of treatment efficacy are also reported.

Association between Immunophenotypic Parameters and Molecular Alterations in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a hematologic malignancy that occurs due to alterations such as genetic mutations, chromosomal translocations, or changes in molecular levels. These alterations can accumulate in stem cells and hematopoietic progenitors, leading to the development of AML, which has a prevalence of 80% of acute leukemias in the adult population. Recurrent cytogenetic abnormalities, in addition to mediating leukemogenesis onset, participate in its evolution and can be used as established diagnostic and prognostic markers. Most of these mutations confer resistance to the traditionally used treatments and, therefore, the aberrant protein products are also considered therapeutic targets. The surface antigens of a cell are characterized through immunophenotyping, which has the ability to identify and differentiate the degrees of maturation and the lineage of the target cell, whether benign or malignant. With this, we seek to establish a relationship according to the molecular aberrations and immunophenotypic alterations that cells with AML present.

Lower access to risk stratification tests and drugs, and worse survival of chronic lymphocytic leukaemia patients treated in public as compared to private hospitals in Brazil: A retrospective analysis of the Brazilian registry of chronic lymphocytic leukaemia.

Chronic lymphocytic leukaemia (CLL) has a highly variable clinical course. In addition to biological factors, socioeconomic factors and health system characteristics may influence CLL outcome. Data from the Brazilian Registry of CLL were analyzed to compare clinical and treatment-related characteristics in patients with CLL, from public or private institutions. A total of 3326 patients from 43 centres met the eligibility criteria, of whom 81% were followed up at public hospitals and 19% at private hospitals. The majority were male (57%), with a median age of 65 years. Comparing public and private hospitals, patients in public hospitals were older, had more advanced disease at diagnosis, and more frequently had elevated creatinine levels. All investigated prognostic markers were evaluated more often in private hospitals. First-line treatment was predominantly based on chlorambucil in 41% of the cases and fludarabine in 38%. Anti-CD20 monoclonal antibody was used in only 36% of cases. In public hospitals, significantly fewer patients received fludarabine-based regimens and anti-CD20 monoclonal antibodies. Patients from public hospitals had significantly worse overall survival (71% vs. 90% for private hospitals, p < 0.0001) and treatment-free survival (32% vs. 40%, for private hospitals, p < 0.0001) at seven years. Our data indicate striking differences between patients followed in public and private hospitals in Brazil. A worse clinical condition and lack of accessibility to basic laboratory tests and adequate therapies may explain the worse outcomes of patients treated in public institutions.

Kinase Inhibition in Multiple Myeloma: Current Scenario and Clinical Perspectives.

Multiple myeloma (MM) is a blood cell neoplasm characterized by excessive production of malignant monoclonal plasma cells (activated B lymphocytes) by the bone marrow, which end up synthesizing antibodies or antibody fragments, called M proteins, in excess. The accumulation of this production, both cells themselves and of the immunoglobulins, causes a series of problems for the patient, of a systemic and local nature, such as blood hyperviscosity, renal failure, anemia, bone lesions, and infections due to compromised immunity. MM is the third most common hematological neoplasm, constituting 1% of all cancer cases, and is a disease that is difficult to treat, still being considered an incurable disease. The treatments currently available cannot cure the patient, but only extend their lifespan, and the main and most effective alternative is autologous hematopoietic stem cell transplantation, but not every patient is eligible, often due to age and pre-existing comorbidities. In this context, the search for new therapies that can bring better results to patients is of utmost importance. Protein tyrosine kinases (PTKs) are involved in several biological processes, such as cell growth regulation and proliferation, thus, mutations that affect their functionality can have a great impact on crucial molecular pathways in the cells, leading to tumorigenesis. In the past couple of decades, the use of small-molecule inhibitors, which include tyrosine kinase inhibitors (TKIs), has been a hallmark in the treatment of hematological malignancies, and MM patients may also benefit from TKI-based treatment strategies. In this review, we seek to understand the applicability of TKIs used in MM clinical trials in the last 10 years.

Leukemic Stem Cell: A Mini-Review on Clinical Perspectives.

Hematopoietic stem cells (HSCs) are known for their ability to proliferate and self-renew, thus being responsible for sustaining the hematopoietic system and residing in the bone marrow (BM). Leukemic stem cells (LSCs) are recognized by their stemness features such as drug resistance, self-renewal, and undifferentiated state. LSCs are also present in BM, being found in only 0.1%, approximately. This makes their identification and even their differentiation difficult since, despite the mutations, they are cells that still have many similarities with HSCs. Although the common characteristics, LSCs are heterogeneous cells and have different phenotypic characteristics, genetic mutations, and metabolic alterations. This whole set of alterations enables the cell to initiate the process of carcinogenesis, in addition to conferring drug resistance and providing relapses. The study of LSCs has been evolving and its application can help patients, where through its count as a biomarker, it can indicate a prognostic factor and reveal treatment results. The selection of a target to LSC therapy is fundamental. Ideally, the target chosen should be highly expressed by LSCs, highly selective, absence of expression on other cells, in particular HSC, and preferentially expressed by high numbers of patients. In view of the large number of similarities between LSCs and HSCs, it is not surprising that current treatment approaches are limited. In this mini review we seek to describe the immunophenotypic characteristics and mechanisms of resistance presented by LSCs, also approaching possible alternatives for the treatment of patients.

Role of miRNAs in Human T Cell Leukemia Virus Type 1 Induced T Cell Leukemia: A Literature Review and Bioinformatics Approach.

Human T cell leukemia virus type 1 (HTLV-1) was identified as the first pathogenic human retrovirus and is estimated to infect 5 to 10 million individuals worldwide. Unlike other retroviruses, there is no effective therapy to prevent the onset of the most alarming diseases caused by HTLV-1, and the more severe cases manifest as the malignant phenotype of adult T cell leukemia (ATL). MicroRNA (miRNA) dysfunction is a common feature of leukemogenesis, and it is no different in ATL cases. Therefore, we sought to analyze studies that reported deregulated miRNA expression in HTLV-1 infected cells and patients' samples to understand how this deregulation could induce malignancy. Through in silico analysis, we identified 12 miRNAs that stood out in the prediction of targets, and we performed functional annotation of the genes linked to these 12 miRNAs that appeared to have a major biological interaction. A total of 90 genes were enriched in 14 KEGG pathways with significant values, including TP53, WNT, MAPK, TGF-ß, and Ras signaling pathways. These miRNAs and gene interactions are discussed in further detail for elucidation of how they may act as probable drivers for ATL onset, and while our data provide solid starting points for comprehension of miRNAs' roles in HTLV-1 infection, continuous effort in oncologic research is still needed to improve our understanding of HTLV-1 induced leukemia.

Can SARS-CoV-2 induce hematologic malignancies in predisposed individuals? A case series and review of the literature.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) may present with extrapulmonary manifestations, including hematologic changes. Previous studies suggest that severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) can interact with the renin-angiotensin system, ultimately causing increased production of angiotensin II. By reporting the cases of previously healthy young adults diagnosed with a hematologic malignancy after experiencing COVID-19, we raise the hypothesis that the SARS-Cov-2 infection could act as a trigger for leukemogenesis in predisposed individuals. METHODS: This was a case series performed through extraction of relevant clinical information from the medical records of three patients admitted to our Hematology unit between August 2020 and September 2020. MAIN RESULTS: Considering the relatively rapid development of cytopenias following recovery from COVID-19, it cannot be ruled out that SARS-Cov-2 played a role in leukemogenesis in those patients. Based on previous in vitro studies, the renin-angiotensin system imbalance induced by SARS-CoV-2 could potentially promote in vivo leukemogenesis through several mechanisms. CONCLUSION: Despite the advances in pathophysiological and clinical characterization of COVID-19, the consequences of the pandemic to the incidence of hematologic diseases are still to be elucidated. In this context, future dissection of the status of the local bone marrow renin-angiotensin system in leukemogenesis is a clinically relevant basic research area.

Can SARS-CoV-2 induce hematologic malignancies in predisposed individuals? A case series and review of the literature

Abstract Introduction Coronavirus disease 2019 (COVID-19) may present with extrapulmonary manifestations, including hematologic changes. Previous studies suggest that severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) can interact with the renin-angiotensin system, ultimately causing increased production of angiotensin II. By reporting the cases of previously healthy young adults diagnosed with a hematologic malignancy after experiencing COVID-19, we raise the hypothesis that the SARS-Cov-2 infection could act as a trigger for leukemogenesis in predisposed individuals. Methods This was a case series performed through extraction of relevant clinical information from the medical records of three patients admitted to our Hematology unit between August 2020 and September 2020. Main Results Considering the relatively rapid development of cytopenias following recovery from COVID-19, it cannot be ruled out that SARS-Cov-2 played a role in leukemogenesis in those patients. Based on previous in vitro studies, the renin-angiotensin system imbalance induced by SARS-CoV-2 could potentially promote in vivo leukemogenesis through several mechanisms. Conclusion Despite the advances in pathophysiological and clinical characterization of COVID-19, the consequences of the pandemic to the incidence of hematologic diseases are still to be elucidated. In this context, future dissection of the status of the local bone marrow renin-angiotensin system in leukemogenesis is a clinically relevant basic research area.

Sarcoma Granulocítico Cutâneo de Apresentação Concomitante ao Diagnóstico de Leucemia Promielocítica Aguda / Cutaneous Granulocytic Sarcoma Concomitant to the Diagnosis of Acute Promyelocytic Leukemia / Sarcoma Granulocitico Cutaneo de Presentacion Concomitente al Diagnostico de Leucemia Promielocitica Aguda

Introdução: O sarcoma granulocítico (SG) é um tumor extramedular raro, composto por células mieloides imaturas. Ocorre em 2% a 14% dos pacientes com leucemia mieloide aguda (LMA). A associação com leucemia promielocítica (LPA) é ainda mais rara, especialmente como manifestação no momento do diagnóstico. O presente estudo expõe o caso de um paciente com SG cutâneo de apresentação concomitante ao diagnóstico de LPA. Relato do caso: Paciente do sexo masculino, 30 anos, encaminhado ao Departamento de Hematologia por febre, odinofagia, intensa adinamia, hiporexia, perda de 5 kg, sudorese noturna, além de dispneia progressiva ao longo de um mês. Realizou exames laboratoriais com evidência de anemia grave, prosseguindo investigação etiológica com mielograma, que evidenciou 84% de blastos, e imunofenotipagem compatível com LPA, PML-RARA positivo (90%). Apresentava ainda lesões ulceradas em região genital e coxa direita, cuja biópsia evidenciou proliferação de células redondas suspeita para infiltração por LMA/SG. A imuno-histoquímica confirmou SG. O paciente foi submetido à quimioterapia, com boa resposta ao tratamento e melhora das contagens sanguíneas. As lesões cutâneas evoluíram com cicatrização. Após terceira consolidação, o PML-RARA negativou. Conclusão: Este relato de caso descreve uma apresentação rara de uma doença hematológica maligna, o SG, também conhecido como cloroma, na pele. Uma estratégia de diagnóstico incluindo imagens, histopatologia, imuno-histoquímica e exames laboratoriais foi necessária para confirmá-lo. O diagnóstico oportuno é essencial para que o tratamento adequado seja instituído logo, beneficiando o paciente em sobrevida e qualidade de vida

Introduction: Granulocytic sarcoma (GS) is a rare extramedullary tumor, made up by immature myeloid cells. It occurs in 2% to 14% of patients with acute myeloid leukemia (AML). The association with promyelocytic leukemia (APL) is even more rare, especially as manifestation at the time of diagnosis. The present study exposes the case of a patient with cutaneous GS concomitant with a diagnosis of APL. Case report: Male patient, 30 years old, referred to the Hematology Department due to fever, odynophagia, intense adynamia, hyporexia, loss of 5 kg, night sweating, in addition to progressive dyspnea over one month. Laboratory exams were run with evidence of severe anemia, proceeding to etiological investigation with myelogram, which showed 84% of blasts, and immunophenotyping compatible with promyelocytic leukemia (APL), PML-RARA positive (90%). Also, presented ulcerated lesions in the genital region and right leg, whose biopsy showed proliferation of suspected round cells for infiltration by AML/GS. Immunohistochemistry confirmed GS. The patient underwent chemotherapy, with good response to the treatment and improvement of blood counts. Skin lesions evolved with healing. After the 3rd consolidation, PML-RARA was negative. Conclusion: This case report describes a rare presentation of a malignant hematological disease, GS, also known as skin chloroma. A diagnostic strategy including images, histopathology, immunohistochemistry and laboratory tests were needed for confirmation. Timely diagnosis is essential, so that appropriate treatment is instituted soon, benefiting the patient regarding survival and quality of life

Introducción: El sarcoma granulocítico (SG) es un tumor extramedular poco frecuente, compuesto por células mieloides inmaduras. Ocurre en 2% a 14% de los pacientes con leucemia mieloide aguda (AML). La asociación con leucemia promielocítica (LPA) es aún más rara, especialmente como manifestación en el momento del diagnóstico. El presente estudio expone el caso de un paciente con SG cutáneo que presenta un diagnóstico de LPA. Relato del caso: Paciente masculino de 30 años, remitido al Servicio de Hematología por fiebre, odinofagia, adinamia intensa, hiporexia, pérdida de 5 kg, sudoración nocturna, además de disnea progresiva a lo largo de un mes. Realizó exámenes de laboratorio con evidencia de anemia severa, continuando investigación etiológica con mielograma, que mostró 84% de blastos, e inmunofenotipificación compatible con LPA, PML-RARA positivo (90%). También presentaba lesiones ulceradas en región genital y muslo derecho, en las que la biopsia mostró proliferación de células redondas sospechadas para infiltración por LMA/SG. La inmunohistoquímica confirmó SG. El paciente fue sometido a quimioterapia, con buena respuesta al tratamiento y mejoría de los hemogramas. Las lesiones cutáneas evolucionaron con la curación. Después de la tercera consolidación, el PML-RARA fue negativo. Conclusión: Este reporte de caso describe una presentación poco común de una enfermedad hematológica maligna, el SG, también conocido como cloroma, en la piel. Se necesitaba una estrategia de diagnóstico que incluyera imágenes, histopatología, inmunohistoquímica y pruebas de laboratorio para confirmarlo. El diagnóstico oportuno es fundamental para que pronto se instaure el tratamiento adecuado

Association of oxidative stress and DNA damage with grafting time in patients with multiple myeloma and lymphoma submitted to autologous hematopoietic stem cell transplantation.

The aim of the study was to investigate the association between oxidative stress and DNA damage with grafting time in patients submitted to autologous hematopoietic stem-cell transplantation (HSCT). The study included 37 patients submitted to autologous HSCT diagnosed with Multiple Myeloma (MM) and lymphoma (Hodgkin's and non-Hodgkin's). Biomarkers of oxidative stress and DNA damage index (DI) were performed at baseline (pre-CR) of the disease and during the conditioning regimen (CR), one day after the HSCT, ten days after HSCT and twenty days after HSCT, as well as in the control group consisting of 30 healthy individuals. The outcomes showed that both groups of patients had an hyperoxidative state with high DI when compared to baseline and to the control group and that the CR exacerbated this condition. However, after the follow-up period of the study, this picture was re-established to the baseline levels of each pathology. The study patients with MM showed a mean grafting time of 10.75 days (8 to 13 days), with 10.15 days (8 to 15 days) for the lymphoma patients. In patients with MM, there was a negative correlation between the grafting time and the basal levels of GPx (r = -0.54; p = 0.034), indicating that lower levels of this important enzyme are associated with a longer grafting time. For the DI, the correlation was a positive one (r = 0.529; p = 0.030). In the group with lymphoma, it was observed that the basal levels of NOx were positively correlated with grafting time (r = 0.4664, p = 0.032). The data indicate the potential of these biomarkers as predictors of toxicity and grafting time in patients with MM and Lymphomas submitted to autologous HSCT.

Association of oxidative stress and DNA damage with grafting time in patients with multiple myeloma and lymphoma submitted to autologous hematopoietic stem cell transplantation / Associação do estresse oxidativo e dano ao DNA com o tempo de enxertia em pacientes com mieloma múltiplo e linfomas submetidos a transplante autólogo de células-tronco hematopoéticas

ABSTRACT The aim of the study was to investigate the association between oxidative stress and DNA damage with grafting time in patients submitted to autologous hematopoietic stem-cell transplantation (HSCT). The study included 37 patients submitted to autologous HSCT diagnosed with Multiple Myeloma (MM) and lymphoma (Hodgkin’s and non-Hodgkin’s). Biomarkers of oxidative stress and DNA damage index (DI) were performed at baseline (pre-CR) of the disease and during the conditioning regimen (CR), one day after the HSCT, ten days after HSCT and twenty days after HSCT, as well as in the control group consisting of 30 healthy individuals. The outcomes showed that both groups of patients had an hyperoxidative state with high DI when compared to baseline and to the control group and that the CR exacerbated this condition. However, after the follow-up period of the study, this picture was re-established to the baseline levels of each pathology. The study patients with MM showed a mean grafting time of 10.75 days (8 to 13 days), with 10.15 days (8 to 15 days) for the lymphoma patients. In patients with MM, there was a negative correlation between the grafting time and the basal levels of GPx (r = -0.54; p = 0.034), indicating that lower levels of this important enzyme are associated with a longer grafting time. For the DI, the correlation was a positive one (r = 0.529; p = 0.030). In the group with lymphoma, it was observed that the basal levels of NOx were positively correlated with grafting time (r = 0.4664, p = 0.032). The data indicate the potential of these biomarkers as predictors of toxicity and grafting time in patients with MM and Lymphomas submitted to autologous HSCT.

RESUMO O objetivo do estudo foi investigar a associação entre estresse oxidativo e dano ao DNA com o tempo de enxertia em pacientes submetidos ao transplante de células-tronco hematopoéticas autólogo (TCTH). Participaram do estudo 37 pacientes submetidos ao TCTH autólogo com diagnóstico de mieloma múltiplo (MM) e Linfomas (Hodgkin e não Hodgkin). Biomarcadores de estresse oxidativo e índice de dano ao DNA (ID) foram determinados no estado basal (Pré-RC) das doenças e durante o regime de condicionamento (RC), um dia após o TCTH, dez dias após o TCTH e vinte dias após o TCTH e no grupo controle composto por 30 individuos saudáveis. Os resultados demonstraram que os dois grupos de pacientes apresentaram um estado hiperoxidativo com elevado ID quando comparados ao estado basal e ao grupo controle e que o RC exacerbou essa condição. No entanto, após o tempo de acompanhamento do estudo, esse quadro foi reestabelecido ao estado basal de cada patologia. Os pacientes do estudo com MM apresentaram uma média do tempo de enxertia de 10,75 dias (8 a 13 dias), e de 10,15 dias (8 a 15 dias) para o grupo Linfoma. Nos pacientes com MM houve uma correlação negativa entre o tempo de enxertia e os níveis basais de GPx (r=-0,54; p=0,034), indicando que níveis mais baixos de GPx estão relacionados a um maior tempo de enxertia, e para o ID, a correlação foi positiva (r=0,529; p=0,030). No grupo com Linfoma, observou-se que os níveis basais de NOx correlacionaram-se positivamente com o tempo de enxertia (r= 0,4664; p=0,032). Os dados apontam para o potencial desses biomarcadores como preditores da toxicidade e do tempo de enxertia em pacientes com MM e Linfomas submetidos ao TCTH autólogo

T-cell/myeloid mixed-phenotype acute leukemia with monocytic differentiation and isolated 17p deletion.

Mixed phenotype acute leukemia is a rare subtype of leukemia that probably arises from a hematopoietic pluripotent stem cell. The co-expression of two of myeloid, B- or T-lymphoid antigens is the hallmark of this disease. Herein, the case of a 28-year-old female patient is reported who presented with hemoglobin of 5.8g/dL, white blood cell count of 138×10(9)/L and platelet count of 12×10(9)/L. The differential count of peripheral blood revealed 96% of blasts. Moreover, the patient presented with lymphadenopathy, splenomegaly and bone marrow infiltration by monocytoid blasts characterized as 7% positivity by Sudan Black cytochemical staining. Immunophenotyping revealed the involvement of blasts of both T- and monocytic lineages. The cytogenetic analysis showed an isolated 17p deletion. Thus, the diagnosis of T-cell/myeloid mixed phenotype acute leukemia was made with two particular rare features, that is, the monocytic differentiation and the 17p deletion as unique cytogenetic abnormalities. The possibility of concomitant expressions of T-cell and monocytic differentiation antigens in the same blast population is hard to explain using the classical model of hematopoiesis. However, recent studies have suggested that myeloid potential persists even when the lineage branches segregate toward B- and T-cells. The role of an isolated 17p deletion in the pathogenesis of this condition is unclear. At present, the patient is in complete remission after an allogeneic stem cell transplantation procedure.

T-cell/myeloid mixed-phenotype acute leukemia with monocytic differentiation and isolated 17p deletion

Mixed phenotype acute leukemia is a rare subtype of leukemia that probably arises from a hematopoietic pluripotent stem cell. The co-expression of two of myeloid, B- or T-lymphoid antigens is the hallmark of this disease. Herein, the case of a 28-year-old female patient is reported who presented with hemoglobin of 5.8 g/dL, white blood cell count of 138 × 109/L and platelet count of 12 × 109/L. The differential count of peripheral blood revealed 96% of blasts. Moreover, the patient presented with lymphadenopathy, splenomegaly and bone marrow infiltration by monocytoid blasts characterized as 7% positivity by Sudan Black cytochemical staining. Immunophenotyping revealed the involvement of blasts of both T- and monocytic lineages. The cytogenetic analysis showed an isolated 17p deletion. Thus, the diagnosis of T-cell/myeloid mixed phenotype acute leukemia was made with two particular rare features, that is, the monocytic differentiation and the 17p deletion as unique cytogenetic abnormalities. The possibility of concomitant expressions of T-cell and monocytic differentiation antigens in the same blast population is hard to explain using the classical model of hematopoiesis. However, recent studies have suggested that myeloid potential persists even when the lineage branches segregate toward B- and T-cells. The role of an isolated 17p deletion in the pathogenesis of this condition is unclear. At present, the patient is in complete remission after an allogeneic stem cell transplantation procedure...