Deleveraging risk

Deleveraging risk is the risk attributable to investing in a security held by levered investors. When there is an aggregate negative shock to the availability of funding capital, securities with a greater presence of levered investors experience extreme return realizations as these investors unwind their positions. Using data on equity loans as a proxy for the degree of levered positions in a given stock, we find robust evidence of deleveraging risk. Stocks with a high degree of short selling experience large positive returns and a decrease in short selling around periods of funding capital scarcity

Chronic eosinophilic leukemia with a FIP1L1-PDGFRα fusion: case report and literature review

Chronic eosinophilia is habitually associated with allergic, infectious, inflammatory, neoplastic and endocrine conditions and exposure to certain drugs and toxic agents. However, eosinophilic proliferation may be primary, without identifiable causes, or provoked by clonal hematopoietic stem cell proliferation. Gene fusions involving PDGFR-α, PDGFR-β, and FGFR1 predispose patients to rare conditions with chronic myeloproliferation or lymphoproliferation, alterations in peripheral blood and bone marrow and diffuse tissue injury due to the release of cytokines and humoral factors from eosinophilic granules. The presence of the PDGFR-α rearrangement is commonly related to chronic eosinophilic leukemia, with alterations in peripheral mastocytes and neutrophils, and rarely to acute myeloid leukemia or T lymphoblastic lymphoma with eosinophilia. The most prevalent PDGFR-α rearrangement is one resulting from an interstitial deletion in the long arm of chromosome 4, that allows the formation of a neogene from the fusion of the FIP1L1 and PDGFRα genes. This codes a constitutively active tyrosine kinase, which can be inhibited by imatinib mesylate. In 2002, the successful treatment of a patient using imatinib to treat hypereosinophilic syndrome was reported. Since then, this drug has been utilized with fast, complete and lasting clinical responses. Here we describe a case of chronic eosinophilic syndrome with expression of the FIP1L1-PDGFR-α rearrangement.A eosinofilia no sangue e em tecidos está habitualmente associada a condições alérgicas, infecciosas, inflamatórias, neoplásicas, endocrinológicas, uso de medicamentos e exposição a agentes tóxicos. No entanto, pode ocorrer proliferação eosinofílica primária, sem causa aparente ou por expansão clonal da célula-tronco hematopoética. As neoplasias mielo ou linfoproliferativas associadas a rearranjos gênicos como PDGFRα, PDGFRβ e FGFR1 constituem condições raras nas quais ocorre mieloproliferação crônica, alterações no sangue periférico e na medula óssea e lesão tecidual de diferentes órgãos, a partir da liberação de citocinas e fatores humorais pelos grânulos eosinofílicos. A presença do rearranjo PDGFRα relaciona-se comumente à leucemia eosinofílica crônica, com envolvimento de mastócitos e neutrófilos e, mais raramente, à leucemia mielóide aguda ou ao linfoma linfoblástico T, com eosinofilia. O rearranjo PDGFRα mais comum é aquele resultante da deleção intersticial no braço longo do cromossomo 4, que permite a formação de um neogene a partir da fusão dos genes FIP1L1 e PDGFRα. Este codifica uma tirosino-quinase constitutivamente ativa que é inibida pelo mesilato de imatinibe. Em 2002 foi relatado o uso bem sucedido de mesilato de imatinibe em baixas doses em um paciente com síndrome hipereosinofilica e, desde então, vem-se utilizando esta droga com respostas clínicas rápidas, completas e duradouras. Descrevemos um caso de LEC com expressão do rearranjo FIP1L1-PDGFRα.Universidade Federal de São Paulo (UNIFESP) EPMHospital do Servidor Público Municipal de São PauloHospital Guilherme Álvaro UNIFESPUNIFESPUNIFESP, EPMHospital Guilherme Álvaro UNIFESPSciEL

Acute Myeloid Leukemia t(8;21) after treatment for hyperthyroidism using radioactive iodine: Secondary Leukemia?

Acute leukemia following treatment with Iodine131 is a rare event. The possible carcinogenic effect of Iodine131 is still not clear and a large series of cases did not show an increased incidence of cancer. A case of AML t(8;21), three years after Iodine131 treatment for hyperthyroidism, is reported. Secondary AML with t(8;21) is described following exposure to drugs that target topoisomerase II and radiotherapy. The controversial potential of Iodine131 as a leukemogenic agent and the fact that t(8;21) is also found in de-novo AML, emphasize the problem in establishing a relationship between these events although this potential can not be ruled out.Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM)UNIFESP, EPMSciEL

Immunophenotypic characterization of plasma cells in patients with multiple myeloma

INTRODUCTION AND OBJECTIVE: Multiple myeloma is an incurable malignancy characterized by the proliferation of a single clone of plasma cells in bone marrow. The aim of this study was to evaluate the frequency and prognostic value of the expression of aberrant phenotypes in patients with multiple myeloma by multiparametric flow cytometry. METHODS: The study was carried out at Department of Hematology and Hemotherapy of Federal University of São Paulo and 30 patients with MM were analyzed prospectively. In an attempt to identify myeloma cells by flow cytometry (FACSCalibur, BD), specific monoclonal antibodies anti-CD138, anti-CD38 and anti-CD45 were used for the selection of plasma cells. The control group comprised four healthy bone marrow donors. RESULTS: All myeloma plasma cells expressed at least one aberrant phenotype and CD56+++, CD117++, CD33++, CD13++ and CD28++ markers were more frequently observed in 88% of patients. Lymphoid markers were found in cases with a higher number of aberrant phenotypes. DISCUSSION: CD56+++ and CD28++ antigens showed high levels of β2-microglobulin, which are associated with more aggressive stages of the disease and larger tumor mass. The absence of adhesion molecule CD56 was associated with high levels of β2M and calcium ion, showing that this finding may have prognostic value. CONCLUSION: From this study it was concluded that the aberrant phenotypes are present in most cases of MM, and immunophenotyping by multiparametric flow cytometry is a useful tool to distinguish normal plasma cells from myeloma plasma cells.INTRODUÇÃO E OBJETIVO: O mieloma múltiplo (MM) é uma doença maligna incurável caracterizada pela proliferação de um único clone de plasmócitos na medula óssea. O objetivo deste estudo foi avaliar a frequência e o valor prognóstico da expressão dos fenótipos aberrantes em pacientes com MM por meio de citometria de fluxo multiparamétrica. MÉTODOS: O estudo foi realizado no Hospital São Paulo/Disciplina de Hematologia e Hemoterapia da Universidade Federal de São Paulo (UNIFESP), sendo analisados de maneira prospectiva 30 pacientes portadores de MM ao diagnóstico. Na tentativa de identificar as células mielomatosas por citometria de fluxo (FACScalibur, BD), foram utilizados anticorpos monoclonais anti-CD138, anti-CD38, anti-CD45 específicos para seleção dos plasmócitos. O grupo controle consistiu em quatro doadores saudáveis de medula óssea. RESULTADOS: Todos os plasmócitos mielomatosos expressaram pelo menos um fenótipo aberrante, e CD56+++, CD117++, CD33++, CD13++, CD28++ foram os marcadores mais frequentes, observados em 88% dos pacientes. Os marcadores linfoides foram encontrados nos casos com maior número de fenótipos aberrantes. DISCUSSÃO: Os antígenos CD56+++ e CD28++ apresentaram altos níveis de β2-microglobulina, sendo estes associados a estágios mais agressivos da doença e maior massa tumoral. A ausência da molécula de adesão CD56 foi relacionada com altos níveis de β2M e de cálcio iônico, mostrando que este achado pode ter valor prognóstico. CONCLUSÃO: A partir deste estudo concluiu-se que os fenótipos aberrantes estão presentes na maioria dos casos de MM e que a imunofenotipagem por citometria de fluxo multiparamétrica é uma boa ferramenta para distinguir células plasmáticas normais dos plasmócitos mielomatosos.Universidade Federal de PernambucoCentro de Estudos Superiores de Maceió Faculdade de Ciências Biológicas e da SaúdeUNIFESPUNIFESPSciEL

High incidence of chromosomal numerical abnormalities by multicentromeric FISH in multiple myeloma patients

This study aimed to characterize genetic alterations by interphase multicentromeric FISH focusing on chromosomal numerical abnormalities and using some locus specific probes for the most frequent aberrations found in the disease, in a homogeneous cohort of 34 advanced stage, but recently diagnosed MM patients; 97% had numerical chromosomal abnormalities detected by FISH, being 75% hyperdiploid, 18% hypodiploid and 3% tri/tetraploid. Using locus specific probes, we found 13q deletion in 30% and IGH rearrangement in 25% of cases. Grouping hypodiploid patients together with del13q (unfavorable group) and comparing them to the remaining cases (non unfavorable group) we found a trend towards younger patients presenting more unfavorable abnormalities (p = 0.06) and significant lower hemoglobin level (Hb < 8.5 mg/dl, p = 0.03).Este estudo objetivou detectar as alterações genéticas em pacientes com mieloma múltiplo (MM), usando o método de hibridação in situ por fluorescência em interfases (FISH interfásico). Para detectar as alterações numéricas foram usadas sondas multicentroméricas e para os rearranjos mais freqüentemente observados na doença foram utilizadas as sondas lócus específicas para IGH, P53, ciclina D1 e RB1. Foram estudados 34 pacientes com MM em estágio avançado, ainda que recém-diagnosticados, 97% dos quais apresentaram anormalidades numéricas detectadas por FISH, sendo 75% hiperdiplóides, 18% hipodiplóides e 3% tri/tetraplóides. Em relação às demais anormalidades, a deleção 13q foi encontrada em 30% dos casos e o rearranjo IGH, em 25%. Agrupando os pacientes com hipodiploidia e com deleção 13q14 (grupo desfavorável) e comparando-os com os demais (grupo não-desfavorável), houve tendência a pacientes jovens no grupo desfavorável (p = 0,06) e níveis de hemoglobina (Hb) significativamente mais baixos (< 8,5 g/dl, p = 0,03).Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

Leucemia linfocítica crônica: anormalidades cromossômicas e a sua relação com o estágio clínico CD38 e o ZAP-70

Chronic lymphocytic leukemia is the most prevalent type of leukemia in the West. It is characterized by an extremely variable clinical course. The aim of the study was to detect the most frequent chromosomal abnormalities in patients with CLL using FISH, and assess them regarding age, gender, clinical stage and CD38 and ZAP-70 expressions. We found 51.7% of the patients with chromosome abnormalities. The most frequent one was del 13q14 in 34.5% of cases. It was associated to other alterations in 17.2%. 17p13 deletions were found in 17.2% and trisomy 12 in 13.8% (in isolation in 6.9% and associated to del 13q14, in 6.9% of the cases). An 11q22 deletion was found in one case associated to a 13q14 deletion. To better evaluate the relationship between chromosome aberrations and other prognostic factors in CLL, two cytogenetics groups were considered: favorable (13q deletion in isolation and no alteration) and unfavorable outcomes (trisomy 12, 17p13 deletion, 11q22 deletion and two simultaneous alterations).The unfavorable alterations were more frequently seen among young individuals (<60y). There were more females (70%) than males in this group (p=0.04). In relation to the Binet's staging system, patients with unfavorable cytogenetic alterations, tended to be B and C stages, while in the favorable group prevailed patients in stage A. Additionally, patients with poor prognostic cytogenetics tended to express CD38 and ZAP-70 proteins.A leucemia linfocítica crônica (LLC) é o tipo de leucemia mais prevalente no Ocidente e é caracterizada por curso clínico extremamente variável. O objetivo deste estudo foi detectar as anomalias cromossômicas mais freqüentes em pacientes com LLC, empregando a técnica FISH, e correlacioná-las com idade, sexo, estádio clínico, expressão de CD 38 e ZAP-70. Foram encontradas alterações cromossômicas em 51,7% dos pacientes. A mais freqüente foi a del 13q14, observada em 34,5% dos casos e que esteve associada a outras anomalias em 17,2%. Deleção 17p13 foi encontrada em 17,2% e trissomia 12 em 13,8% (isolada em 6,9% e associada à del 13q14 em 6,9%). Deleção 11q22 foi observada em um caso em concomitância à del 13q14. Para melhor avaliar a relação entre alteração cromossômica e outros fatores prognósticos em LLC, dois grupos citogenéticos foram considerados: favorável (deleção 13q isolada e ausência de alterações) e desfavorável (trissomia 12, deleção 17p13, deleção 11q22 e duas anomalias simultâneas). As alterações desfavoráveis foram mais freqüentemente observadas em indivíduos jovens (<60 anos) e em mulheres (70%)(p=0,04). Em relação ao sistema de estadiamento de Binet, houve tendência dos pacientes com alterações cromossômicas desfavoráveis apresenteram-se nos estágios B e C enquanto no grupo favorável prevaleceram aqueles com estágio A. Em adição, pacientes com achados citogenéticos de prognóstico desfavorável tiveram tendência a expressar proteínas CD 38 e ZAP-70.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

Reduced SLIT2 is Associated with Increased Cell Proliferation and Arsenic Trioxide Resistance in Acute Promyelocytic Leukemia

Simple Summary In solid tumors, the altered expression of embryonic genes such as the SLIT-ROBO family has been associated with poor prognosis, while little is known about their role in acute myeloid leukemia (AML). Previous studies reported frequent hypermethylation of SLIT2 mediated by the methyltransferase enzyme EZH2 and more recently the PML protein, which are commonly found to be aberrantly expressed in AML. Here, we aim to assess retrospectively the clinical relevance of the SLIT2 gene in acute promyelocytic leukemia, a homogenous subtype of AML. We demonstrated that reduced SLIT2 expression was associated with high leukocyte counts and reduced overall survival in different APL cohorts. STLI2 treatment decreased APL growth, while SLIT2 knockdown accelerated cell cycle progression and proliferation. Finally, reduced expression of SLIT2 in murine APL blasts resulted in fatal leukemia associated with increased leukocyte counts in vivo. These findings demonstrate that SLIT2 can be considered as a prognostic marker in APL, and a potential candidate for clinical studies of a more heterogeneous disease, such as AML. The SLIT-ROBO axis plays an important role in normal stem-cell biology, with possible repercussions on cancer stem cell emergence. Although the Promyelocytic Leukemia (PML) protein can regulate SLIT2 expression in the central nervous system, little is known about SLIT2 in acute promyelocytic leukemia. Hence, we aimed to investigate the levels of SLIT2 in acute promyelocytic leukemia (APL) and assess its biological activity in vitro and in vivo. Our analysis indicated that blasts with SLIT2(high) transcript levels were associated with cell cycle arrest, while SLIT2(low) APL blasts displayed a more stem-cell like phenotype. In a retrospective analysis using a cohort of patients treated with all-trans retinoic acid (ATRA) and anthracyclines, high SLIT2 expression was correlated with reduced leukocyte count (p = 0.024), and independently associated with improved overall survival (hazard ratio: 0.94; 95% confidence interval: 0.92-0.97; p <0.001). Functionally, SLIT2-knockdown in primary APL blasts and cell lines led to increased cell proliferation and resistance to arsenic trioxide induced apoptosis. Finally, in vivo transplant of Slit2-silenced primary APL blasts promoted increased leukocyte count (p = 0.001) and decreased overall survival (p = 0.002) compared with the control. In summary, our data highlight the tumor suppressive function of SLIT2 in APL and its deteriorating effects on disease progression when downregulated