Multiparametric flow cytometry directing the evaluation of CRLF2 rearrangements and JAK2 status in pediatric B cell precursor acute lymphoblastic leukemia

Asbtract Introduction This study aimed to determine whether cytokine receptor-like factor 2 (CRLF2) antigen expression evaluated using multiparametric flow cytometry (MFC) could predict the genotype of CRLF2 and Janus kinase 2 (JAK2) status for application in the diagnosis of pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Methods A total of 321 BCP-ALL bone marrow samples were collected, 291 at diagnosis and 13 at first relapse, while 17 samples were excluded due to low cellular viability. The CRLF2 antigen expression was evaluated using flow cytometry (percentage of positivity and median fluorescence intensity [MFI]). The CRLF2 transcript levels were assessed via quantitative reverse transcription polymerase chain reaction using SYBR Green. The CRLF2 rearrangements (CRLF2-r) were identified using the CRLF2 break-apart probe via fluorescence in situ hybridization. Sanger sequencing was performed to identify the JAK2 exon 16 mutations. Results We observed that 60 of the 291 cases (20.6%) presented CRLF2 antigen positivity, whereas the CRLF2 transcript overexpression was found in 19 of 113 cases (16.8%). The JAK2 mutation was found in four out of 116 cases (3.4%), all of which had CRLF2 ≥10% of positive cells and intermediate or high MFI (p < 0.0001). In addition, in the 13 cases with the CRLF2-r, a positive correlation was found with the CRLF2 antigen intermediate (61.5%) MFI (p= 0.017). Finally, the CRLF2-positive antigen was identified in the BCP-ALL subclones. Conclusion The identification of the CRLF2 antigen using the MFC, based on the percentage of positivity and MFI values, is a useful tool for predicting JAK2 mutations and CRLF2-r.

Identification of the MYST3-CREBBP fusion gene in infants with acute myeloid leukemia and hemophagocytosis

ABSTRACT Background: Acute myeloid leukemia presenting the MYST3-CREBBP fusion gene is a rare subgroup associated with hemophagocytosis in early infancy and monocytic differentiation. The aim of this study was to define the relevant molecular cytogenetic characteristics of a unique series of early infancy acute myeloid leukemia cases (≤24 months old), based on the presence of hemophagocytosis by blast cells at diagnosis. Methods: A series of 266 infant cases of acute myeloid leukemia was the reference cohort for the present analysis. Acute myeloid leukemia cases with hemophagocytosis by blast cells were reviewed to investigate the presence of the MYST3-CREBBP fusion gene by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction. Results: Eleven cases with hemophagocytosis were identified with hemophagocytic lymphohistiocytosis being ruled out. Six cases were classified as myelomonocytic leukemia, three as AML-M7 and two as AML-M2. In five cases, the presence of the MYST3-CREBBP fusion gene identified by molecular cytogenetics was confirmed by fluorescence in situ hybridization. All patients received treatment according to the Berlin-Frankfürt-Münster acute myeloid leukemia protocols and only one out of the five patients with the MYST3-CREBBP fusion gene is still alive. Conclusions: Our findings demonstrate that the presence of hemophagocytosis in acute myeloid leukemia was not exclusively associated to the MYST3-CREBBP fusion gene. Improvements in molecular cytogenetics may help to elucidate more complex chromosomal rearrangements in infants with acute myeloid leukemia and hemophagocytosis.

Perfil imunofenotípico e molecular das leucemias agudas de células-T pediátricas / [Immunophenotypic and molecular profile of acute pediatric T-cell leukemias]

Introdução: Leucemia linfoblástica de células-T (LLA-T) é uma doença heterogênea que representa de10-15% das LLA pediátricas. Diversas alterações como fusões gênicas envolvendo fatores de transcriçãoe mutações em proto-oncogenes estão associadas às LLAs-T sem, contudo, haver consenso no valorprognóstico. Objetivos: Avaliar possíveis associações dos diferentes perfis maturativos, bem como aexpressão celular do CD127, CD135 e CD117, às alterações somáticas em LLA-T (Mutação em IL-7R,FLT3, FBXW7, NOTCH1, N-KRAS e rearranjos gênicos STIL-TAL1 e TLX3) e a influência na sobrevidalivre de eventos (SLE). Material e Métodos: 189 pacientes (< 19 anos) com LLA-T foram avaliadosquanto ao perfil imunofenotípico, incluindo marcadores como CD127, CD135 e CD117 pela citometriade fluxo multiparamétrica (CFM). Mutações e fusões gênicas foram identificadas por testes moleculares(PCR, sequenciamento direto e RT-PCR). Foram analisadas as sobrevidas global (SG) e sobrevida livrede eventos (SLE), em cinco anos, pelo método de Kaplan-Meier e diferenças entre os grupos foramcomparadas pelo teste de log-rank. Para avaliação da distribuição das variáveis categóricas utilizou-seo teste exato de Fisher ou Qui-quadrado. Para a comparação de variáveis contínuas utilizou-se os testesnão paramétricos de Mann-Whitney ou Kruskal wallis. P valor < 0,05 foi considerado estatisticamente significante...

T-cell Acute Lymphoblastic Leukemia (T-ALL) is a heterogeneous and aggressive disease that represents 10-15% of childhood ALL. Several alterations such as fusion genes involving transcription factors and mutations in proto-oncogenes are associated with T-ALL, however, without consensus in outcome. Aim: To evaluate the association among different maturation profiles, as well as the cellular expression of CD127, CD135 and CD117, to somatic alterations in T-ALL (mutations in IL7R, FLT3, FBXW7, NOTCH1, N-KRAS and STIL-TAL1 and TLX3 gene rearrangements) and influence in eventfree survival (EFS). Methods: A cohort of 189 T-ALL cases (<19 years old) were evaluated in relation to the immunophenotype profile, including the CD127, CD135 and CD117 markers by multiparametricflow cytometry (MFC). Mutations and fusion genes were identified according to standard molecular techniques (PCR, direct sequencing and RT-PRC). The overall survival (OS) and event-free survival (EFS), in five years, were analyzed by the Kaplan-Meier method and differences among the groups werecompared by log-rank test. To evaluate the distribution of categorical variables, the Fisher´s exact test or chi-square test were used. To compare continuous variables the non-parametric tests, Mann-Whitney or Kruskal wallis, were used. P values < 0.05 were considered statistically significant...

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.

Avaliação do Programa Nacional de Triagem Neonatal para Hemoglobinopatias / Assessment of National Neonatal Screening Program for Hemoglobinopathies

As hemoglobinopatias representam grave problema de saúde pública em virtude de alta freqüência e pelas consequências fisiopatogênicas. No presente estudo foi avaliado o Programa Nacional de Triagem Neonatal para hemoglobinopatias no Maranhão no ano de 2008. Utilizando-se relatórios obtidos do serviço de referência e Secretaria de Saúde do Estado, foram analisados os dados da implantação do programa em todos os municípios maranhenses, bem como a consonância com o Ministério da Saúde quanto aos recursos humanos e divulgação do serviço. Na coleta das amostras, 60,4% das crianças tinham entre oito dias a um mês de idade. O tempo médio entre a coleta e o recebimento da amostra foi de 37 dias. Foram realizados 99.498 testes para hemoglobinopatias, dos quais 4,8%apresentaram perfis alterados. A alteração mais frequente foi o traço falciforme (1/25,4). A coberturado programa foi de 81,57%. Conclui-se que há necessidade de melhorias no serviço de triagem quanto aos indicadores de gerenciamento, bem como maior atenção no diagnóstico e intervenção precoce das doenças hemoglobínicas que apresentam alta frequência no Maranhão.