Functional polymorphisms of DNA repair genes in Latin America reinforces the heterogeneity of Myelodysplastic Syndrome

Abstract Nucleotide excision repair pathway (NER) is an essential mechanism for single-strand breaks (SSB) repair while xeroderma pigmentosum family (XPA to XPG) is the most important system to NER. Myelodysplastic syndrome (MDS) is a heterogeneous hematological cancer characterized by cytopenias and risk of acute myeloid leukemia (AML) transformation. MDS pathogenesis has been associated with problems of DNA repair system. This report aimed to evaluate NER polymorphisms (XPA rs1800975, XPC rs2228000, XPD rs1799793 and XPF rs1800067) in 269 MDS patients of different populations in Latin America (173 Brazilian and 96 Argentinean). Genotypes were identified in DNA samples by RT-qPCR using TaqMan SNP Genotyping Assay. Regarding rs1799793 polymorphism of XPD for Brazilian population, the heterozygous genotype AG presented a high odds ratio (OR) to have a normal karyotype (p= 0.012, OR=3.000) and the mutant homozygous genotype AA was associated to a high OR of AML transformation (p= 0.034, OR=7.4). In Argentine population, the homozygous mutant AA genotype of rs1800975 polymorphism of XPA was associated with an increased odd to have hemoglobin levels below 8g/dL (p= 0.013, OR=10.000) while for the rs1799793 polymorphism of XPD, the heterozygous AG genotype decreased OR to be classified as good (p< 0.001, OR=9.05 × 10−10), and intermediate (p< 0.001, OR=3.08 × 10−10), according to Revised-International Prognostic Scoring System. Regarding the rs1800067 polymorphisms of XPF, the homozygous mutant AA genotype showed a decreased OR to be classified as good (p< 0.001, OR=4.03 × 10−13) and intermediate (p< 0.001, OR=2.54 × 10−13). Our report reinforces the heterogeneity of MDS and demonstrates the importance of ethnic differences and regional influences in pathogenesis and prognosis of MDS.

Splicing factor SF3B1 mutations and ring sideroblasts in myelodysplastic syndromes: a Brazilian cohort screening study

ABSTRACT Background: Myelodysplastic syndromes (MDS) comprise a group of malignant clonal hematologic disorders characterized by ineffective hematopoiesis and propensity for progression to acute myeloid leukemia. Acquired mutations in the gene encoding RNA splicing factor 3B subunit 1 (SF3B1) are highly associated with the MDS subtypes presenting ring sideroblasts, and represent a specific nosological entity. The effects of these mutations on clinical outcomes are diverse and contrasting. Methods: A cohort of 91 Brazilian MDS patients, including patients with ring sideroblasts in the bone marrow, were screened for mutations in the SF3B1 hotspots (exons 12-15) by direct Sanger sequencing. Results: SF3B1 heterozygous mutations were identified in six patients (7%), all of them with ring sideroblasts, thus confirming the association between SF3B1 mutations and myelodysplastic syndrome subtypes bearing this morphologic feature (frequency of 6/13, p-value < 0.0001). Conclusion: This is the first screening of SF3B1 mutations in a cohort of Brazilian myelodysplastic syndrome patients. Our findings confirm that mutations in this splicing gene correlate with bone marrow ringed sideroblasts.

Chronic myeloid leukemia: an overview of the determinants of effectiveness and therapeutic response in the first decade of treatment with imatinib mesylate in a Brazilian hospital

Background: In the last decade, there has been a revolution in chronic myeloid leukemia treatment with the introduction of tyrosine kinase inhibitors with imatinib mesylate becoming the frontline therapy. Objective: To evaluate the therapeutic efficacy of imatinib mesylate in treating chronic myeloid leukemia patients and to identify factors related to therapeutic efficacy. Methods: This retrospective study was based on information obtained from patients'records in the Hematology Service of Hospital Universitário Walter Cantídio of the Universidade Federal do Ceará (HUWC / UFC). All patients diagnosed with chronic myeloid leukemia that took imatinib mesylate for a minimum of 12 months in the period from January 2001 to January 2011 were included. From a population of 160 patients, 100 were eligible for analysis. Results: The study population consisted of 100 patients who were mostly male (51%) with ages rangingbetween 21 and 40 years (42%), from the countryside (59%), in the chronic phase (95%), with high-riskprognostic factors (40%); the prognosis of high risk was not associated with complete hematologic responseor complete cytogenetic response, but correlated to complete molecular response or major molecularresponse. Reticulin condensation was associated with complete hematologic response and completecytogenetic response. It was found that 53% of patients had greater than 90% adherence to treatment. Thehigh adherence was correlated to attaining complete cytogenetic response in less than 12 months. Moreover,20% of patients had good response. Conclusion: Significant changes are indispensable in the monitoring of patients with chronic myeloid leukemia. Thus, the multidisciplinary team is important as it provides access to the full treatment and not just to medications. .

Avaliação das concentrações de malonaldeído e nitrito em pacientes com anemia falciforme em tratamento ou não com hidroxiureia / Evaluation of the concentration of malondialdehyde and nitrite in patients with sickle cell anemia treated or not with hydroxyurea

Objective: To determine the serum levels of malondialdehyde and nitrite in patients with sickle cell anemia treated or not with hydroxyurea in outpatient?s setting. Methods: Of the 65 patients with sickle cell anemia selected for the study, 51 of them were not treated with hydroxyurea (Group 1), 14 made chronic use of hydroxyurea (Group 2) and 20 individuals had no hemoglobinopathies (Control Group). Results: The Control Group had a lower and more homogeneous concentration of malondialdehyde levels as compared to the other groups. The results of Groups 1 and 2 showed increased values of malondialdehyde levels when compared to the Control Group. Considering the values of Groups 1 and 2, there were no significant changes in the malondialdehyde levels. There was no significant difference in the serum levels of nitrite between the groups. Group 2 presented a statistically significant correlation between serum malondialdehyde levels and the clinical variables investigated. In turn, Group 1 showed correlation only with occurrence of three or more vaso-occlusive crises. There was no correlation between nitrite levels and the clinical variables. Conclusion: The results revealed that during the pathogenesis of sickle cell anemia, an increase in lipid peroxidation was observed. On the other hand, no changes in oxidative parameters were detected during treatment with hydroxyurea, probably due to the short period of treatment of the patients studied.

Objetivo: Determinar os níveis séricos de malonaldeído e de nitrito em pacientes com anemia falciforme em tratamento ou não com hidroxiureia e em acompanhamento ambulatorial. Métodos: Dos 65 pacientes com diagnóstico de anemia falciforme selecionados para o estudo, 51 não fizeram tratamento com hidroxiureia (Grupo 1) e 14 fizeram uso crônico de hidroxiureia (Grupo 2), sendo que 20 indivíduos não tinham hemoglobinopatias (Grupo Controle). Resultados: O Grupo Controle possuía menor e mais homogênea concentração dos níveis de malonaldeído em relação aos outros grupos. Os resultados do Grupo 1 e do Grupo 2 mostraram valores aumentados dos níveis de malonaldeído quando comparados ao Grupo Controle. Quando comparados os valores dos Grupos 1 e 2, não foram observadas alterações significativas nos níveis de malonaldeído. Não houve diferença significativa nos níveis séricos de nitrito entre os grupos. Verificou-se que, no Grupo 2, houve uma correlação estatisticamente significativa dos níveis séricos de malonaldeído com as variáveis clínicas investigadas. Por sua vez, o Grupo 1 mostrou correlação somente com a ocorrência de três ou mais crises vaso-oclusivas. Não se verificou nenhuma correlação nos níveis de nitrito com as variáveis clínicas. Conclusão: Os resultados revelaram que, durante o estabelecimento da patogênese da anemia falciforme, pode ser observado um aumento na peroxidação lipídica. Por outro lado, durante o tratamento com a hidroxureia, não foi detectada nenhuma alteração nos parâmetros oxidativos, provavelmente devido ao curto período de tratamento dos pacientes em estudo.

Analysis of the association between Epstein-Barr virus and classic Hodgkins lymphoma in adult patients from Ceará (Brazil) by immunohistochemistry and in situ hybridization

The prevalence of Epstein-Barr virus (EBV) in patients with classical Hodgkins lymphoma (CHL) is geographically variable. In the present study the prevalence of EBV in CHL was assessed in adult patients from Ceará, Brazil. Thirty-seven cases were immunohistochemically evaluated for EBV using latent membrane protein (LMP1) antibody and for EBV latency-associated RNA (EBER1) using in situ hybridization (ISH). Sex and age did not differ among patients as to the frequency of CHL. Nodular sclerosis was the predominant histological subtype. LMP1 was found in Reed-Sternberg cells in 67.5 percent of the cases whereas ISH detected EBER1 in 75.6 percent. Regarding histological subtypes EBV infection rates were not found statistically different in nodular sclerosis (NS) and mixed cellularity (MC) subtypes (p = 0.66).

A freqüência do vírus Epstein-Barr (EBV) em pacientes com linfoma de Hodgkin Clássico (LHC) sofre variabilidade geográfica. No presente estudo investigamos a freqüência do EBV em pacientes com LHC no estado do Ceará. Trinta e sete casos de linfoma de Hodgkin clássico foram avaliados por imuno-histoquímica para EBV usando o anticorpo monoclonal contra a proteína latente da membrana (LMP1) e pelo método de hibridização in situ para RNA associado ao EBV (EBER1). Não há diferença por sexo e idade dos pacientes no que concerne à freqüência de LHC. O subtipo histológico esclerose nodular foi predominante. LMP1 esteve presente em células Reed-Sternberg em 67,5 por cento e pela hibridização in situ, através da sonda EBER, foi evidente em 75,6 por cento dos casos. Não observamos predominância significativa da associação de EBV com os subtipos histológicos esclerose nodular (EN) e celularidade mista (CM) (p = 0,66).