RESUMO
TET2, a member of the ten-eleven-translocation (TET) family genes that modify DNA by converting 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC), is located in chromosome 4q24 and is frequently mutated in myeloid malignancies. The impact of TET2 mutation on survival outcomes is still controversial; however, functional studies have proved that it is a loss-of-function mutation that impairs myeloid cell differentiation and contributes to the phenotype of myeloid neoplasia. We, herein, aimed to investigate TET2 expression in patients with myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). A significantly decreased TET2 expression was observed in bone marrow cells from AML (n = 53) and patients with MDS (n = 64), compared to normal donors (n = 22). In MDS, TET2 expression was significantly reduced in RAEB-1/RAEB-2 compared to other WHO 2008 classifications, and a lower TET2 expression was observed at the time of MDS disease progression in four of five patients. In multivariate analysis, low TET2 expression (P = 0.03), male gender (P = 0.02), and WHO 2008 classification (P < 0.0001) were independent predictors of poorer overall survival. These results suggest that defective TET2 expression plays a role in the MDS pathophysiology and predicts survival outcomes in this disease.
Assuntos
Anemia Refratária com Excesso de Blastos/genética , Anemia Sideroblástica/genética , Proteínas de Ligação a DNA/genética , Leucemia Mieloide Aguda/genética , Proteínas Proto-Oncogênicas/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anemia Refratária com Excesso de Blastos/diagnóstico , Anemia Refratária com Excesso de Blastos/mortalidade , Anemia Refratária com Excesso de Blastos/patologia , Anemia Sideroblástica/diagnóstico , Anemia Sideroblástica/mortalidade , Anemia Sideroblástica/patologia , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Estudos de Casos e Controles , Cromossomos Humanos Par 4 , Dioxigenases , Regulação para Baixo , Feminino , Expressão Gênica , Humanos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Mutação , Prognóstico , Análise de SobrevidaRESUMO
The WHO classification for myelodysplastic syndromes (MDS) has introduced new categories with prognostic relevance. Our aim was to examine the predictive value of the WHO and the FAB classification compared to parameters of peripheral blood, bone marrow and IPSS. Clinical data, peripheral blood counts, bone marrow (BM) cytology and histology and survival were analyzed in consecutive newly diagnosed adult patients with MDS. All cases were diagnosed according to FAB criteria and reclassified by the WHO proposal. Among 150 patients entering the study median age was 58 years (12-90). According to FAB, 90 patients had refractory anemia (RA), 18 sideroblastic anemia, 34 refractory anemia with excess of blasts (RAEB), three RAEB-t and five chronic myelomonocytic leukemia. Using the WHO proposal, one half of the patients with RA changed category. One patient had the 5q-syndrome. There were 25 cases with refractory cytopenias with multilineage dysplasia (RCMD) and 23 WHO "unclassified". These last patients presented few cell atypias, favorable IPSS and a good survival as has been described for refractory cytopenias in pediatric MDS. Hypocellular BM was found in 24% of the patients. Karyotype was available in only 85 cases. In the univariate analysis, both classifications, hemoglobin values, hypercellular bone marrow and IPSS had an influence on survival. Using the bootstrap resampling as stability test for the model created by the multivariate analysis, the WHO classification entered the model in 73%, FAB in 38% and IPSS in only 7%. Therefore, in a setting with a high number of low-risk MDS, the WHO classification is the best predictor of survival of the patients.