RESUMO
Acute leukemia is the most common cancer in children and involves several factors that contribute to the development of multidrug resistance and treatment failure. According to our recent studies, the BAALC gene is identified to have high mRNA expression levels in childhood acute lymphoblastic leukemia (ALL) and those with multidrug resistance. Several polymorphisms are associated with the expression of this gene. To date, there has been no study on the rs62527607 [GT] single nucleotide polymorphism (SNP) of BAALC gene and its link with childhood acute lymphoblastic and myeloid leukemia (AML). The purpose of this study is to evaluate the prevalence of this polymorphism in pediatric acute leukemia, as well as its relationship with prognosis. DNA samples were extracted from bone marrow slides of 129 children with ALL and 16 children with AML. The rs62527607 [GT] SNP was evaluated using mismatch polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based analysis. The association between the SNP alleles and patient disease-free survival was then assessed. The prevalence of the T-allele of rs62527607 [GT] SNP in childhood T-ALL and pre-B-ALL was 28.3% and 11.2%, respectively. In the pre-B-ALL patients, 3 year disease free survival was associated with the GG genotype. Results showed a robust association between the rs62527607 SNP and the risk of relapse in ALL, but not AML, patients. T-ALL patients with the GT genotype had an 8.75 fold higher risk of relapse. The current study demonstrates a significant association between the genotype GT and the polymorphic allele G424T, and introduces this SNP as a negative prognostic factor in children with ALL.
Assuntos
Análise do Polimorfismo de Comprimento de Fragmentos Amplificados/métodos , Resistência a Múltiplos Medicamentos , Leucemia Mieloide Aguda/genética , Proteínas de Neoplasias/genética , Recidiva Local de Neoplasia/genética , Polimorfismo de Nucleotídeo Único , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Criança , Pré-Escolar , Intervalo Livre de Doença , Resistencia a Medicamentos Antineoplásicos , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Masculino , Prognóstico , Análise de SobrevidaRESUMO
BAALC is a novel molecular marker in leukemia that is highly expressed in patients with acute leukemia. Increased expression levels of BAALC are known as poor prognostic factors in adult acute myeloid and lymphoid leukemia. The purpose of the present study was to evaluate the prognostic significance of the BAALC gene expression levels in pediatric acute lymphoblastic leukemia (ALL) and its association with MDR1. Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), the mRNA expression levels of BAALC and MRD1 were measured in bone marrow samples of 28 new diagnosed childhood ALL patients and 13 children without cancer. Minimal residual disease (MRD) was measured one year after the initiation of the chemotherapy using the RT-qPCR method. The high level expression of BAALC had a significant association with the pre-B-ALL subtype, leukocytosis and positive MRD after one year of treatment in leukemic patients. In addition, a positive correlation between BAALC and MDR1 mRNA expression was shown in this group. In conclusion, to the best of our knowledge, the increase of BAALC expression as a poor prognostic factor for childhood ALL is shown for the first time. Additionally, the correlation between BAALC and MDR1 in mRNA expression levels can aid for an improved understanding of the mechanism through which BAALC may function in ALL and multidrug resistance.
