RESUMO
We investigated the frequency, predictors, and evolution of acute lymphoblastic leukemia (ALL) in patients with CNS relapse and introduced a novel method for studying BCR-ABL1 protein variants in cDNA from bone marrow (BM) and cerebrospinal fluid (CSF) blast cells. A total of 128 patients were analyzed in two PETHEMA clinical trials. All achieved complete remission after imatinib treatment. Of these, 30 (23%) experienced a relapse after achieving complete remission, and 13 (10%) had an isolated CNS relapse or combined CNS and BM relapses. We compared the characteristics of patients with and without CNS relapse and further analyzed CSF and BM samples from two of the 13 patients with CNS relapse. In both patients, classical sequencing analysis of the kinase domain of BCR-ABL1 from the cDNA of CSF blasts revealed the pathogenic variant p.L387M. We also performed ultra-deep next-generation sequencing (NGS) in three samples from one of the relapsed patients. We did not find the mutation in the BM sample, but we did find it in CSF blasts with 45% of reads at the time of relapse. These data demonstrate the feasibility of detecting BCR-ABL1 mutations in CSF blasts by NGS and highlight the importance of monitoring clonal evolution over time.
Assuntos
Sistema Nervoso Central/patologia , Proteínas de Fusão bcr-abl/genética , Mutação , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogênicas c-abl/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Viabilidade , Feminino , Proteínas de Fusão bcr-abl/sangue , Proteínas de Fusão bcr-abl/líquido cefalorraquidiano , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Avaliação de Resultados em Cuidados de Saúde , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-abl/líquido cefalorraquidiano , Proteínas Proto-Oncogênicas c-abl/química , RecidivaRESUMO
Despite central nervous system (CNS) prophylactic programs limit leptomeningeal involvement in acute lymphoblastic leukemia (ALL), it can still occur in a restricted percentage of cases. The exact risk rate remains still unknown, and several factors are associated with an increased probability to develop CNS involvement. Among them, Philadelphia (Ph)-positive genotype seems to play a relevant role. Recently, a flow cytometric assay to detect BCR-ABL protein has been developed, but little is known about its possible employment in leptomeningeal disease. Here, we show the miniaturized application of the original assay for BCR-ABL oncoprotein detection in cerebrospinal fluid (CSF) samples.
