RESUMO
Acute myeloid leukemia (AML) is an aggressive hematologic neoplasia with a complex polyclonal architecture. Among driver lesions, those involving the FLT3 gene represent the most frequent mutations identified at diagnosis. The development of tyrosine kinase inhibitors (TKIs) has improved the clinical outcomes of FLT3-mutated patients (Pt). However, overcoming resistance to these drugs remains a challenge. To unravel the molecular mechanisms underlying therapy resistance and clonal selection, we conducted a longitudinal analysis using a single-cell DNA sequencing approach (MissionBioTapestri® platform, San Francisco, CA, USA) in two patients with FLT3-mutated AML. To this end, samples were collected at the time of diagnosis, during TKI therapy, and at relapse or complete remission. For Pt #1, disease resistance was associated with clonal expansion of minor clones, and 2nd line TKI therapy with gilteritinib provided a proliferative advantage to the clones carrying NRAS and KIT mutations, thereby responsible for relapse. In Pt #2, clonal architecture was less complex, and 1st line TKI therapy with midostaurin was able to eradicate the leukemic clones. Our results corroborate previous findings about clonal selection driven by TKIs, highlighting the importance of a deeper characterization of individual clonal architectures for choosing the best treatment plan for personalized approaches aimed at optimizing outcomes.
Assuntos
Compostos de Anilina , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda , Mutação , Inibidores de Proteínas Quinases , Análise de Célula Única , Estaurosporina , Tirosina Quinase 3 Semelhante a fms , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/genética , Análise de Célula Única/métodos , Inibidores de Proteínas Quinases/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Estaurosporina/análogos & derivados , Estaurosporina/uso terapêutico , Estaurosporina/farmacologia , Compostos de Anilina/uso terapêutico , Compostos de Anilina/farmacologia , Masculino , Pessoa de Meia-Idade , Feminino , Pirazinas/uso terapêutico , Pirazinas/farmacologia , Análise de Sequência de DNA/métodos , Proteínas Proto-Oncogênicas c-kit/genética , Proteínas Proto-Oncogênicas c-kit/antagonistas & inibidores , GTP Fosfo-Hidrolases/genética , Proteínas de Membrana/genética , Adulto , IdosoRESUMO
FMS-like tyrosine kinase 3 (FLT3) is among the most common driver genes recurrently mutated in acute myeloid leukemia (AML), accounting for approximately 30% of cases. Activating mutations of the FLT3 receptor include internal tandem duplications (ITD) that map to the auto-inhibitory juxtamembrane (JM) domain or point mutations within the tyrosine kinase domain (TKD). Several FLT3 tyrosine kinase inhibitors have been developed in the last few years, but midostaurin is currently the only one approved for the treatment of newly diagnosed patients harboring FLT3 mutations. Here we describe for the first time a novel in-frame deletion in exon 14 (JM domain) of the FLT3 gene, that we identified in a young woman with CBFb-MYH11-positive AML. We demonstrated that this novel FLT3 variant is pathogenic, since it is responsible for constitutive activation of FLT3 receptor. Finally, ex-vivo studies demonstrated that this novel mutation is sensitive to midostaurin.