RESUMO
ABSTRACT: T-cell lymphoblastic lymphoma (T-LBL) and T-cell acute lymphoblastic leukemia (T-ALL) have common and distinguishing clinical and molecular features. Molecular prognostic factors are needed for T-LBL. We assessed the prevalence and prognostic impact of the T-cell receptor ß (TRB)::NOTCH1 fusion in 192 pediatric patients with T-LBL and 167 pediatric patients with T-ALL, using novel multiplex polymerase chain reaction and genomic capture high-throughput sequencing techniques. The fusion was detected in 12 patients with T-LBL (6.3%) but in none of the patients with T-ALL (P = .0006, Fisher exact test). In T-LBL, the TRB::NOTCH1 fusion was associated with a significantly higher incidence of relapse (67% vs 17% in gene fusion-negative patients, P < .001, Fisher exact test). The breakpoint in TRB was most frequently located in J2-7 (n = 6). In NOTCH1, the breakpoints varied between exon 24 and 27. Consequently, a truncated NOTCH1 with its dimerization, regulation, and signal transduction domains gets controlled by strong TRB enhancer elements. This study reveals a novel recurrent genetic variant with significant prognostic relevance in T-LBL, which was absent in T-ALL. The TRB::NOTCH1 fusion in T-LBL suggests a possible unique pathogenic mechanism divergent from T-ALL. Further studies will validate the role of the TRB::NOTCH1 fusion as prognostic marker in T-LBL and elucidate its pathogenic mechanisms.
Assuntos
Proteínas de Fusão Oncogênica , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Receptor Notch1 , Humanos , Criança , Receptor Notch1/genética , Masculino , Feminino , Adolescente , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/mortalidade , Proteínas de Fusão Oncogênica/genética , Pré-Escolar , Prognóstico , LactenteRESUMO
Frequency, distribution and prognostic meaning of ALK-partner genes other than NPM1 in ALK-positive anaplastic large-cell lymphoma (ALCL) are unknown. Forty-nine of 316 ALCL diagnosed in the NHL-BFM study group showed no nuclear ALK expression suggestive of a variant ALK-partner; 41 were analysed by genomic capture high-throughput sequencing or specific RT-PCRs. NPM1::ALK was detected in 13 cases. Among the 28 patients with a non-NPM1::ALK-fusion partner, ATIC (n = 8; 29%) and TPM3 (n = 9; 32%) were the most common. Five of eight patients with ATIC::ALK-positive ALCL relapsed, none of nine with TPM3::ALK. Variant ALK-partners are rare and potentially associated with different prognoses.