Genetic profile of T-cell acute lymphoblastic leukemias with MYC-translocations
Menée sur une cohorte de 196 patients atteints d'une leucémie aiguë lymphoblastique de lignée T (64 adultes, 132 enfants), cette étude analyse l'expression différentielle de 148 gènes en présence de translocations du gène MYC
MYC-translocations represent a genetic subtype of T-lineage acute lymphoblastic leukemia (T-ALL), which occurs at an incidence of approximately 6%, assessed within a cohort of 196 T-ALL patients (64 adults and 132 children). The translocations were of two types; those rearranged with the T-cell receptor loci (TCR) and those with other partners. MYC-translocations were significantly associated with the TAL/LMO subtype of T-ALL (p=0,018) and trisomies 6 (p<0,001) and 7 (p<0,001). Within the TAL/LMO subtype, gene expression profiling identified 148 differentially expressed genes between patients with and without MYC-translocations, specifically 77 were up- and 71 down- regulated in those with MYC-translocations. The poor prognostic marker, CD44, was among the up-regulated genes. MYC-translocations occurred as secondary abnormalities, present in sub-clones in half of cases. Longitudinal studies indicated an association with induction failure and relapse.