CBFA2T3-GLIS2 fusion transcript is a novel common feature in pediatric, cytogenetically normal AML, not restricted to FAB M7 subtype
Masetti R, Pigazzi M, Togni M, Astolfi A, Indio V, Manara E, Casadio R, Pession A , Basso G, Locatelli F.
Department of Pediatrics, "Lalla Seragnoli", Hematology-Oncology Unit, University of Bologna, Italy
Pediatric cytogenetically-normal acute myeloid leukemia (CN-AML) is a heterogeneous subgroup of myeloid clonal disorders not harbouring known mutations. To investigate the mutation spectrum of pediatric CN-AML, we performed whole-transcriptome massively-parallel sequencing on bone marrow leukemia blasts of 7 CN-AML pediatric patients, identifying in 3 of them a recurrent cryptic inversion of chromosome 16, encoding a CBFA2T3-GLIS2 fusion transcript. We then screened a validation cohort of 230 pediatric CN-AML samples, identifying 17 new cases. Thus, we found 20 patients carrying the CBFA2T3-GLIS2 fusion transcript out of 237 investigated (8.4%); 10 of them (50%) did not belong to the FAB M7 subgroup. The 5-year event-free survival of these 20 children was worse than that of the other CN-AML patients (27.4% vs 59.6%, P=0.01). These data suggest that the presence of CBFA2T3-GLIS2 fusion transcript is a novel common feature of pediatric CN-AML, not restricted only to the FAB M7 subtype, predicting poorer outcome.