CBFA2T3-GLIS2 fusion transcript is a novel common feature in pediatric, cytogenetically normal AML, not restricted to FAB M7 subtype

Pediatric cytogenetically normal acute myeloid leukemia (CN-AML) is a heterogeneous subgroup of myeloid clonal disorders that do not harbor known mutations. To investigate the mutation spectrum of pediatric CN-AML, we performed whole-transcriptome massively parallel sequencing on blasts from 7 CN-AML pediatric patients. In 3 patients we identified a recurrent cryptic inversion of chromosome 16, encoding a CBFA2T3-GLIS2 fusion transcript. In a validation cohort of 230 pediatric CN-AML samples we identified 17 new cases. Among a total of 20 patients with CBFA2T3-GLIS2 fusion transcript out of 237 investigated (8.4%), 10 patients (50%) did not belong to the French-American-British (FAB) M7 subgroup. The 5-year event-free survival for these 20 children was worse than that for the other CN-AML patients (27.4% vs 59.6%; P = .01). These data suggest that the presence of CBFA2T3-GLIS2 fusion transcript is a novel common feature of pediatric CN-AML, not restricted to the FAB M7 subtype, predicting poorer outcome.