Rare and novel RUNX1 fusions in myeloid neoplasms: A single-institute experience

Chromosome translocations involving the RUNX1 gene at 21q22 are recurring abnormalities in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), that is, t(8;21) and t(3;21) and in B-cell acute lymphoblastic leukemia with t(12;21). These translocations result in the fusion of RUNX1 with RUNX1T1, MECOM, and ETV6, respectively, and are implicated in leukemogenesis. Here we describe 10 rare RUNX1 fusion gene partners, including six novel fusions, in myeloid neoplasia. Comprehensive molecular testing revealed the partner genes and features of these fusions in all the tested patients, and detected various recurring myeloid related gene mutations in eight patients. In two patients, RUNX1 mutations were identified. Most of these fusions were detected in patients with high-grade MDS and AML with a relatively short survival. Integration of conventional chromosome analysis, FISH testing and molecular genetic studies allow a comprehensive characterization of these rare RUNX1 fusions. Our study may help define myeloid neoplasms with rare and novel RUNX1 translocations and support appropriate patient management.