This retrospective multi-center study confirmed that MEF2D fusions are associated with female sex, older age and atypical immunophenotype. The most common fusion partners were BCL9 and HNRNPUL1, accounting for >80% cases.
We have confirmed previous studies that suggest a high risk of relapse for patients with MEF2D::BCL9 fusions, but we could not confirm that this poor outcome extended to patients with other MEF2D partners.