DNMT3A co-mutation in an IDH1-mutant glioblastoma

: Glioblastomas are highly aggressive, infiltrative, and genetically heterogeneous primary brain tumors that arise de novo or secondarily progress over time from low-grade tumors. Along with well-established signature mutational profiles, emerging research suggests that the epigenetic tumor landscape plays an important role in gliomagenesis via transcriptional regulation, DNA methylation, and histone modifications. The pursuit of targeted therapeutic approaches, based not only on expression profiles but also on somatic mutations, is fundamental to the effort of improving survival in patients with glioblastoma. Here, we describe a missense DNMT3A p.P904S mutation in an IDH1-mutant glioblastoma. Although never previously reported in gliomas, this mutation is predicted to be pathogenic and has been reported in several other malignancies. Our report suggests that elucidating epigenetic control is important to understanding glioblastoma biology and may likely unveil targets potentially important to glioblastoma treatment in an effort to improve survival.