Background: The use of next-generation sequencing for fusion identification is being increasingly applied and aids our understanding of tumor biology. Some fusions are responsive to approved targeted agents, while others have future potential for therapeutic targeting. Although some pediatric central nervous system tumors may be cured with surgery alone, many require adjuvant therapy associated with acute and long-term toxicities. Identification of targetable fusions can shift the treatment paradigm toward earlier integration of molecularly targeted agents.
Methods: Patients diagnosed with glial, glioneuronal, and ependymal tumors between 2002 and 2019 were retrospectively reviewed for fusion testing. Testing was done primarily using the ArcherDx FusionPlex Solid Tumor panel, which assesses fusions in 53 genes. In contrast to many previously published series chronicling fusions in pediatric patients, we compared histological features and the tumor classification subtype with the specific fusion identified.
Results: We report 24 cases of glial, glioneuronal, or ependymal tumors from pediatric patients with identified fusions. With the exception of BRAF:KIAA1549 and pilocytic/pilomyxoid astrocytoma morphology, and possibly QKI-MYB and angiocentric glioma, there was not a strong correlation between histological features/tumor subtype and the specific fusion. We report the unusual fusions of PPP1CB-ALK, CIC-LEUTX, FGFR2-KIAA159, and MN1-CXXC5 and detail their morphological features.
Conclusions: Fusion testing proved to be informative in a high percentage of cases. A large majority of fusion events in pediatric glial, glioneuronal, and ependymal tumors can be identified by relatively small gene panels.
Keywords: CNS tumors; ependymoma; glioma; glioneuronal; molecular fusion; pediatric.
© 2019 Wiley Periodicals, Inc.