Posterior fossa ependymoma: current insights

Yuan Y. Thompson, Vijay Ramaswamy, Phedias Diamandis, Craig Daniels, Michael D. Taylor

Ependymoma is the third most common malignant tumor of the posterior fossa and is a major cause of neurological morbidity and mortality in children. Current treatments, particularly surgery and external beam irradiation result in relatively poor outcomes with significant neurological and cognitive sequelae from treatment. Historical approaches have considered all ependymomas as similar entities based on their morphological appearance. Recent advances in genomics and epigenetics have revealed, however, that ependymomas from different CNS locations represent distinct entities. Moreover, ependymoma of the posterior fossa, the most common location in children, is actually comprised of two distinct molecular variants. These two variants have marked differences in demographics, transcriptomes, structure, methylation patterns, and clinical outcomes. This allows for the development of new biology-based clinical risk stratification, which can both prioritize patients for de-escalation of therapy and identify those who will benefit from novel therapeutic strategies. Indeed, the identification of these two variants allows an opportunity for robust preclinical modeling for development of novel therapeutic strategies. Herein, we have summarized our current clinical approach to diagnosis and treatment of posterior fossa ependymoma, recent advances in understanding the biology of posterior fossa ependymoma and how these new insights can be translated into the clinic to form the basis of the next generation of clinical trials.