Progressively Metastasizing Ependymoma: Genomic Aberrations

Abstract

Ependymoma is the third most common childhood brain tumor. The outcome of patients is still determined by the level of surgical resection and metastatic status at diagnosis, and it has not improved significantly during the past decade. The following chapter will review the molecular biology of progressively metastatizing ependymoma. Metastatic disease, which is associated with particularly poor outcome, is a rare event in ependymoma, and both magnetic resonance imaging (MRI) and cytological evaluation of cerebrospinal fluid (CSF) are important tools to diagnose primary metastases. Over the last decades, few advances have been made in terms of survival of patients with metastastatic disease, due to the lack of understanding of the molecular basis of ependymoma progression and metastasis. Emerging data suggests that genomic aberrations accumulate during progression from localized to metastatic disease. Both balanced genomic profiles as well as specific changes such as 1q gain and/or homozygous deletion of CDKN2A in primary ependymomas may predispose to secondary metastatic dissemination. However, studies of larger cohorts are urgently needed in order to identify the specific molecular mechanisms involved in primary as well as secondary metastatic spread.