Distinct relapse pattern across molecular ependymoma types

Abstract

Background. Ependymoma (EPN) is not a uniform disease but represents different disease types with biological and clinical heterogeneity. However, the pattern of when and where different types of EPN relapse is not yet comprehensively described. Methods. We assembled 269 relapsed intracranial EPN from pediatric (n = 233) and adult (n = 36) patients from European and Northern American cohorts and correlated DNA methylation patterns and copy-number alterations with clinical information. Results. The cohort comprised the following molecular EPN types: PF-EPN-A (n = 177), ST-EPN-ZFTA (n = 45), PF-EPN-B (n = 31), PF-EPN-SE (n = 12), and ST-EPN-YAP (n = 4). First relapses of PF-EPN-B (PF: posterior-fossa) and PF-EPN-SE (SE: subependymoma) occurred later than of PF-EPN-A, ST-EPN-YAP (ST: supratentorial), or ST-EPN-ZFTA (median time to relapse: 4.3 and 6.0 years vs. 1.9/1.0/2.4 years; P < .01). Metastatic or combined recurrences in PF-EPN-B and -A more often involved the spinal cord than in ST-EPN-ZFTA (72.7% and 40.0 vs. 12.5%; P