DNA methylation analysis of glioblastomas harboring FGFR3-TACC3 fusions identifies a methylation subclass with better patient survival

FGFR3-TACC3 (F3T3) fusions are seen in 3.1–11.7% of glioblastoma (GBM) cases with better survival [1, 4, 5, 7–9]. We endeavored to characterize methylation profles in detail, using a cohort of 79 F3T3-positive GBMs from 71 patients (seven patients with primary and recurrent tumor resections, Table S1). Compared to gliomas without a docu mented fusion, dimensionality reduction showed that F3T3- positive GBMs nested predominantly to GBM-mesenchymal and RTK-II subclasses (Fig. 1a). Transcriptomic analysis on 9 F3T3-positive and 31 negative patients (Fig. 1b) confrmed a previous fnding of activated mitochondrial activity and altered vascular activity [2, 6].