Contrast enhancement in 1p/19q-codeleted anaplastic oligodendrogliomas is associated with 9p loss, genomic instability, and angiogenic gene expression

Abstract

BackgroundThe aim of this study was to correlate MRI features and molecular characteristics in anaplastic oligodendrogliomas (AOs).MethodsThe MRI characteristics of 50 AO patients enrolled in the French national network for high-grade oligodendroglial tumors were analyzed. The genomic profiles and IDH mutational statuses were assessed using high-resolution single-nucleotide polymorphism arrays and direct sequencing, respectively. The gene expression profiles of 25 1p/19q-codeleted AOs were studied on Affymetrix expression arrays.ResultsMost of the cases were frontal lobe contrast-enhanced tumors (52%), but the radiological presentations of these cases were heterogeneous, ranging from low-grade glioma-like aspects (26%) to glioblastoma-like aspects (22%). The 1p/19q codeletion (n = 39) was associated with locations in the frontal lobe (P =. 001), with heterogeneous intratumoral signal intensities (P =. 003) and with no or nonmeasurable contrast enhancements (P =. 01). The IDH wild-type AOs (n = 7) more frequently displayed ringlike contrast enhancements (P =. 03) and were more frequently located outside of the frontal lobe (P =. 01). However, no specific imaging pattern could be identified for the 1p/19q-codeleted AO or the IDH-mutated AO. Within the 1p/19q-codeleted AO, the contrast enhancement was associated with larger tumor volumes (P =. 001), chromosome 9p loss and CDKN2A loss (P =. 006), genomic instability (P =. 03), and angiogenesis-related gene expression (P