Abstract 2138: Complex copy number profiles in oligodendroglioma associate with anaplastic morphology and recurrence

Abstract

Abstract Oligodendroglioma (O) comprises approximately 6% of all diffuse gliomas (DG) and is associated with favorable outcome. It is characterized by the presence of 1p/19q full arm co-deletion and concurrent IDH mutations. Despite a general favorable outcome selected patients with Os experience repeated radiological and histological progression. Copy number aberrations in Os may highlight profiles that correlate with patient's outcome. Thirty-three Os from the files of our institution were profiled by immunohistochemistry, sequencing, and SNP-microarray. Pertinent clinical, pathological, and radiological data was collected. Descriptive statistics and survival analyses were performed. Median age at initial diagnosis was 39 (range:19-80 years). Male to female ratio=1.2. All tumors were supratentorial with most common location the frontal lobe (21/33, 64%). Six tumors were anaplastic (WHO grade III). Nine patients experienced tumor recurrence, of which 5 experienced multiple recurrences. Only one patient died after 9.8 years from initial diagnosis. The median follow-up time = 2.5 years (range:0.01-23.6). 21/33(63%), 9/33(27%), and 3/33(0.09%) underwent subtotal, gross total resection, or biopsy respectively. 48%(16/33) patients received chemotherapy and/or radiation therapy at initial diagnosis. Most tumors (28; 85%) had additional copy number aberrations most commonly involving chromosomes 11q, 12q, 9p, 4q, 3p, 11p. Chromosomal deletions/full-arm losses were more common than gains. Diploidy/tetraploidy was detected in 2 cases and chromothripsis in 1. Anaplastic and recurrent tumors had more complex copy numbers aberrations, including numerous loci of loss of heterozygosity. Statistical significance however was not reached. Additional copy number aberrations characterize Os. Complex copy number profiles associate with aggressive morphology and recurrence. Citation Format: Steve Lowe, Scott Lindhorst, David Cachia, Adriana Olar. Complex copy number profiles in oligodendroglioma associate with anaplastic morphology and recurrence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2138.