PATH-10. EFFECTS OF 19q-LOSS IN IDH-MUTATED ASTROCYTOMAS ON BETTER PROGNOSIS AND OLIGODENDROGLIOMA-LIKE MORPHOLOGY

• Published in: Neuro-oncology (Charlottesville, Va.) Vol. 22; no. Supplement_2; pp. ii165 - ii166
• Main Authors: Otani, Ryohei, Uzuka, Takeo, Higuchi, Fumi, Matsuda, Hadzki, Tanaka, Shota, Mukasa, Akitake, Kim, Phyo, Ueki, Keisuke
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 09-11-2020
• Subjects: Molecular Pathology & Classification
• ISSN: 1522-8517; 1523-5866
• DOI: 10.1093/neuonc/noaa215.692

Abstract
We previously reported that there was a subgroup of IDH-mutated astrocytomas harboring only 19q-loss showing oligodendroglioma-like morphology and significantly longer overall survival (OS) compared with 19q-intact astrocytomas. To further explore the biological characteristics of this possible subgroup and obtain insight into the mechanism of their clinical behavior, we compared gene expression pattern between five 19q-loss and five 19q-intact IDH-mutated astrocytomas by microarray analysis. Comparing expression level of each genes between 19q-loss and 19q-intact astrocytomas,136 up-regulated genes and 203 down-regulated genes were extracted. Gene expression patterns of 19q-loss astrocytomas were partially different from that of 19q-intact astrocytomas. More down-regulated genes distributed on 19q and 4p, and more up-regulated genes distributed on 4q. Multiple genes associated with stem cell maintenance were down-regulated in 19q-loss astrocytomas, and genes associated with glioma progression were differentially expressed. Comparing expression patterns among 19q-loss astrocytomas and other IDH-mutant glioma subgroups using TCGA datasets by t-SNE analysis revealed that expression pattern of 19q-loss astrocytomas did not shift to that of oligodendrogliomas with 1p/19q codeletion but were a subgroup in astrocytomas. These results indicated that 19q-loss in astrocytomas was an acquired event different from 1p/19q codeletion in oligodendrogliomas, and better prognosis morphological features in 19q-loss astrocytomas were derived from differentially expressed genes associated with stem cell maintenance and glioma progression.