Polysomy is associated with poor outcome in 1p/19q codeleted oligodendroglial tumors

Neuro Oncol. 2019 Sep 6;21(9):1164-1174. doi: 10.1093/neuonc/noz098.

Abstract

Background: Chromosomal instability is associated with earlier progression in isocitrate dehydrogenase (IDH)-mutated astrocytomas. Here we evaluated the prognostic significance of polysomy in gliomas tested for 1p/19q status.

Methods: We analyzed 412 histologic oligodendroglial tumors with use of 1p/19q testing at 8 institutions from 1996 to 2013; fluorescence in situ hybridization (FISH) for 1p/19q was performed. Polysomy was defined as more than two 1q and 19p signals in cells. Tumors were divided into groups on the basis of their 1p/19q status and polysomy and were compared for progression-free survival (PFS) and overall survival (OS).

Results: In our cohort, 333 tumors (81%) had 1p/19q loss; of these, 195 (59%) had concurrent polysomy and 138 (41%) lacked polysomy, 79 (19%) had 1p/19q maintenance; of these, 30 (38%) had concurrent polysomy and 49 (62%) lacked polysomy. In agreement with prior studies, the group with 1p/19q loss had significantly better PFS and OS than did the group with 1p/19q maintenance (P < 0.0001 each). Patients with 1p/19q loss and polysomy showed significantly shorter PFS survival than patients with 1p/19q codeletion only (P < 0.0001), but longer PFS and OS than patients with 1p/19q maintenance (P < 0.01 and P < 0.0001). There was no difference in survival between tumors with >30% polysomic cells and those with <30% polysomic cells. Polysomy had no prognostic significance on PFS or OS in patients with 1p/19q maintenance.

Conclusions: The presence of polysomy in oligodendroglial tumors with codeletion of 1p/19q predicts early recurrence and short survival in patients with 1p/19q codeleted tumors.

Keywords: 1p/19q codeletion; glioma; oligodendroglioma; polysomy.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Aneuploidy*
  • Brain Neoplasms / genetics*
  • Brain Neoplasms / therapy
  • Chemotherapy, Adjuvant
  • Child
  • Chromosomal Instability
  • Chromosome Deletion
  • Chromosomes, Human, Pair 1 / genetics*
  • Chromosomes, Human, Pair 19 / genetics*
  • Female
  • Humans
  • In Situ Hybridization, Fluorescence
  • Isocitrate Dehydrogenase / genetics
  • Male
  • Middle Aged
  • Neoadjuvant Therapy
  • Neurosurgical Procedures
  • Oligodendroglioma / genetics*
  • Oligodendroglioma / therapy
  • Prognosis
  • Progression-Free Survival
  • Radiotherapy, Adjuvant
  • Survival Rate
  • Young Adult

Substances

  • IDH2 protein, human
  • Isocitrate Dehydrogenase
  • IDH1 protein, human