MRI Imaging Characteristics of Glioblastoma with Concurrent Gain of Chromosomes 19 and 20

Taejin L Min,Stewart G Neill,Jose E Velazquez Vega,Jason W Allen,Brent D Weinberg

doi:10.3390/tomography7020021

Taejin L Min, Stewart G Neill + Show 3 more

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https://doi.org/10.3390/tomography7020021

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Abstract

Glioblastoma (GBM) is the most common and deadly primary brain tumor in adults. Some of the genetic variations identified thus far, such as IDH mutation and MGMT promotor methylation, have implications for survival and response to therapy. A recent analysis of long-term GBM survivors showed that concurrent gain of chromosomes 19 and 20 (19/20 co-gain) is a positive prognostic factor that is independent of IDH mutation status. In this study, we retrospectively identified 18 patients with 19/20 co-gain and compared their imaging features to a control cohort without 19/20 co-gain. Imaging features such as tumor location, size, pial invasion, and ependymal extension were examined manually. When compared without further genetic subclassification, both groups showed similar imaging features except for rates of pial invasion. When each group was subclassified by MGMT promotor methylation status however, the two groups showed different imaging features in a number of additional ways including tumor location, size, and ependymal extension. Our results indicate that different permutations of various genetic mutations that coexist in GBM may interact in unpredictable ways to affect imaging appearance, and that imaging prognostication may be better approached in the context of the global genomic profile rather than individual genetic alterations.

Highlights

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults, with over 12,000 estimated new cases annually [1]
Mutation of isocitrate dehydrogenase (IDH) gene is associated with longer survival and O6-methylguanine-DNA methyltransferase promotor (MGMT) methylation is associated with improved response to therapy with temozolomide [6,7,8]
These tumors had similar imaging features compared to GBMs without the mutation when considered alone, when considering together with MGMT methylation, differences were apparent

Summary

Introduction

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults, with over 12,000 estimated new cases annually [1]. GBM has the worst prognosis of all primary brain tumors, with median overall survival estimated at 15.6 months [2]. Some of the genetic variations identified far have implications for survival and response to therapy. Mutation of isocitrate dehydrogenase (IDH) gene is associated with longer survival and O6-methylguanine-DNA methyltransferase promotor (MGMT) methylation is associated with improved response to therapy with temozolomide [6,7,8]. Growing evidence suggests that IDH mutation is a genetic marker of secondary glioblastoma arising from lower-grade astrocytoma [10] and that its presence leads to global hypermethylation [11]. Future changes to the WHO criteria are expected to further stratify patients on the basis of genetic information [12]

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