Genetic, Epigenetic, and Immunologic Profiling of MMR-Deficient Relapsed Glioblastoma.
Clin Cancer Res
; 25(6): 1828-1837, 2019 03 15.
Article
em En
| MEDLINE
| ID: mdl-30514778
ABSTRACT
PURPOSE:
In-depth characterization of recurrent glioblastoma (rGBM) might contribute to a better understanding of the mechanisms behind tumor progression and enable rGBM treatment with targeted drugs.ExperimentalDesign:
In this study, GBM samples were collected at diagnosis and recurrence from adult patients treated with Stupp protocol. Expression of mismatch repair (MMR) proteins was evaluated by IHC, followed by whole exome sequencing (WES) of tumor samples showing loss of MSH6 reactivity. Established genetic, epigenetic, and immunologic markers were assessed by standard methods and correlated with loss of MMR proteins and patient survival.RESULTS:
Expression of MMR proteins was partially or completely lost in 25.9% rGBM samples. Specifically, 12 samples showed partial or total MSH6 expression reduction. Conversely, 96.4% of GBM samples at diagnosis expressed MMR markers. WES disclosed lack of variants in MMR genes in primary samples, whereas two MSH6-negative rGBM samples shared a c.3438+1G>A* splicing MSH6 variant with a potential loss of function effect. MSH6-negative rGBM specimens had high tumor mutational burden (TMB), but no microsatellite instability. In contrast, GBM samples with partial loss of MMR proteins disclosed low TMB. MMR-deficient rGBM showed significant telomere shortening and MGMT methylation and are characterized by highly heterogeneous MHC class I expression.CONCLUSIONS:
Multilevel profiling of MMR-deficient rGBM uncovered hypermutated genotype uncoupled from enriched expression of immune-related markers. Assessment of MHC class I expression and TMB should be included in protocols aiming to identify rGBM patients potentially eligible for treatment with drugs targeting immune-checkpoint inhibitors.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Encefálicas
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Biomarcadores Tumorais
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Glioblastoma
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Reparo de Erro de Pareamento de DNA
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Recidiva Local de Neoplasia
Tipo de estudo:
Guideline
/
Observational_studies
Limite:
Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Clin Cancer Res
Assunto da revista:
NEOPLASIAS
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Itália