Dataset Information

Chromosome 17p Homodisomy Is Associated With Better Outcome in 1p19q Non-Codeleted and IDH-Mutated Gliomas.

ABSTRACT:

Background

The 1p19q non-codeleted gliomas with IDH mutation, defined as "molecular astrocytomas," display frequent TP53 mutations and have an intermediate prognosis. We investigated the prognostic impact of copy number-neutral loss of heterozygosity (CNLOH) in 17p in this population.

Methods

We analyzed 793 gliomas (206 grade II, 377 grade III, and 210 grade IV) by single nucleotide polymorphism array and for TP53 mutations.

Results

Homodisomy revealed by CNLOH was observed in 156 cases (19.7%). It was more frequent in astrocytomas and oligoastrocytomas (98/256, 38%) than oligodendrogliomas (28/327, 8.6%; p < .0001) or glioblastoma multiforme (30/210, 14.3%; p < .0001), tightly associated with TP53 mutation (69/71 vs. 20/79; p = 2 × 10(-16)), and mutually exclusive with 1p19q codeletion (1/156 vs. 249/556; p < .0001). In the group of IDH-mutated 1p19q non-codeleted gliomas, CNLOH 17p was associated with longer survival (86.3 vs. 46.2 months; p = .004), particularly in grade III gliomas (overall survival >100 vs. 37.9 months; p = .007). These data were confirmed in an independent dataset from the Cancer Genome Atlas.

Conclusion

CNLOH 17p is a prognostic marker and further refines the molecular classification of gliomas.

Implications for practice

Homodisomy of chromosome 17p (CNLOH 17p) is a frequent feature in IDH-mutated 1p19q non-codeleted gliomas (group 2). It is constantly associated with TP53 mutation. It was found, within this specific molecular group of gliomas (corresponding to molecular astrocytomas), that CNLOH 17p is associated with a much better outcome and may therefore represent an additional prognostic marker to refine the prognostic classification of gliomas.

SUBMITTER: Labussiere M

PROVIDER: S-EPMC5016064 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature

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Publications

Chromosome 17p Homodisomy Is Associated With Better Outcome in 1p19q Non-Codeleted and IDH-Mutated Gliomas.

Labussière Marianne M Rahimian Amithys A Giry Marine M Boisselier Blandine B Schmitt Yohann Y Polivka Marc M Mokhtari Karima K Delattre Jean-Yves JY Idbaih Ahmed A Labreche Karim K Alentorn Agusti A Sanson Marc M

The oncologist 20160708 9

<h4>Background</h4>The 1p19q non-codeleted gliomas with IDH mutation, defined as "molecular astrocytomas," display frequent TP53 mutations and have an intermediate prognosis. We investigated the prognostic impact of copy number-neutral loss of heterozygosity (CNLOH) in 17p in this population.<h4>Methods</h4>We analyzed 793 gliomas (206 grade II, 377 grade III, and 210 grade IV) by single nucleotide polymorphism array and for TP53 mutations.<h4>Results</h4>Homodisomy revealed by CNLOH was observe ...[more]

PMID: 27401888

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Project description:ObjectiveLGGs (low-grade gliomas) are sometimes encountered by chance during radiological examinations. These incidentally discovered LGGs (IDLGGs) were relatively under-studied in the literature. The purpose of current study is to review a cohort of patients with IDLGGs surgically treated in our institution for their clinical and histological aspects and determine their IDH1 and 1p19q status.MethodsAll patients with hemispheric LGGs receiving operation in our institution between 2001 and 2004 were reviewed. Clinical, radiological and treatment data of the patients were collected and IDLGGs were retrieved and compared with symptomatic LGGs. Histological review was carried out and formalin-fixed paraffin embedded (FFPE) tissues of IDLGGs were examined for IDH1/IDH2 mutation and 1p/19q codeletion.ResultsTwenty three IDLGGs (10.4%) were identified while 196 patients had symptomatic LGGs. The reasons for patients with IDLGGs having radiological examination included trauma (47.8%), dizziness (26.1%), unrelated headache (21.7%), and health checkup (4.4%). Clinically, patients with IDLGGs had higher preoperative KPS (P < 0.001), smaller tumor volume (P = 0.014), lower frequency of eloquent areas involvement (P < 0.001) and higher rate of complete resection (P = 0.037) comparing to those with symptomatic LGGs. Histologically, there is a preponderance of oligodendroglial differentiation with 6 oligodendrogliomas and 11 oligoastrocytomas but there were also 6 astrocytomas. IDH1 mutation and 1p/19q co-deletion were detected in 95.7% (22/23) and 69.6% (16/23) of IDLGGs, respectively. The latter encompassed all but one of the cases of oligodendroglial tumors. Patients with IDLGGs had longer overall survival than those with symptomatic LGGs (P = 0.027).ConclusionsWe conclude that the majority of IDLGGs are IDH1 mutated and are predominantly oligodendroglial tumors. With a median follow-up of 9.3 years to our series, we conclude that patients with IDLGGs had better prognosis than those with symptomatic LGGs. The favorable prognosis of IDLGGs may be accounted by the higher practicability of extensive resection, non-eloquent tumor location and smaller tumor volume. Frequent IDH1 mutation and 1p/19q co-deletion in IDLGGs may also contribute to the favorable prognosis of this subgroup of patients.

Project description:BackgroundThis study aimed to assess the validity and pathophysiology of the T2/FLAIR-mismatch sign for noninvasive identification of isocitrate dehydrogenase (IDH)-mutant 1p/19q non-codeleted glioma.MethodsMagnetic resonance imaging scans from 408 consecutive patients with newly diagnosed glioma (113 lower-grade gliomas and 295 glioblastomas) were evaluated for the presence of T2/FLAIR-mismatch sign by 2 independent reviewers. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the performance of the T2/FLAIR-mismatch sign for identifying IDH-mutant 1p/19q non-codeleted tumors. An exploratory analysis of differences in contrast-enhancing tumor volumes, apparent diffusion coefficient (ADC) values, and relative cerebral blood volume (rCBV) values in IDH-mutant gliomas with versus without the presence of a T2/FLAIR-mismatch sign (as well as analysis of spatial differences within tumors with the presence of a T2/FLAIR-mismatch sign) was performed.ResultsThe T2/FLAIR-mismatch sign was present in 12 cases with lower-grade glioma (10.6%), all of them being IDH-mutant 1p/19q non-codeleted tumors (sensitivity = 10.9%, specificity = 100%, PPV = 100%, NPV = 3.0%, accuracy = 13.3%). There was a substantial interrater agreement to identify the T2/FLAIR-mismatch sign (Cohen's kappa = 0.75 [95% CI, 0.57-0.93]). The T2/FLAIR-mismatch sign was not identified in any other molecular subgroup, including IDH-mutant glioblastoma cases (n = 5). IDH-mutant gliomas with a T2/FLAIR-mismatch sign showed significantly higher ADC (P < .0001) and lower rCBV values (P = .0123) as compared to IDH-mutant gliomas without a T2/FLAIR-mismatch sign. Moreover, in IDH-mutant gliomas with T2/FLAIR-mismatch sign the ADC values were significantly lower in the FLAIR-hyperintense rim as compared to the FLAIR-hypointense core of the tumor (P = .0005).ConclusionsThis study confirms the high specificity of the T2/FLAIR-mismatch sign for noninvasive identification of IDH-mutant 1p/19q non-codeleted gliomas; however, sensitivity is low and applicability is limited to lower-grade gliomas. Whether the higher ADC and lower rCBV values in IDH-mutant gliomas with a T2/FLAIR-mismatch sign (as compared to those without) translate into a measurable prognostic effect requires investigation in future studies. Moreover, spatial differences in ADC values between the core and rim of tumors with a T2/FLAIR-mismatch sign potentially reflect specific distinctions in tumor cellularity and microenvironment.

Dataset Information

Chromosome 17p Homodisomy Is Associated With Better Outcome in 1p19q Non-Codeleted and IDH-Mutated Gliomas.

Background

Methods

Results

Conclusion

Implications for practice

Publications

Chromosome 17p Homodisomy Is Associated With Better Outcome in 1p19q Non-Codeleted and IDH-Mutated Gliomas.

Similar Datasets

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