Elucidating the molecular pathogenesis of glioma: integrated germline and somatic profiling of a familial glioma case series.

TitleElucidating the molecular pathogenesis of glioma: integrated germline and somatic profiling of a familial glioma case series.
Publication TypeJournal Article
Year of Publication2018
AuthorsJacobs, DI, Fukumura, K, Bainbridge, MN, Armstrong, GN, Tsavachidis, S, Gu, X, Doddapaneni, H, Hu, J, Jayaseelan, JC, Muzny, DM, Huse, JT, Bondy, ML
JournalNeuro Oncol
Date Published2018 Nov 12
KeywordsAdult, Biomarkers, Tumor, Brain Neoplasms, DNA Copy Number Variations, DNA, Neoplasm, Exome, Genetic Predisposition to Disease, Genomics, Germ-Line Mutation, Glioma, Humans, Middle Aged, Prognosis

BACKGROUND: The genomic characterization of sporadically arising gliomas has delineated molecularly and clinically distinct subclasses of disease. However, less is known about the molecular nature of gliomas that are familial in origin. We performed molecular subtyping of 163 tumor specimens from individuals with a family history of glioma and integrated germline and somatic genomic data to characterize the pathogenesis of 20 tumors in additional detail.

METHODS: Immunohistochemical analyses were performed on formalin-fixed, paraffin-embedded tumor sections to determine molecular subtypes of glioma. For 20 cases, tumor DNA was exome sequenced on an Illumina HiSeq 2000 platform and copy number profiling was performed on the Illumina HumanOmniExpress BeadChip. Genotypes at glioma risk polymorphisms were determined from germline DNA profiled on the Illumina Infinium OncoArray and deleterious germline mutations were identified from germline sequencing data.

RESULTS: All 3 molecular subtypes of sporadic glioma were represented in the overall case series, including molecular glioblastoma (n = 102), oligodendroglioma (n = 21), and astrocytoma (n = 20). Detailed profiling of 20 of these cases showed characteristic subtype-specific alterations at frequencies comparable to sporadic glioma cases. All 20 cases had alterations in genes regulating telomere length. Frequencies of common glioma risk alleles were similar to those among sporadic cases, and correlations between risk alleles and same-gene somatic mutations were not observed.

CONCLUSIONS: This study illustrates that the molecular characteristics of familial tumors profiled largely recapitulate what is known about sporadic glioma and that both germline and somatic molecular features target common core pathways involved in gliomagenesis.

KEY POINTS: 1. Familial and sporadic gliomas display highly comparable molecular landscapes. 2. Germline and somatic molecular events target common core pathways involved in gliomagenesis. 3. Carriage of germline glioma risk variants is not associated with somatic events in the same gene.

Alternate JournalNeuro Oncol
PubMed ID30165405
PubMed Central IDPMC6231201
Grant ListR01 CA119215 / CA / NCI NIH HHS / United States
R01 CA139020 / CA / NCI NIH HHS / United States

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