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4
H3 K27Mmutation
19
• Defines a subgroup of diffuse intrinsic pontine gliomas
• Mutation in histone protein -> epigenetic implications
BuczkowiczP etal,NatureGenetics2014
20
2016
What happened to Oligoastrocytoma?
21
Oligoastrocytoma
Astrocytoma
Oligodendroglioma
Difficulttodefine
High interobserver discordance
22
Oligoastrocytoma
Oligoastrocytoma
23
• Using phenotype & genotype (i.e.,
IDH
mutation and 1p19q
codeletion) allows to allocate them to either astrocytic or
oligodendroglial subtypes
• Discordant results of phenotype & genotype ->
genotype
trumps histological phenotype!
• Introduction of „not otherwise specified, NOS“
Is genotype alone sufficient for diagnosis?
24
• At this point in time:
No
• WHO grading is still based on histologic criteria
• Challenges with respect to testing and reporting
• Availability & choice of genotyping or surrogate genotyping assays