Oligoastrocytomas: throwing the baby out with the bathwater?
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Recently in this journal, Sahm and colleagues advised “parting with the diagnosis of OA (oligoastrocytoma)”, based on genetic analyses of 43 putative OA tumours . Here we present our viewpoint that the majority of tumours tested by Sahm et al. were not true OAs, and that the entity of OA, whilst uncommon, remains a valuable diagnosis. We describe two cases of OA that exhibit lineage-associated molecular alterations restricted to only a proportion of tumour cells. These cases demonstrate that molecular heterogeneity in a subset of OAs is real, with important implications for our understanding of fundamental glioma biology, clinical trial design, and future treatment decisions. OA should not be ignored in the proposed new classification guidelines .
Sahm and colleagues studied 43 cases diagnosed as OA based on histology. But in 30 of these cases, immunostaining for IDH1 (R132H) mutation was restricted to oligodendroglial areas only. The astrocytic component of these tumours was...
KeywordsTP53 Mutation Mutant IDH1 Oligodendroglial Tumour Molecular Heterogeneity Mixed Glioma
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