Not all 1p/19q non-codeleted oligodendroglial-like tumors are astrocytic
Refereed conference paper presented and published in conference proceedings

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AbstractAlthough combined chromosomal 1p and 19q deletion is the genetic hallmark defining oligodendrogliomas, approximately 30% to 40% of oligodendroglial tumors have intact 1p/19q as shown in most international series and demonstrate aggressive clinical course. This group of 1p/19q intact oligodendroglial tumors is frequently suggested to be derived from astrocytic lineage and remains as an under-investigated entity. In the present study, we provided evidence that not all 1p/19q intact oligodendroglial tumors are of astrocytic lineage through histologic and molecular approaches. We examined 1p/19q status by interphase fluorescence in-situ hybridization in a large cohort of 337 oligodendroglial tumors collected from Prince of Wales Hospital (Hong Kong) and Huashan Hospital (Shanghai), and identified 134 cases (39.8%) lacking 1p/19q codeletion which was independently associated with poor prognosis across the cohort by multivariate analysis. Among this 1p/19q intact oligodendroglial tumor cohort, 58 cases (43.3%) demonstrated classic oligodendroglial histology which showed older patient age (p=0.01), better prognosis (p<0.000001), association with grade III histology (p=0.009), PDGFRA expression (p=0.019), TERTp mutation (p=0.007), as well as frequent IDH mutation. More than half of the 1p/19q intact oligodendroglial tumors showed lack of astrocytic defining markers, p53 immunoexpression and ATRX loss, indicating their non-astrocytic phenotype molecularly. TP53 mutational analysis was additionally conducted in a subset (45 cases) of the 1p/19q intact oligodendroglial tumors. Wild-type TP53 was detected in 32 cases (71.1%) which was associated with classic oligodendroglial histology (p=0.045). Importantly, IDH and TERTp co-occurred in 75% of 1p/19q intact, TP53 wild-type oligodendrogliomas (p=0.012), highlighting the potential of the co-mutation in assisting diagnosis of oligodendroglioma in tumor with clear cell morphology and non-codeleted 1p/19q status. In summary, our study demonstrated that not all 1p/19q intact oligodendroglial tumors are astrocytic and co-evaluation of IDH and TERTp mutation could potentially serve as an adjunct for diagnosing 1p/19q intact oligodendroglioma.
All Author(s) ListChan AK, Li YX, Shi ZF, Aibaidula A, Chen H, Li KK, Chan DT, Poon WS, Mao Y, Ng HK
Name of Conference12th Meeting of the European-Association-of-Neuro-Oncology
Start Date of Conference12/10/2016
End Date of Conference16/10/2016
Place of ConferenceMannheim
Country/Region of ConferenceGermany
Journal nameNeuro-Oncology
Proceedings TitleNeuro-Oncology
Detailed descriptionTo ORKTS: No
Volume Number18
Issue NumberSuppl 4
PublisherOxford University Press
Pages12 - 12
LanguagesEnglish-United Kingdom
Web of Science Subject CategoriesClinical Neurology; Neurosciences & Neurology; Oncology

Last updated on 2021-26-09 at 02:48