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Journal of Clinical Pathology and Laboratory Medicine | Volume 3
July 05-06, 2019 | Paris, France
Pathology and Surgical Pathology
2
nd
International Conference on
Recurrent EP300-BCOR fusions in pediatric gliomas with distinct clinicopathologic
features
Sanda Alexandrescu
Boston Children's Hospital and Harvard Medical School, USA
B
COR is an epigenetic regulator and is genetically altered by
mutation, deletion, or gene fusion in a range of cancers.
“Central nervous system high-grade neuroepithelial tumor
with BCOR alteration” is a recently described entity with
characteristic internal tandem duplications within exon 15 of
the BCOR gene (hereafter CNS HGNET-BCOR ex15 ITD). In this
case series of three patients, we report the clinicopathologic,
molecular (arrayCGH, RNA fusion analysis and targeted
exome sequencing) and methylome features of gliomas with
novel EP300-BCOR in-frame gene fusions, thus expanding
the spectrum of BCOR alterations seen in CNS tumors. The
gliomas in this series arise in children (age 10-18), involve
the supratentorial compartment and have an infiltrative
pattern of growth and a myxoid/microcystic background
with frequent psammomatous calcifications and prominent
chicken-wire vessels. All three cases had areas with low-grade
morphology and two of them demonstrated histologic high-
grade transformation. In contrast to CNS HGNET-BCOR ex15
ITD, they lack perivascular pseudorosettes. On methylation
studies and a t-distributed stochastic neighbor embedding
(tSNE) plot they cluster perfectly together, away from CNS
HGNET-BCOR ex15ITD, consistent with a different entity.
Gliomas with EP300-BCOR fusions and high-grade histology
can demonstrate relatively rapid regrowth after debulking or
subtotal resection. In conclusion, our study demonstrates
that EP300-BCOR gliomas are a unique entity and calls
for a more specific nomenclature for the existing HGNET-
BCOR, as not all BCOR-altered gliomas are high-grade.
e
:
sanda.alexandrescu@childrens.harvard.edu