In:
Brain Pathology, Wiley, Vol. 24, No. 3 ( 2014-04), p. 221-229
Abstract:
BRAF V600E mutation and homozygous deletion of CDKN2A ( p 16) are frequent molecular alterations in pleomorphic xanthoastrocytomas ( PXA s). We investigated 49 PXAs for clinical, histological and immunohistochemical characteristics related to BRAF mutation status. BRAF mutation was detected by immunohistochemical assay and DNA sequencing in 38/49 (78%) tumors. All but one PXA located in the temporal lobe harbored a BRAF V600E mutation (23/24; 96%) compared with 10/19 nontemporal PXAs (53%; P = 0.0009). Histological and immunohistochemical analysis demonstrated increased reticulin deposition (76% vs. 27%; P = 0.003) and a more frequent expression of CD 34 in BRAF ‐mutant PXAs (76% vs. 27%; P = 0.003). We further investigated the utility of combined BRAF V600E ( VE 1) and p 16 analysis by immunohistochemistry to distinguish PXAs from relevant histological mimics like giant‐cell glioblastoma. Among PXAs , 38/49 (78%) were VE 1‐positive, and 30/49 (61%) had a loss of p16 expression. The combined features ( VE 1 positivity/ p 16 loss) were observed in 25/49 PXAs (51%) but were not observed in giant‐cell glioblastoma ( VE 1 0/28, p 16 loss 14/28). We demonstrate that temporal location, reticulin deposition and CD 34 expression are associated with BRAF mutation in PXA . Combined VE 1 positivity and p 16 loss represents a frequent immunoprofile of PXA and may therefore constitute an additional diagnostic tool for its differential diagnosis.
Type of Medium:
Online Resource
ISSN:
1015-6305
,
1750-3639
DOI:
10.1111/bpa.2014.24.issue-3
Language:
English
Publisher:
Wiley
Publication Date:
2014
detail.hit.zdb_id:
2029927-8
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