GRIA2 is a novel diagnostic marker for solitary fibrous tumour identified through gene expression profiling. Issue 1 (2nd April 2014)

• Record Type: Journal Article
• Authors: Vivero, Marina; Doyle, Leona A; Fletcher, Christopher D M; Mertens, Fredrik; Hornick, Jason L
• Is Part Of: Histopathology. Volume 65:Issue 1(2014)
• Page Start: 71
• Page End: 80
• Publication Date: 2014-04-02
• Subjects: Histology, Pathological -- Periodicals; 611.018
• DOI: 10.1111/his.12377
• Languages: English
• ISSNs: 0309-0167

Abstract

<abstract abstract-type="main" id="his12377-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="his12377-sec-0001" sec-type="section"> <title>Aims</title> <p>The <italic>NAB2–STAT6</italic> fusion was recently identified as a consistent finding in solitary fibrous tumour (SFT), resulting in nuclear expression of the C‐terminal part of STAT6. Gene expression studies of SFT revealed high expression of the <italic>GRIA2</italic> gene. The aim of this study was to examine GRIA2 expression in SFTs and other soft tissue tumours to evaluate its diagnostic utility.</p> </sec> <sec id="his12377-sec-0002" sec-type="section"> <title>Methods and results</title> <p>Immunohistochemistry was performed on 375 soft tissue tumours. In total, 84 of 105 (80%) SFTs, including 86% of malignant SFTs and 100% of dedifferentiated SFTs, were positive for GRIA2. One SFT known to harbour the <italic>NAB2–STAT6</italic> fusion but that was negative for STAT6 by immunohistochemistry was positive for GRIA2. It is of note that 93% of SFTs received in the last 3 years were positive for GRIA2, as compared with only 70% of older cases. The only other tumours that expressed GRIA2 were 15 of 20 (75%) cases of dermatofibrosarcoma protuberans (DFSP), four of nine (44%) myoepitheliomas, one synovial sarcoma (<1% of cells), and one schwannoma.</p> </sec> <sec id="his12377-sec-0003" sec-type="section"> <title>Conclusions</title> <p>GRIA2 is a useful marker for distinguishing SFT from most mimics. Among other CD34‐positive tumours, GRIA2 is also expressed in DFSP; however, clinical and histological features aid in their distinction. GRIA2 shows a limited distribution in other soft tissue tumours.</p> </sec> </abstract>