GENO-28ANALYSIS OF NAB2-STAT6 GENE FUSION IN 17 CASES OF MENINGEAL SOLITARY FIBROUS TUMOR/HEMANGIOEPRICYTOMA

Abstract

BACKGROUND: Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a mesenchymal tumor that can affect virtually any region of the body. SFT/HPC occurred in thoracic cavity and soft tissue has been considered a single biological entity termed SFT with characteristic NAB2-STAT6 gene fusion in both of them. Meanwhile meningeal SFT and HPC are still categorized into discrete disease entities, thus still to be investigated in detail, especially for genetic background. The aim of this study is to verify the frequency of NAB2-STAT6 gene fusion and the relationship between fusion variants and clinicopathological findings of SFT/HPC, especially meningeal SFT/HPC. METHODS: We examined the NAB2-STAT6 gene fusion by reverse transcription-PCR with 4 case of meningeal SFT and 13 cases of HPC which were histologically diagnosed. For the detection of the NAB2-STAT6 fusion gene, seven types of forward primers in NAB2 ({"type":"entrez-nucleotide","attrs":{"text":"NM_005967.3","term_id":"95102542","term_text":"NM_005967.3"}}NM_005967.3) and six types of reverse primers in STAT6 ({"type":"entrez-nucleotide","attrs":{"text":"NM_001178078.1","term_id":"296010863","term_text":"NM_001178078.1"}}NM_001178078.1) were designated. RT-PCR of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as endogenous control. All of the detected NAB2-STAT6 fusion variants were confirmed by Sanger sequencing. RESULTS: We identified fusion genes in 12 out of 17 cases including NAB2 exon 6 – STAT6 exon 17 (4/17, 24%), NAB2 exon 6 – STAT6 exon 16 and NAB2 exon 4 – STAT6 exon 2 (3/17, 18%, respectively). In addition, we also identified the novel fusion genes NAB2 exon 5 – STAT6 exon 16 including two types of fusion variation. CONCLUSIONS: Our results confirmed that meningeal STF and HPC are in a single biological spectrum with NAB2-STAT6 gene fusion as well as non-meningeal SFT/HPC. Moreover, the fact that the major fusion variant in the meningeal SFT/HPC was NAB2 exon 6 – STAT6 exon 16/17, which were in rare in thoracic SFT/HPC might suggest the oran specific tumorigenic procell of SFT/HOC.