title: Malignant solitary fibrous tumor with high-grade nuclear atypia: an alternate entity for the undetermined tumor group.
abstract: Recently, a novel fusion transcript, NAB2-STAT6, and its variants have also been reported to be specific diagnostic markers for solitary fibrous tumors (SFTs). In this study, we validated the existence of the NAB2-STAT6 fusion gene in SFTs and examined its relation with the pathological features. Frozen samples from 9 tumors were assessed for fusion gene. The detected fusion genes exhibited large intron sequences and the insertion of unknown and previously unreported sequences. The fusion genes were not detected in the 2 malignant cases with high-grade nuclear atypia, nuclear pleomorphism and necrosis, that was confirmed by multiplex PCR method. In addition, 1 of the 2 NAB2-STAT6 fusion gene-negative tumors showed amplification of the MDM2 and CDK4 genes. It was suggested that a certain proportion of tumors previously diagnosed as malignant SFTs with high-grade nuclear atypia lacking NAB2-STAT6 should be categorized into a special subtype of SFT, which is genetically different from conventional SFTs, and which cannot be apparently distinguished from dedifferentiated liposarcoma or undifferentiated pleomorphic sarcoma.
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kohashi
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Bekki
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Takeaki
authors.initials: T
authors.lastname: Ishii
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Iura
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Maekawa
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yamamoto
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. Electronic address: oda@surgpath.med.kyushu-u.ac.jp.
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D050596:Oncogene Fusion; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050800:STAT6 Transcription Factor / Q000235:genetics*; D054363:Solitary Fibrous Tumor, Pleural / Q000235:genetics / Q000473:pathology; D054364:Solitary Fibrous Tumors / Q000235:genetics* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C491000:NAB2 protein, human; D015514:Oncogene Proteins, Fusion; D012097:Repressor Proteins; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human
keywords: NAB2; SFT; STAT6; Solitary fibrous tumor