title: SYT-SSX fusion genes in synovial sarcoma of the thorax.
abstract: Synovial sarcoma (SS) is characterized by a chromosomal translocation resulting in the expression of an SYT-SSX chimeric transcript, usually SYT-SSX1 or SYT-SSX2. Synovial sarcoma typically originates in the limbs, and its location in the thorax is rare. Synovial sarcomas are usually classified into three histologic subtypes: biphasic, monophasic and poorly differentiated tumors. The detection of the characteristic chimeric transcript often contributes to a histopathological diagnosis, especially when the tumor arises in an unusual location. Previous studies have shown that SYT-SSX1 is the most common SYT-SSX fusion transcript in biphasic synovial sarcomas of the limbs. Here, we report two cases of synovial sarcoma originating in the thorax. The presence of SYT-SSX2 chimeric transcripts was confirmed by reverse transcript polymerase chain reaction (RT-PCR) and a direct sequencing analysis in both cases. The tumor in case 1 originated from the pericardium, which is an exceedingly rare site for primary synovial sarcoma; only three other cases of synovial sarcoma originating in the pericardium have been previously reported. Case 2 exhibited a biphasic synovial sarcoma of the mediastinum containing an SYT-SSX2 fusion transcript, which is a rare fusion type in biphasic synovial sarcomas of the limbs. We reviewed previous reports of thoracic synovial sarcomas containing an analysis of the SYT-SSX fusion transcript and found that case 2 in the present study was the first description of a biphasic synovial sarcoma of the thorax with an SYT-SSX2 fusion transcript. However, the number of reported cases was not sufficient to conclude that SYT-SSX2 fusion in biphasic synovial sarcoma of the thorax is, indeed, rare. Further genetic analysis is needed to fully understand the biological and clinical features of synovial sarcoma originating in the thorax.
authors.affiliation: Department of Cancer and Thoracic Surgery, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikatacho, Okayama 700-8558, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yano
authors.forename: Shinichi
authors.initials: S
authors.lastname: Toyooka
authors.forename: Kazunori
authors.initials: K
authors.lastname: Tsukuda
authors.forename: Hideaki
authors.initials: H
authors.lastname: Dote
authors.forename: Yuki
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Norihide
authors.initials: N
authors.lastname: Ohata
authors.forename: Kouichi
authors.initials: K
authors.lastname: Ichimura
authors.forename: Motoi
authors.initials: M
authors.lastname: Aoe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Date
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Shimizu
mesh_terms: D000293:Adolescent; D005260:Female; D006801:Humans; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins / Q000235:genetics*; D013584:Sarcoma, Synovial / Q000235:genetics*; D013899:Thoracic Neoplasms / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D011506:Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; C093961:SS18 protein, human; C093962:synovial sarcoma X breakpoint proteins