Molecular diagnosis of synovial sarcoma: RT-PCR detection of SYT-SSX1/2 fusion transcripts in paraffin-embedded tissue.
BACKGROUND
Synovial sarcomas comprise up to 10 percent of malignant soft tissue tumors, and most are characterized by the chromosomal translocation t(X;18) (pl 1.2;q11.2), which results in the expression of SYT-SSX fusion transcripts. These tumors include two major histological subtypes, biphasic and monophasic. Diagnosing biphasic synovial sarcomas does not usually pose a problem, whereas the monophasic spindle-cell form can be difficult to distinguish from other spindle-cell neoplasms using histological and immunohistochemical profiles only.


METHODS
We investigated the presence of SYT-SSX1/2 chimeric RNA in tumors from 7 patients. We applied amplification of the specific fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) in fresh, frozen tumors. We also developed a method useful for RT-PCR SYT-SSX fusion transcript detection in formalin-fixed, paraffin-embedded tissue.


RESULTS
We found that both histological subtypes of synovial sarcoma were SYT-SSX positive. Moreover, we observed a correlation between histological subtype and type of SYT-SSX fusion transcript. Biphasic synovial sarcoma expressed the SYT-SSX1 fusion transcript, whereas the monophasic subtype expressed the SYT-SSX2 fusion transcript.


CONCLUSIONS
The detection of SYT-SSX1/2 fusion transcripts by RT-PCR is a valuable diagnostic marker of synovial sarcoma which can be used for the reclassification of cases whose diagnosis is difficult by routine methods.
Tvrdík
Daniel
D
Institute of Pathology, General Faculty Hospital, Studnickova 2, Prague 2, 128 00, Czech Republic. Daniel.Tvrdik@vfn.cz
Povýsil
Ctibor
C
Svatosová
Jana
J
Dundr
Pavel
P
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics; D002887:Chromosomes, Human, Pair 18; D041321:Chromosomes, Human, X; D018153:Czech Republic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D016612:Paraffin Embedding; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013584:Sarcoma, Synovial / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D014158:Transcription, Genetic; D014178:Translocation, Genetic
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; C116512:SYT-SSX fusion protein