[Roles of immunohistochemistry and detection of SYT-SSX fusion gene in diagnosis of synovial sarcoma].
OBJECTIVE
To assess the diagnostic values of immunohistochemistry and SYT-SSX fusion gene detection for synovial sarcoma.


METHODS
Based on clinical features, histological and immunohistochemical profiles, 195 cases of tumors were divided into three diagnostic categories: definitive synovial sarcoma, probable synovial sarcoma and possible synovial sarcoma. RT-PCR Detection of the SYT-SSX fusion gene was performed using paraffin embedded tissue samples. Comparison between RT-PCR and immunohistochemistry results was carried out and their diagnostic value was evaluated.


RESULTS
There were 62 (31.8%) definite synovial sarcomas, 49 (25.1%) probable synovial sarcomas and 84 cases (43.1%) possible synovial sarcomas. SYT-SSX fusion gene was detected in 140 (78.2%) cases overall, including 94.7% (54/57) definite synovial sarcomas, 86.0% (37/43) probable synovial sarcomas and 62.0% (49/79) possible synovial sarcomas. In tumors in the certain and probable synovial sarcoma categories, the positive rates of epithelial membrane antigen (EMA) were significantly higher in the SYT-SSX positive cases than SYT-SSX-negative cases (P = 0.022, P = 0.010, respectively). EMA was positively correlated with the presence of SYT-SSX (r(s) = 0.431, P = 0.001, r(s) = 0.463, P = 0.002, respectively). However, such a correlation was not seen in cytokeratin (CK), vimentin or S-100 protein immunostains (P > 0.05). In tumors of possible synovial sarcoma category, there were no significant differences of CK, EMA, vimentin or S-100 protein between SYT-SSX-positive and SYT-SSX-negative tumors.


CONCLUSIONS
SYT-SSX fusion gene detection is not needed when the conventional approaches are diagnostic. EMA positivity has a similar diagnostic value to that of SYT-SSX by RT-PCR for tumors in the probable synovial sarcoma category. However, detection of SYT-SSX is very important for diagnosis of the tumors in the category of possible synovial sarcoma.
Sun
Yan
Y
Department of Pathology, Tianjin Cancer Hospital, Tianjin 300060, China.
Sun
Bao-cun
BC
Zhao
Xiu-lan
XL
Wang
Jian
J
Chen
Jing
J
Li
Xiao-qing
XQ
Feng
Yu-mei
YM
Fang
Zhi-wei
ZW
Hao
Xi-shan
XS
D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018396:Mucin-1 / Q000378:metabolism*; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009418:S100 Proteins / Q000378:metabolism; D013584:Sarcoma, Synovial / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D014746:Vimentin / Q000378:metabolism; D055815:Young Adult
D014408:Biomarkers, Tumor; D018396:Mucin-1; D015514:Oncogene Proteins, Fusion; D009418:S100 Proteins; C116512:SYT-SSX fusion protein; D014746:Vimentin; D007633:Keratins