Detection of SYT-SSX fusion gene transcripts in synovial sarcoma and its correlation with histological phenotypes

Objective To detect SYT-SSX fusion gene transcripts in fresh-frozen synovial sarcoma specimens and analyze the correlation between histological phenotypes and SYT-SSX subtypes. Methods Fresh-frozen specimens from 19 synovial sarcoma patients were studies from July 2000 to September 2004. SYT-SSX fusion gene and its subtypes were determined by RT-PCR. Simultaneously, definite pathological diagnoses were made and histological phenotypes were confirmed. The correlation between histological phenotype and SYT-SSX subtypes were analyzed.Results SYT-SSX fusion gene was detected in 15 cases(79%) and SYT-SSX1 and SYT-SSX2 was detected in 11 and 4 cases respectively. A rare variant of SYT-SSX2 was found. All these 15 cases were definitely confirmed as synovial sarcoma histologically and SYT-SSX fusion gene was detected in all these cases. 10 monophasic cases and 4 biphasic cases and 1 poorly differentiated case were confirmed and SYT-SSX2 did not exist in biphasic cases.Conclusions RT-PCR is a highly sensitive and specific method in detecting SYT-SSX fusion gene and that is specific for synovial sarcoma. To preserve fresh-frozen specimen and detect fusion gene by RT-PCR with proper primers is meaningful to clinical diagnosis as well as to basic research.