Synovial sarcoma specific translocation associated with both epithelial and spindle cell components.

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Synovial sarcoma is a soft tissue sarcoma characterized by specific genetic translocations.
• Biphasic synovial sarcoma exhibits both epithelial and spindle cell components, raising questions about their cellular origin and relationship.

Purpose of the Study:

• To investigate the presence and distribution of the synovial sarcoma-specific genetic rearrangement in both cellular components of biphasic synovial sarcoma.
• To provide genetic evidence for the clonal nature of biphasic synovial sarcoma.

Main Methods:

• Utilized a recently developed 2-color fluorescence in situ hybridization (FISH) methodology.
• Analyzed paraffin-embedded tissue from 3 biphasic synovial sarcoma cases with varying proportions of epithelial and spindle cells.

Main Results:

• Successfully detected the synovial sarcoma-specific der(X)t(X;18)(p11.2;q11.2) translocation involving the SSX1 gene.
• The genetic rearrangement was identified in both the epithelial/glandular and spindle cell components within each tumor.
• Confirmed the presence of the rearrangement in histologically defined regions.

Conclusions:

• Biphasic synovial sarcomas are clonal in origin, with both cellular components arising from a single precursor cell.
• The study provides direct genetic evidence supporting the truly biphasic nature of these tumors.