Objective: To investigate the significance of detecting chimeric mRNA resulting from t(X;17)(p11.2;q25) in paraffin-embedded tumor tissues of alveolar soft part sarcoma (ASPS).
Methods: Formalin-fixed, paraffin-embedded tumor tissues from 8 cases of alveolar soft part sarcoma and 15 cases of controls (including 6 alveolar rhabdomyosarcomas, 6 renal cell carcinomas, 2 paragangliomas and 1 granular cell myoblastoma) were retrieved from the archival materials. ASPL-TFE3 fusion transcripts were analyzed in all samples by reverse transcriptase-polymerase chain reaction (RT-PCR). The quality of the mRNA was assessed using the house-keeping gene beta-actin.
Results: ASPL-TFE3 fusion transcripts were detected in 6 of the 8 ASPS cases (4 being type 2 and 2 being type 1). The remaining 2 cases were negative for both beta-actin and ASPL-TFE3. No ASPL-TFE3 mRNA expression was detected in all the controls. PAX3/7-FKHR fusion transcripts were also detected in 4 of the 6 alveolar rhabdomyosarcoma samples.
Conclusions: The expression of ASPL-TFE3 fusion transcripts in paraffin-embedded tumor tissues can serve as an useful molecular marker in the diagnosis of ASPS. It may also be helpful in elucidating the underlying pathogenesis of ASPS in subsequent retrospective studies.