OBJECTIVE: To investigate the expression of EWS-FLI1/ERG fusion transcript 
resulting from t(11;12)(q24;12) in paraffin-embedded tissues and its diagnostic 
implication for Ewing's sarcoma/peripheral primitive neuroectodermal tumors 
(ES/pPNET).
METHODS: One-step reverse transcriptase-polymerase chain reaction (RT-PCR) was 
employed to detect a characteristic EWS-FLI1/ERG fusion transcript in 25 cases 
of ES/pPNET and 15 cases of other small round cell tumors (including 8 cases of 
rhabdomyosarcoma, 4 cases of synovial sarcoma, 2 cases of neuroblastoma and 1 
case of lymphoma) using formalin-fixed and paraffin-embedded tissues.
RESULTS: EWS-FLI1/ERG fusion transcript was detected in 20 of the 25 ES/pPNET 
cases (80%). The 15 non-ES/pPNET control cases were negative for EWS-FLI1/ERG 
fusion transcript.
CONCLUSIONS: Detection of EWS-FLI1/ERG fusion transcript is a reliable index for 
molecular diagnosis of ES/pPNET. One-step RT-PCR is a practical method for such 
analysis in routine paraffin-embedded tumor tissues.