The t(11.22)(q24.q12) results in expression of a chimeric RNA product, EWS-FLI1. This RNA product is expressed in over 85% of tumours belonging to the Ewing's family, and is increasingly used as a definitive characteristic of these tumours. In this study, we evaluated reverse transcriptase-polymerase chain (RT-PCR) for EWS-FLI1 fusion transcripts in 18 neurally derived small round cell tumours. These included six Ewing's family tumours and 12 neuroblastomas. EWS-FLI1 fusion transcripts were identified in all six Ewing's tumours, but also in two of the 12 neuroblastomas. One neuroblastoma contained the classic type 1 fusion transcript, and the second a type 1 transcript containing a 66 bp (base pair) insert that was not derived from the EWS or FLI1 gene. The presence of EWS-FLI1 fusion products in RNA extracted from primary neuroblastoma suggests the identification of EWS-FLI1 fusion transcripts is not pathognomonic for tumours of the Ewing's family. The clinical significance of these fusion transcripts in neuroblastoma is not known.

DOI: 10.1016/S0959-8049(96)00463-7
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