DETECTION OF THE (11 22)(Q24 Q12) TRANSLOCATION OF EWINGS-SARCOMA ANDPERIPHERAL NEUROECTODERMAL TUMOR BY REVERSE TRANSCRIPTION-POLYMERASE CHAIN-REACTION

Ewing's sarcoma and the related primitive neuroectodermal tumor (PNET) share a unique and specific t(11;22)(q24;q12) chromosomal translocati on. The breakpoints have recently been cloned and shown to involve the EWS gene on chromosome 22 and the FLI-1 gene on chromosome 11. Transl ocation results in the fusion of these genes on the der(22) chromosome , resulting in the production of a novel chimeric EWS/FLI-1 message. U sing oligonucleotide primers derived from EWS and FLI-1 complementary DNAs, we were able to amplify a specific fusion transcript from 18 of 18 cases containing t(11;22) and 10 of 14 cases of Ewing's sarcoma/PNE T that had unsuccessful cytogenetics. No EWS/FLI-1 fusion transcripts were detected in five cell lines derived from cases of pediatric sarco mas having a histological diagnosis other than Ewing's sarcoma/PNET. T he sensitivity and specificity of this PCR analysis demonstrates the u sefulness of this approach for the primary diagnosis of t(11;22)-conta ining Ewing's sarcoma/PNET and for the detection of metastatic or resi dual disease.