Fusion of the RBP56 and CHN genes in extraskeletal myxoid chondrosarcomas with translocation t(9;17)(q22;q11)

Although most extraskeletal myxoid chondrosarcomas (EMC) are cytogeneticall y characterized by the translocation t(9;22)(q22;q12), another subset has r ecently been identified carrying a t(9;17)(q22;q11). Whereas the t(9;22) is known to result in fusion of the CHN (TEC) gene from 9q22 with the EWS gen e from 22q12, creating a chimeric EWS/CHN, the genes involved in the t(9;17 ) of EMC are unknown. We examined two EMC with t(9;17)(q22;q11) and found t hat the CHN gene was recombined with the RBP56 gene from 17q11 to generate a chimeric RBP56/CHN, RBP56 has not previously been shown to be involved in tumorigenesis but it encodes a putative RNA-binding protein similar to the EWS and FUS (TLS) proteins known to play a pathogenetic role in several sa rcomas, The presence of the RBP56/CHN chimeric gene in EMC with t(9;17)(q22 ;q11) shows that the N-terminal parts of EWS and RBP56 have similar oncogen ic potential making them pathogenetically equivalent in oncoproteins arisin g from fusions with certain transcription factors.