A novel type of EWS–CHOP fusion gene in myxoid liposarcoma

The cytogenetic hallmark of myxoid type and round cell type liposarcoma consists of reciprocal translocation of t(12;16)(q13;p11) and t(12;22)(q13;q12), which results in fusion of TLS/FUS and CHOP, and EWS and CHOP, respectively. Nine structural variations of the TLS/FUS–CHOP chimeric transcript have been reported, however, only two types of EWS–CHOP have been described. We describe here a case of myxoid liposarcoma containing a novel EWS–CHOP chimeric transcript and identified the breakpoint occurring in intron 13 of EWS. Reverse transcription-polymerase chain reaction and direct sequence showed that exon 13 of EWS was in-frame fused to exon 2 of CHOP. Genomic analysis revealed that the breaks were located in intron 13 of EWS and intron 1 of CHOP.