Myxoid liposarcoma with EWS-CHOP type 1 fusion gene.
BACKGROUND
In myxoid liposarcoma (MLS), the t(12;16)(q13;p11) chromosomal translocation and its resultant fusion transcript, the human translocation liposarcoma (TLS)-CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP), are found in the majority of cases. On the other hand, the variant translocation, t(12;22)(q13;q12) creating the Ewing sarcoma (EWS)-CHOP fusion transcript, is detectable in a limited number of cases.


METHODS
Tissue from MLS arising in the left thigh of a 19-year-old female was analyzed for possible detection of chromosome translocation and fusion transcript. Fluorescent in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR) methods were used.


RESULTS
FISH analysis demonstrated a rearrangement in the CHOP gene. RT-PCR analysis confirmed the presence of EWS-CHOP chimeric transcript type 1, in which exon 7 of EWS was in-frame fused to exon 2 of CHOP with a serine (AGT) to methionine (ATG) transition at the junction. The patient underwent a radical segmental resection including a left vastus medialis musclectomy. Sixty months following the surgical resection, the patient was alive with no evidence of disease.


CONCLUSIONS
Analysis of MLS with EWS-CHOP variant transcripts, type 1 through type 4, including this case together with 15 cases in the literature, indicated that MLS with type 1 fusion transcript may show a more favorable clinical behavior than MLS with other types of fusion transcript.
Departments of Orthopaedic Surgery, University of Toyama, Toyama 930-0194, Japan.
Kayo
K
Suzuki
Yoshito
Y
Matsui
Kenji
K
Endo
Takahiro
T
Kubo
Tadashi
T
Hasegawa
Tomoatsu
T
Kimura
Osamu
O
Ohtani
Natsuo
N
Yasui
D000328:Adult; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018208:Liposarcoma, Myxoid / Q000175:diagnosis* / Q000235:genetics*; D008279:Magnetic Resonance Imaging; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D034802:RNA-Binding Protein EWS / Q000235:genetics*; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051742:Transcription Factor CHOP / Q000235:genetics*; D014158:Transcription, Genetic; D014178:Translocation, Genetic; D055815:Young Adult
C497249:DDIT3 protein, human; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; D034802:RNA-Binding Protein EWS; D051742:Transcription Factor CHOP