Detection of TLS/FUS-CHOP fusion transcripts
in a case of oral liposarcoma
Elena Riet Correa Rivero, MDS, PhD
, Ricardo Alves Mesquita, PhD
Suzana Cantanhede Orsini Machado de Sousa, PhD
, Fabio Daumas Nunes, PhD
Department of Oral Pathology, School of Dentistry, University of Sa˜o Paulo, 05508-900 Sa˜o Paulo, Brazil
Department of Oral Pathology, School of Dentistry, University of Minas Gerais, 31270-901 Belo Horizonte, Brazil
Abstract Objective: The aim of this study was to detect the chromosomal translocation t(12;16)(q13;p11)
that leads to a gene fusion encoding a FUS-CHOP chimeric protein and has been shown to be
highly characteristic of myxoid and round cell subtypes of liposarcoma, in a case of oral
Method and Materials: Nested reverse transcriptase–polymerase chain reaction to detect the TLS/
FUS-CHOP fusion gene transcript was performed. A case of inflammatory fibrous hyperplasia and a
case of oral lipoma were included as negative controls.
Results: Only the myxoid oral liposarcoma showed a 103–base pair product, specific of TLS/FUS-
CHOP fusion type II transcript.
Conclusion: The identification of FUS-CHOP transcript is potentially useful in the diagnosis and
research of oral liposarcomas.
D 2006 Elsevier Inc. All rights reserved.
Keywords: Chromosomal translocation; Cancer development; FUS-CHOP chimeric protein; Liposarcomas; RT-PCR; TLS/
FUS-CHOP fusion gene
Liposarcoma is the most common soft tissue sarcoma in
adults, and the thigh, retroperitoneum, and inguinal region
are the most common sites [1,2]. Diagnosis of the lip-
osarcoma is achieved with the use of the immunohisto-
chemical and morphological analysis. The histological
classification of these tumors includes myxoid, well
differentiated, round cell, pleomorphic, and dedifferentiated
. Oral liposarcomas are very rare, with 48 cases reported
in the literature. Most are myxoid or well-differentiated type
and localized in buccal mucosa or tongue [2 -5].
Myxoid and round cell liposarcomas are characterized by
the t(12;16)(q13;p11) translocation [6,7]. This translocation
leads to the fusion of CHOP (12q13) and FUS (16p11)
genes generating a FUS/CHOP hybrid protein. The CHOP
gene codes for a nuclear protein that belongs to the CCAAT/
enhancer binding protein family of transcription factors. The
FUS, also named TLS, gene codes for a nuclear RNA
binding protein that interacts with serine-arginine proteins
involved in RNA splicing and that is able to promote
homologous DNA pairing, which is a key step in
homologous recombination . The TLS/FUS-CHOP fu-
sion protein can behave as a transcription activator and
possesses transforming activity in vitro [9,10].
Approaches to detect the t(12;16)(q13;p11) transloca-
tion are useful for differential diagnosis to other sarcomas,
especially if applicable to formalin-fixed paraffin-embedded
tissues . This report presents the detection of the
TLS/FUS-CHOP fusion gene transcript in an oral myxoid
2. Method and materials
A case of oral myxoid liposarcoma, 1 inflammatory
fibrous hyperplasia, and 1 oral lipoma fixed in 10% neutral
formalin solution and embedded in paraffin were retrieved
1092-9134/$ – see front matter D 2006 Elsevier Inc. All rights reserved.
T Corresponding author. Tel.: +55 11 3091 7902; fax: +55 11 3818 7894.
E-mail address: email@example.com (F.D. Nunes).
Annals of Diagnostic Pathology 10 (2006) 36 –38