Recurrent and novel SS18-SSX fusion transcripts in synovial sarcoma: description of three new cases

• Published in: Tumor biology Vol. 33; no. 6; pp. 2245 - 2253
• Main Authors: Przybyl, Joanna, Sciot, Raf, Rutkowski, Piotr, Siedlecki, Janusz A., Vanspauwen, Vanessa, Samson, Ignace, Debiec-Rychter, Maria
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-12-2012; Springer Nature B.V
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Amino Acid Sequence; Base Sequence; Biomarkers, Tumor - genetics; Biomedical and Life Sciences; Biomedicine; Cancer; Cancer Research; Child, Preschool; Female; Fluorescence in situ hybridization; Genes; Humans; In Situ Hybridization, Fluorescence; Intracellular Signaling Peptides and Proteins - genetics; Male; Middle Aged; Molecular biology; Molecular Sequence Data; Oncogene Proteins, Fusion - genetics; Polymerase chain reaction; Prognosis; Real-Time Polymerase Chain Reaction; Research Article; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Sarcoma, Synovial - genetics; Translocation, Genetic - genetics; Tumors; Young Adult; Fusion genes; Molecular markers; Synovial sarcoma
• ISSN: 1010-4283; 1423-0380
• DOI: 10.1007/s13277-012-0486-0

Synovial sarcoma (SS) is an aggressive type of tumor, comprising approximately 10 % of soft tissue sarcomas. Over 90 % of SS cases are characterized by the t(X;18)(p11.2;q11.2) translocation, which results mainly in the formation of oncogenic
SS18-SSX1
or
SS18-SSX2
fusions. In a typical
SS18-SSX
fusion transcript, exon 10 of
SS18
is fused to exon 6 of
SSX1/2.
However, several variant fusion transcripts have been already described. In the present study, we examined the fusion transcript type in a series of 40 primary untreated SS tumor specimens using reverse transcription polymerase chain reaction and fluorescence in situ hybridization assay. We detected
SS18-SSX1
transcript in 22 (55 %) patients and
SS18-SSX2
transcript in 17 (42.5 %) patients, while in one patient, none of
SS18
-
SSX1/2
fusion transcripts were identified. Among the cases under study, two tumors carried novel
SS18-SSX1
and
SS18-SSX2
variant translocations that were allegedly created by an alternative splicing, and in additional case, an unusual translocation variant previously described by other group was found. Our data suggest that alternative splicing may play an important role in novel fusion transcript formation, and additionally we show that it may be a recurrent event in SS. Furthermore, we describe the first case of a complex rearrangement possibly linking SS to
REPS2
gene.