Detection of the synovial sarcoma translocation t(X;18) (SYT;SSX) in paraffin-embedded tissues using reverse transcriptase-polymerase chain reaction: a reliable and powerful diagnostic tool for pathologists. A molecular analysis of 221 mesenchymal tumors fixed in different fixatives.
Synovial sarcoma (SS) is a relatively rare sarcoma, which may be confused with several other mesenchymal and nonmesenchymal lesions. It bears the t(X;18) (SYT;SSX) translocation, which seems to be specific for this tumor type and can be detected in paraffin-embedded tissue, using reverse transcriptase-polymerase chain reaction (RT-PCR). However, the specificity and sensitivity of this detection method have rarely been examined in a large series. Using RT-PCR, we examined 250 mesenchymal and nonmesenchymal, benign and malignant, paraffin-embedded lesions for the SS t(X;18) (SYT-SSX) translocation. PCR products were obtained from 221 tumors (88.5%). There were 135 non-SS tumors, 22 biphasic, and 64 monophasic spindle/round cell SS, of which 10 were cytogenetically confirmed as t(X;18)-positive. SYT-SSX gene fusion transcripts were detected in the SS tumor category only (100% specificity), including 100% of the biphasic SS and 86% of monophasic spindle/round cell SS. Nine tumors originally diagnosed as SS were t(X;18) (SYT-SSX)-negative. Following reassessment, only 3 of these tumors showed clinicopathologic, immunohistochemical, and/or ultrastructural features consistent with that diagnosis, thus raising the overall detection sensitivity to 96%. With regard to the potential adverse effect of the fixatives used, PCR products were obtained in 100%, 91.5%, 90.5%, and 0% of tumors fixed with AFA, buffered formalin, Holland Bouin, and conventional Bouin's fluid, respectively. This study shows that the detection of the SS t(X;18) (SYT-SSX) in paraffin-embedded tissue is feasible with a 100% specificity and an overall 96% sensitivity, provided non-Bouin's fluid fixation is used.
Guillou
L
L
University Institute of Pathology, Lausanne, Switzerland.
Coindre
J
J
Gallagher
G
G
Terrier
P
P
Gebhard
S
S
de Saint Aubain Somerhausen
N
N
Michels
J
J
Jundt
G
G
Vince
D R
DR
Collin
F
F
Trassard
M
M
Le Doussal
V
V
Benhattar
J
J
D000328:Adult; D014408:Biomarkers, Tumor; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D005404:Fixatives; D006801:Humans; D008297:Male; D008875:Middle Aged; D018204:Neoplasms, Connective and Soft Tissue / Q000235:genetics / Q000473:pathology; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D016612:Paraffin Embedding; D010338:Pathology, Clinical; D012334:RNA, Neoplasm / Q000235:genetics; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013584:Sarcoma, Synovial / Q000235:genetics / Q000473:pathology*; D014178:Translocation, Genetic; D014960:X Chromosome / Q000235:genetics*
D014408:Biomarkers, Tumor; D018076:DNA, Complementary; D005404:Fixatives; D015514:Oncogene Proteins, Fusion; D012334:RNA, Neoplasm; C116512:SYT-SSX fusion protein