title: Diagnosis of clear cell sarcoma by real-time reverse transcriptase-polymerase chain reaction analysis of paraffin embedded tissues: clinicopathologic and molecular analysis of 44 patients from the French sarcoma group.
abstract: BACKGROUND
  Clear cell sarcoma (CCS) is a rare tumor with a very poor prognosis that occurs predominantly in the distal extremities of young adults. Most patients bear the t(12;22) reciprocal translocation, which involves the EWS and ATF1 genes. The diagnosis of CCS usually is easy but may be challenging in unusual sites, and the detection of EWS-ATF1 fusion transcripts is helpful to rule out a metastatic melanoma.
  
  
  METHODS
  Forty-four patients with CCS and 14 conventional melanomas were examined for the presence of EWS-ATF1 transcripts by using real-time polymerase chain reaction (PCR) analysis on paraffin embedded tissues, including frozen samples for 9 CCS samples and 9 melanoma samples. Prior to molecular analysis, the diagnosis of CCS was considered certain in 35 patients and as probable in 9 patients on the basis of location, histologic features, and immunohistochemical profile. Treatment modalities and follow-up were available for 41 patients with CCS.
  
  
  RESULTS
  EWS-ATF1 fusion transcripts were detected in 38 paraffin embedded CCS tissues (86% of all samples; 93% of interpretable samples), 3 samples (7%) were negative, and 3 samples (7%) were considered uninterpretable. Fusion transcripts were detected in 7 of 9 samples for which the diagnosis of CCS was considered probable. EWS-ATF1 transcripts were not detected in the 14 samples of melanoma. Results from frozen tissues were concordant with those from all corresponding paraffin embedded samples. Twenty-eight of 41 patients (68%) experienced lymph node and/or distant metastasis, and the 5 year-survival rate was 44%. Mitotic index and histologic grade were predictive of survival and distant metastasis.
  
  
  CONCLUSIONS
  The results of this study showed that the molecular detection of EWS-ATF1 fusion transcript by real-time PCR on paraffin embedded tissues is a sensitive and specific method for the diagnosis of CCS. It is an efficient tool for the diagnosis of unusual tumors, especially with regard to its distinction from melanoma. The current results also confirmed the poor prognosis for patients with this tumor type. Mitotic index and grade were predictive factors for survival and distant metastasis.
authors.affiliation: Department of Pathology, Institut Bergonie, Bordeaux, France. coindre@bergonie.org
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Coindre
authors.forename: Isabelle
authors.initials: I
authors.lastname: Hostein
authors.forename: Philippe
authors.initials: P
authors.lastname: Terrier
authors.forename: Corinne
authors.initials: C
authors.lastname: Bouvier-Labit
authors.forename: Francoise
authors.initials: F
authors.lastname: Collin
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Michels
authors.forename: Martine
authors.initials: M
authors.lastname: Trassard
authors.forename: Bernard
authors.initials: B
authors.lastname: Marques
authors.forename: Dominique
authors.initials: D
authors.lastname: Ranchere
authors.forename: Louis
authors.initials: L
authors.lastname: Guillou
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003199:Computer Systems; D005260:Female; D005602:France; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000175:diagnosis; D015514:Oncogene Proteins, Fusion / Q000032:analysis / Q000235:genetics*; D016612:Paraffin Embedding; D011379:Prognosis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D018227:Sarcoma, Clear Cell / Q000175:diagnosis* / Q000235:genetics; D016019:Survival Analysis; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics*
chemical_list: C111598:EWS-ATF1 fusion protein, human; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors