title: Technique for differentiating alveolar soft part sarcoma from other tumors in paraffin-embedded tissue: comparison of immunohistochemistry for TFE3 and CD147 and of reverse transcription polymerase chain reaction for ASPSCR1-TFE3 fusion transcript.
abstract: The diagnosis of alveolar soft part sarcoma is commonly based on characteristic histology and distinctive periodic acid-Schiff-positive crystals; however, the characteristic crystals may not always be observed, rendering the diagnosis difficult. Three important characteristics of alveolar soft part sarcoma, the presence of ASPSCR1-TFE3 fusion transcript, nuclear immunoreactivity for TFE3, and immunoreactivity for monocarboxylate transporter 1 and CD147, have recently been reported. To identify the best marker for alveolar soft part sarcoma in formalin-fixed, paraffin-embedded tissues, we evaluated the sensitivity and specificity of the detection of the ASPSCR1-TFE3 fusion transcript along with the immunoreactivity for TFE3 and CD147 in 24 alveolar soft part sarcomas and 23 non-alveolar soft part sarcoma tumors, including 5 granular cell tumors, 5 paragangliomas, 3 clear cell sarcomas, and 10 clear cell renal cell carcinomas. The ASPSCR1-TFE3 fusion transcript was detected in 24 of 24 alveolar soft part sarcomas (7 type 1, 17 type 2), and TFE3 immunoreactivity was observed in 22 of 24 alveolar soft part sarcomas. In non-alveolar soft part sarcoma tumors, the ASPSCR1-TFE3 fusion transcript was not detected; however, the TFE3 immunoreactivity was observed in 2 of 5 granular cell tumors. CD147 immunoreactivity was demonstrated in 20 of 24 alveolar soft part sarcomas, 3 of 5 granular cell tumors, and 8 of 10 clear cell renal cell carcinomas. Our results demonstrate that the most sensitive marker of alveolar soft part sarcoma was the presence of the ASPSCR1-TFE3 fusion transcript. Thus, detection of the ASPSCR1-TFE3 fusion transcript was considered applicable for formalin-fixed, paraffin-embedded tissues with superior sensitivity as compared with TFE3 immunohistochemical staining. In alveolar soft part sarcomas with unusual locations or histology, we consider that the detection of the ASPSCR1-TFE3 fusion transcript would be the highly effective diagnostic technique.
authors.affiliation: Division of Surgical Pathology, Teikyo University Hospital, Tokyo 173-8606, Japan. danchan@med.teikyo-u.ac.jp
authors.forename: Kaori
authors.initials: K
authors.lastname: Tsuji
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Imamura
mesh_terms: D000293:Adolescent; D000328:Adult; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D051926:Basigin / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D050939:Gene Fusion; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism; D016612:Paraffin Embedding; D018234:Sarcoma, Alveolar Soft Part / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D055815:Young Adult
chemical_list: C422743:ASPSCR1 protein, human; C497886:BSG protein, human; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D047908:Intracellular Signaling Peptides and Proteins; D015514:Oncogene Proteins, Fusion; C069203:TFE3 protein, human; D051926:Basigin