title: Alveolar Soft Part Sarcoma.
abstract: Alveolar soft part sarcoma is a rare neoplasm usually arising in the soft tissues of the lower limbs in adults and in the head and neck region in children. It presents primarily as a slowly growing mass or as metastatic disease. It is characterized by a specific chromosomal alteration, der(17)t(X:17)(p11:q25), resulting in fusion of the transcription factor E3 (TFE3) with alveolar soft part sarcoma critical region 1 (ASPSCR1) at 17q25. This translocation is diagnostically useful because the tumor nuclei are positive for TFE3 by immunohistochemistry. Real-time polymerase chain reaction to detect the ASPSCR1-TFE3 fusion transcript on paraffin-embedded tissue blocks has been shown to be more sensitive and specific than detection of TFE3 by immunohistochemical stain. Cathepsin K is a relatively recent immunohistochemical stain that can aid in the diagnosis. The recent discovery of the role of the ASPSCR1-TFE3 fusion protein in the MET proto-oncogene signaling pathway promoting angiogenesis and cell proliferation offers a promising targeted molecular therapy.
authors.forename: Omar I
authors.initials: OI
authors.lastname: Jaber
authors.affiliation: From the Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Kirby
mesh_terms: D000328:Adult; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D002648:Child; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D041321:Chromosomes, Human, X / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism; D000090063:Proto-Oncogene Mas; D018234:Sarcoma, Alveolar Soft Part / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D014178:Translocation, Genetic
chemical_list: C422743:ASPSCR1 protein, human; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D047908:Intracellular Signaling Peptides and Proteins; C000715470:MAS1 protein, human; D015514:Oncogene Proteins, Fusion; D000090063:Proto-Oncogene Mas; C069203:TFE3 protein, human