title: [Coordinated expression of cytokeratin 7 and 20 in transitional carcinoma of the bladder: diagnostic usefulness].
abstract: BACKGROUND
  Cytokeratins are intermediate filament proteins which are part of the framework of eucariotic cells. A characteristic pattern of expression of cytokeratins has been described for each type of epithelium. This pattern is maintained during the process of malignancy and metastasis. Immunohistochemical analysis of cytokeratins 7 and 20 (Ck 7 and Ck 20) has been considered particularly useful for identifying the origin of carcinomas.
  
  
  METHODS
  A total of 122 cases of transitional cell carcinoma of urinary bladder were studied immunohistochemically with monoclonal antibodies against Ck 7 and Ck 20. The peroxidase labelled-streptavidin biotin technique was performed. Cases were considered positive when at least 1% of tumoral cells were stained.
  
  
  RESULTS
  All cases investigated expressed Ck 7 whereas Ck 20 was positive in 75% of them. Reactivity for Ck 20 was always focal. No tumor was negative for Ck 7.
  
  
  CONCLUSIONS
  Ck 7+/Ck 20+ immunophenotype is highly characteristic of transitional cell carcinoma of urinary bladder, whereas Ck 7+/Ck 20- is less frequent. Immunohistochemical determination of these cytokeratins is useful for the diagnosis when tumors are poorly differentiated and for identifying the primary site of metastatic carcinomas.
authors.affiliation: Servicio de Anatomía Patológica, Centro Médico POVISA, Vigo, Pontevedra.
authors.forename: P
authors.initials: P
authors.lastname: Cid Mouteira
authors.forename: J A
authors.initials: JA
authors.lastname: Ortíz Rey
authors.forename: I
authors.initials: I
authors.lastname: Antón Badiola
authors.forename: P
authors.initials: P
authors.lastname: San Miguel Fraile
authors.forename: C
authors.initials: C
authors.lastname: Alvarez Alvarez
authors.forename: E
authors.initials: E
authors.lastname: Zungri Telo
authors.forename: A
authors.initials: A
authors.lastname: de la Fuente Buceta
mesh_terms: D002295:Carcinoma, Transitional Cell / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis / Q000096:biosynthesis*; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins / Q000032:analysis / Q000096:biosynthesis*; D001749:Urinary Bladder Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics
chemical_list: D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; C507497:KRT7 protein, human; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins