title: [Expression of cytokeratin 5 and calretinin in clear-cell renal cell carcinoma].
abstract: OBJECTIVE
  Cytokeratin 5 (CK5) and calretinin have been useful in different studies as immunohistochemical markers suggestive of mesothelioma, and their expression is analyzed for the histological differential diagnosis with adenocarcinomas, specially when confronting with metastatic tumors of unknown origin. We have analyzed the expression of CK5 and calretinin in clear cell renal cell carcinoma.
  
  
  METHODS
  A series of 63 clear cell renal cell carcinomas was studied. 46 of these cases were embedded in two tissue arrays, and a second group, of 17 cases, was constituted by conventional paraffin blocks from high-grade tumors (grade 4 of Fuhrman). Immunohistochemical staining was performed with monoclonal antibodies against CK5 and calretinin, following the labeled sptreptavidin-biotin technique.
  
  
  RESULTS
  No positivity for calretinin was observed in any case, while CK5 was focally expressed, in an isolated group of cells, in 1 of the 63 cases (1,59%) which corresponded to a high-grade carcinoma (grade 4 of Fuhrman).
  
  
  CONCLUSIONS
  Expression of calretinin was not observed in clear cell renal cell carcinoma and positivity for CK5 occurred only in one case, in a very small proportion of tumor cells. Therefore, in practice, although the positivity for these markers cannot completely exclude renal cell carcinoma, this result is very rare in this tumor and other diagnostic posibilities should be considered.
authors.affiliation: Servicio de Anatomía Patológica, Hospital Povisa, Vigo (Pontevedra).
authors.forename: P
authors.initials: P
authors.lastname: Cid Mouteira
authors.forename: J A
authors.initials: JA
authors.lastname: Ortiz-Rey
authors.forename: C
authors.initials: C
authors.lastname: Gómez de Maria
authors.forename: P
authors.initials: P
authors.lastname: San Miguel Fraile
authors.forename: A
authors.initials: A
authors.lastname: Albor Barroso
authors.forename: B
authors.initials: B
authors.lastname: Regueiro Parcero
authors.forename: I
authors.initials: I
authors.lastname: Antón Badiola
mesh_terms: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000032:analysis*; D064032:Calbindin 2; D002292:Carcinoma, Renal Cell / Q000737:chemistry* / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D007124:Immunoenzyme Techniques; D007680:Kidney Neoplasms / Q000737:chemistry* / Q000473:pathology; D008654:Mesothelioma / Q000737:chemistry / Q000473:pathology; D009363:Neoplasm Proteins / Q000032:analysis*; D016612:Paraffin Embedding; D064030:S100 Calcium Binding Protein G / Q000032:analysis*; D013048:Specimen Handling / Q000379:methods
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; C576764:CALB2 protein, human; D064032:Calbindin 2; D009363:Neoplasm Proteins; D064030:S100 Calcium Binding Protein G