[Expression of cytokeratin 5 and calretinin in clear-cell renal cell carcinoma]. / Expresión de citoqueratina 5 y calretinina en el carcinoma renal de células claras.

PURPOSE: 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.

Expresión de Citoqueratina 5 y Calretinina en el carcinoma renal de células claras / Expression of cytokeratin 5 and calretinin in clear cell renal cell carcinoma

Objetivo: La citoqueratina 5 (CK5) y la calretinina se han revelado en numerosos estudios como marcadores inmunohistoquímicos sugestivos de mesotelioma y su análisis se utiliza para el diagnóstico diferencial histológico con adenocarcinomas, especialmente ante metástasis de origen desconocido. En el presente estudio hemos analizado la expresión de CK5 y calretinina en el carcinoma renal de células claras. Métodos: Se estudió un total de 63 casos de carcinoma renal de células claras. De ellos, 46 fueron incluidos en dos matrices tisulares (“tissue arrays”), y un segundo grupo, de 17 casos, estuvo constituido por bloques convencionales de tumores de alto grado (grado 4 de Fuhrman). Se realizaron tinciones inmunohistoquímicas con anticuerpos monoclonales anti CK5 y anti calretinina, mediante el método de estreptavidina marcada con peroxidasa-biotina. Resultados: No se obtuvo positividad en ninguno de los casos para calretinina, mientras que la CK5 se expresó focalmente, en células aisladas, en 1 de los 63 casos (1,59%), que correspondió a un carcinoma de alto grado (grado 4 de Fuhrman). Conclusiones: En el carcinoma renal de células claras no hemos observado expresión de calretinina y la positividad para CK5 ha ocurrido de manera aislada y en un porcentaje muy pequeño de células tumorales. Por tanto, en la práctica si bien la positividad para estos marcadores no excluye de manera absoluta carcinoma de células renales, dicho resultado es muy improbable en este tumor y obliga a considerar otras opciones diagnósticas

Purpose: 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