Biological significance of c-met over expression in papillary renal cell carcinoma.

Abstract

Hereditary papillary renal cell carcinoma is associated with mutations of the c-met proto-oncogene. Similar aberrations have been described at a molecular level in up to 13% of sporadic papillary renal cell carcinomas. We assessed c-met expression in papillary renal cell carcinomas and evaluated the prognostic significance of c-met expression in patients with this tumor. We performed immunohistochemical testing to identify c-met expression in archival specimens of 55 papillary renal cell carcinomas in 51 patients. Only 1 patient reported a family history of renal malignancy. We identified c-met protein expression in the cytoplasm and cell membrane of 80% and 56% of these tumors, respectively. c-met expression significantly correlated with higher stage tumors (p = 0.004) but it was not associated with Fuhrman nuclear grade (p = 0.157). A trend toward a higher overall survival rate was noted in patients in whom tumors did not express c-met but this association failed to achieve statistical significance (p = 0.07). Our study indicates that c-met over expression may be associated with an aggressive phenotype in these tumors.