Multiparameter analysis of four human renal cell carcinoma xenografts in nude mice

Four human renal cell carcinoma xenografts (RC2, RC14, RC43, NC65), maintained in nude mice for several years, were investigated in a multi - disciplinary study, using (immuno) histochemical, biochemical and ultrastructural techniques. Histological, cellular, nuclear and biological characteristics were investigated. All tumors showed histologically recognizable features of human renal cell carcinomas, although marked differences between the four tumors were seen, both at the histological and ultrastructural level. Flowcytometric analysis of tumor cell suspensions allowed DNA quantification as well as the detection of subpopulations. Immunohistochemical staining procedures using tissue specific antibodies against intermediate filament proteins revealed two populations of tumor cells. Most tumor cells in three of the xenografts coexpressed cytokeratins and vimentin, while in RC43 most of the tumor cells expressed only vimentin. Northern blot analysis showed a higher expression of vimentin mRNA in all tumors as compared to normal kidney tissue. RC43 showed a three-fold higher level of vimentin mRNA than the other xenografts. Growth potential in the human tumor cloning system was evaluated by temporal growth pattern analysis. These experiments showed that the xenografts resemble human primary renal cell tumors in different ways, and reflect different characteristics that can be present in human renal cell carcinoma.