Rhabdoid tumors of the kidney contain mesenchymal specific and epithelial specific intermediate filament proteins.

The intermediate filament proteins of rhabdoid tumors of the kidney were investigated with a panel of monoclonal antibodies to different intermediate filament proteins. Rhabdoid tumor cells are decorated by an antivimentin antibody and by an antibody made against a 54-kilodalton (kd) cytokeratin from human hepatoma cells. The rhabdoid tumor cells fail to react with an antibody generated against keratin from stratum corneum or with an anti-200-kd neurofilament protein antibody. Cytoskeleton preparations of rhabdoid tumor cells grown in vitro demonstrate the presence of vimentin (58 kd) and the 54-kd cytokeratin. Thus, these cells contain two different intermediate filament proteins characteristic of epithelial and mesenchymal cells. We also demonstrate that rhabdoid tumor cells can form tumors in athymic (nude) mice and that the intracytoplasmic globules are present in the nude mouse lesions.