Establishment and characterization of two cultured cell lines derived from malignant rhabdoid tumors of the kidney.

Malignant rhabdoid tumor of the kidney (RTK) is a rare renal sarcoma of childhood. Its histogenesis is unclear, and it is highly resistant to multimodality therapy. To elucidate the origin and the oncogenetic potential of RTK, we investigated the characteristics of 2 newly established RTK cell lines, SWT-1 and SWT-2. Both cell lines were verified to be RTK, since they did not exhibit contact inhibition and exhibited intermediate filaments, a specific marker for RTK. These cells possess the characteristics of mesenchymal cells based on their positive reactions with anti-vimentin and anti-laminin antibodies and their negative reactions with anti-keratin and anti-desmin antibodies. The karyotype of SWT-1 was 46,XX and that of SWT-2 was 46,XX,del(11)(pter-p13::p12-qter). Since 11p13 is the location of the WT-1 tumor-suppressor gene, and del(11p13) is associated with the aniridia-Wilms'-tumor syndrome, these findings link RTK with Wilms' tumor. While SWT-1 was negative for the tumor markers examined, SWT-2 released tissue polypeptide antigen into the culture supernatant. No rearrangement or amplification of the myc and ras oncogenes or of the p53 tumor-suppressor gene were detected. Wild-type RB protein and cyclin A were expressed in both cells. Our data suggest that these 2 cell lines may be useful in identifying the oncogenetic pattern of RTK.