ABSENCE OF RAS MUTATIONS AND LOW INCIDENCE OF P53 MUTATIONS IN RENAL-CELL CARCINOMAS INDUCED BY FERRIC NITRILOTRIACETATE

Renal cell carcinomas induced in male Wistar rats by iron chelate of n itrilotriacetate (Fe-NTA) were examined for mutations in ras oncogenes and p53 tumor suppressor gene. Fourteen primary tumors and two metast atic tumors from 11 animals were evaluated. Exons 1 and 2 of the H-, K -, and N-ras genes were amplified by polymerase chain reaction (PCR), and the presence of mutations was examined by direct sequencing. Exon 5 through exon 7 of p53 gene, including the 3' half of the conserved r egion II and the entire conserved region III through V, were surveyed for point mutations by PCR-single stranded conformation polymorphism ( SSCP) analysis. Direct sequencing of the ras genes showed no mutations in codon 12, 13, or 61 among the tumors evaluated. SSCP analysis of p 53 gene exon 6 indicated conformational changes in two primary tumors. One tumor had a CCG-to-CTG transition at codon 199, and the other had an ATC-to-ATT transition at codon 229 and two nonsense C-to-T transit ions. These results suggest that neither ras genes nor p53 gene play a major role in the development of renal cell carcinomas induced by Fe- NTA.