title: Rare occurrence of ras and p53 gene mutations in mouse stomach tumors induced by N-methyl-N-nitrosourea.
abstract: The incidence of point mutations of H-, K- and N-ras and p53 oncogenes in male BALB/c mouse stomach tumors induced with N-methyl-N-nitrosourea (MNU) was examined by direct sequencing and PCR single-strand conformation polymorphism (PCR-SSCP). A mutation of GGT to AGT at K-ras codon 12 was found by SSCP in one adenocarcinoma from a total of 19 specimens including 5 adenocarcinomas, 9 adenomatous hyperplastic regions, 1 squamous cell carcinoma and 4 normal-like stomach regions from 4 mice. No mutations were detected by direct sequencing of H-, K- and N-ras oncogenes at exons 1 (codons 12 and 13) and 2 (codon 61) in a total of 26 specimens comprising 10 adenocarcinomas, 10 adenomatous hyperplastic regions, 2 squamous cell carcinomas and 4 normal-like stomach regions from 6 mice. No mutations were detected by direct sequencing of p53 oncogene at exons 5, 6, 7 and 8 in a total of 30 specimens including 13 adenocarcinomas, 8 adenomatous hyperplastic regions, 2 squamous cell carcinomas, 1 papilloma and 6 normal-like stomach regions from 7 mice. These results suggest that ras and p53 oncogenes do not play a role in mouse stomach carcinogenesis induced by MNU.
authors.affiliation: Department of Molecular Oncology, University of Tokyo, Minato-ku.
authors.forename: C
authors.initials: C
authors.lastname: Furihata
authors.forename: M
authors.initials: M
authors.lastname: Tatematsu
authors.forename: M
authors.initials: M
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Ishida
authors.forename: H
authors.initials: H
authors.lastname: Nakanishi
authors.forename: K
authors.initials: K
authors.lastname: Inada
authors.forename: H
authors.initials: H
authors.lastname: Tei
authors.forename: M
authors.initials: M
authors.lastname: Hattori
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Sakaki
mesh_terms: D000236:Adenoma / Q000139:chemically induced / Q000235:genetics; D000818:Animals; D002277:Carcinoma / Q000139:chemically induced / Q000235:genetics*; D016158:Genes, p53; D011905:Genes, ras; D008297:Male; D008770:Methylnitrosourea; D051379:Mice; D008807:Mice, Inbred BALB C; D016296:Mutagenesis; D013274:Stomach Neoplasms / Q000139:chemically induced / Q000235:genetics*
chemical_list: D008770:Methylnitrosourea