title: Overexpression of human H-ras transgene is responsible for tumors induced by chemical carcinogens in mice.
abstract: Level of human prototype H-ras transgene expression in tumors induced by chemical carcinogens (N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea) was analyzed in human H-ras transgenic mice (CB6F1-TgrasH2 Jic mice). All forestomach tumors examined revealed about 2-fold overexpression of the human H-ras transgene with or without point mutation at codon 12 or codon 61. However, endogenous mouse H- and K-ras genes exhibited neither point mutation nor overexpression. These results suggested that increased levels of ras gene products in the cell played an important role in facilitating chemical carcinogenesis in transgenic mice.
authors.affiliation: Central Institute of Experimental Animals, Kawasaki-shi, Kanagawa 216-0001, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Maruyama
authors.forename: M
authors.initials: M
authors.lastname: Tomisawa
authors.forename: S
authors.initials: S
authors.lastname: Wakana
authors.forename: H
authors.initials: H
authors.lastname: Yamazaki
authors.forename: H
authors.initials: H
authors.lastname: Kijima
authors.forename: H
authors.initials: H
authors.lastname: Suemizu
authors.forename: Y
authors.initials: Y
authors.lastname: Ohnishi
authors.forename: K
authors.initials: K
authors.lastname: Urano
authors.forename: K
authors.initials: K
authors.lastname: Hioki
authors.forename: T
authors.initials: T
authors.lastname: Usui
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Tsuchida
authors.forename: K
authors.initials: K
authors.lastname: Mitsumori
authors.forename: T
authors.initials: T
authors.lastname: Nomura
authors.forename: N
authors.initials: N
authors.lastname: Tamaoki
authors.forename: Y
authors.initials: Y
authors.lastname: Ueyama
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D005038:Ethylnitrosourea / Q000633:toxicity; D005784:Gene Amplification; D011905:Genes, ras; D008770:Methylnitrosourea / Q000633:toxicity; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D016283:Proto-Oncogene Proteins p21(ras) / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000139:chemically induced* / Q000235:genetics* / Q000473:pathology
chemical_list: D002273:Carcinogens; D008770:Methylnitrosourea; D016283:Proto-Oncogene Proteins p21(ras); D005038:Ethylnitrosourea