Open AccessDemonstration of ras and p53 Gene Mutations in Carcinomas in the Forestomach and Intestine and Soft Tissue Sarcomas Induced by N ‐Methyl‐ N ‐nitrosourea in the Rat
Author(s) -
Matsumoto Kazuyuki,
Iwase Teruhiko,
Hirono Iwao,
Nishida Yoshihisa,
Iwahori Yoshio,
Hori Takaaki,
Asamoto Makoto,
Takasuka Nobuo,
Kim Dae Joong,
Ushijima Toshikazu,
Nagao Minako,
Tsuda Hiroyuki
Publication year - 1997
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1997.tb00357.x
Subject(s) - exon , biology , adenocarcinoma , single strand conformation polymorphism , microbiology and biotechnology , gene , mutation , pathology , gene mutation , point mutation , cancer research , cancer , genetics , medicine
The presence of ras family and p53 gene mutations in rat forestomach, intestine and liver tumors and soft tissue sarcomas induced by N methyl‐ N ‐nitrosourea (MNU) was examined using polymerase chain reaction‐single strand conformation polymorphism (PCR‐SSCP) followed by direct sequencing analysis. In the forestomach squamous cell carcinomas (SCC), Ha‐ ros and p53 mutations were detected in 2 (40%) and 4 (80%) of 5 cases, respectively. The figures for Ki‐ ras and p53 gene mutations in adenocarcinomas of the large and small intestines were 3 (18.8%) and 5 (31.3%) of 16 cases. Soft tissue sarcomas in different sites were found to have mutations of Ki‐ ras in 7 (23.3%)and of p53 in 9 (30%) of 30 cases. One forestomach SCC and 2 soft tissue sarcomas had double p53 mutations in different exons. Single cases of forestomach SCC and intestinal adenocarcinoma had mutations in both Ki‐ ras and p53 genes. No mutations were found in counterpart benign tumors or hepatocellular adenomas. The p53 mutation spectrum revealed preferential clustering within exon 8 for the forestomach SCCs, and exons 5 and 8 for the intestinal adenocarcinomas, whereas the distribution was evenly spread through exons 5 to 8 in soft tissue sarcomas. All the detected ras or p53 mutations were G:C to A:T transitions. These results indicate firstly that specific Ki‐ ras , Ha‐ ras and p53 gene mutations in MNU‐induced lesions are related to particular alkylation sites (G:C to A:T transitions) and secondly, although not essential, Ki‐ ras , Ha‐ ras or p53 gene mutations may be involved in the progression stage of forestomach, intestine and soft tissue neoplasms induced by MNU.