title: Detection of ki-ras mutation in nonneoplastic mucosa of Japanese patients with colorectal cancers.
abstract: About 50% of colorectal adenocarcinoma in humans have been reported to contain mutated Ki-ras gene. To provide a better understanding for the possible role of this mutation and to examine whether its presence can reliably predict a risk of colorectal cancer, we have analyzed the normal appearing mucosa of patients with colorectal adenocarcinoma. With an Enriched PCR procedure, we can detect mutated Ki-ras allele in the presence of 10(3) to 10(4) normal alleles. Only by this procedure was Ki-ras mutation detected in the non-neoplastic colonic mucosa of 9 out of 50 (18%) Japanese patients with colorectal cancer. This analysis indicated that epithelial cells which carry mutated Ki-ras gene were 100- to 1000-fold less frequent in the non-neoplastic mucosa than at the tumor site. The presence of ras gene mutation in normal appearing mucosa points to a previous exposure which had initiated the multistage process of colorectal carcinogenesis.
authors.affiliation: NATL CANC CTR,RES INST,DIV BIOCHEM,5-1-1 TSUKIJI,CHUO KU,TOKYO 104,JAPAN. NATL CANC CTR,RES INST,DIV PATHOL,CHUO KU,TOKYO 104,JAPAN. AMER HLTH FDN,MOLEC CARCINOGENESIS PROGRAM,VALHALLA,NY 10595. KANAZAWA UNIV,CANC RES INST,DEPT SURG,KANAZAWA,ISHIKAWA 921,JAPAN.
authors.forename: T
authors.initials: T
authors.lastname: Minamoto
authors.forename: Z
authors.initials: Z
authors.lastname: Ronai
authors.forename: N
authors.initials: N
authors.lastname: Yamashita
authors.forename: A
authors.initials: A
authors.lastname: Ochiai
authors.forename: T
authors.initials: T
authors.lastname: Sugimura
authors.forename: M
authors.initials: M
authors.lastname: Mai
authors.forename: H
authors.initials: H
authors.lastname: Esumi