title: [Precancerous lesion in colorectal cancer].
abstract: Precancerous lesion in colorectal cancer was reviewed in terms of the evolution of the adenomacarcinoma sequence. K-ras codon 12 point mutation frequencies, examined in 157 adenomas, were observed in polypoid adenomas (67%) and flat adenomas (21%). Among flat adenomas, completely flat or depressed ones showed especially low mutation frequency (8%). K-ras mutation frequencies, examined in 70 invasive carcinomas, were observed in polypoid carcinomas (64%) and nonpolypoid ones (13%). From the results, it is suggested that polypoid adenomas develop into polypoid carcinomas and flat adenomas into non-polypoid carcinomas.
authors.affiliation: First Dept. of Surgery, University of Tokyo.
authors.forename: H
authors.initials: H
authors.lastname: Nagawa
authors.forename: S
authors.initials: S
authors.lastname: Yamagata
authors.forename: T
authors.initials: T
authors.lastname: Muto
mesh_terms: D000236:Adenoma / Q000235:genetics; D018256:Adenomatous Polyps / Q000235:genetics; D003111:Colonic Polyps / Q000235:genetics; D015179:Colorectal Neoplasms / Q000235:genetics*; D011905:Genes, ras; D006801:Humans; D011230:Precancerous Conditions / Q000235:genetics*