title: Not infrequent K-ras mutations in depressed-type early colorectal carcinomas larger than 10 mm.
abstract: The aim of this study was to elucidate whether K-ras (codons 12 and 13) mutations occur in depressed-type early colorectal carcinomas (DECas) larger than 10 mm in size. Thirty-four cases of DECas including 27 larger than 10 mm were examined for K-ras mutations by means of microdissection, PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism), and direct sequencing. Although K-ras mutation was infrequent (1/7, 14%) in small (less than 10 mm) DECas, 16/27 (59%) and 17/27 (63%) of DECas larger than 10 mm revealed codon 12, or either codon 12 or 13 mutations, respectively. None of the evaluated pathological factors except size showed a correlation with K-ras mutation. These data indicate that although K-ras mutation could not be involved in the early stage of the progression of DECas, it might play a role at a later stage when the tumor size is over 10 mm.
authors.affiliation: First Department of Pathology, School of Medicine, Niigata University, Niigata City, PO Box 951-8510, Japan. KAZAMA-1su@h.u-tokyo.ac.jp
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Kazama
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ajioka
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Watanabe
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Nagawa
mesh_terms: D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D011905:Genes, ras; D006801:Humans; D009154:Mutation