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Title: Mutations of the K-ras and p53 genes in gastric adenocarcinomas from a high-incidence region around Florence, Italy.
Authors: Hongyo T,  Buzard GS,  Palli D,  Weghorst CM,  Amorosi A,  Galli M,  Caporaso NE,  Fraumeni JF Jr,  Rice JM
Journal: Cancer Res
Date: 1995 Jun 15
Branches: ITEB, OD
PubMed ID: 7780983
PMC ID: not available
Abstract: K-ras and p53 gene mutations in intestinal-type gastric carcinomas from a high-incidence area around Florence, Italy, were studied by single strand conformation polymorphism and DNA sequencing analysis. Single-strand conformation polymorphism analysis of K-ras indicated aberrant bands in 13 of 34 cases. Sequencing revealed point mutations in 7 (including two at a previously unreported site in codon 11), a significantly higher frequency than reported in countries other than Japan. No K-ras mutations were identified in stage III tumors. Single-strand conformation polymorphisms in p53 exons 5-8 occurred in 30 of 34 cases, with mutations identifiable by direct sequencing in 65% of the cases. Of these, 91% were base substitutions, a value similar to that usually reported, but the percentage of G:C to A:T transitions (90% in this study, 89% in all published European cases combined) differed significantly from that in Oriental cases (48%). The percentage of A:T to G:C transitions was greater in Oriental (22%) than European cases (2%), as was also true for transversions (30% in Oriental tumors, 9% in European tumors). The frequency of mutations at CpG sites (14%) varied significantly from the 67% in cases from a neighboring region in Italy. Helicobacter pylori infection was established in 19 cases and was somewhat more common in cases lacking a p53 mutation.