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.
Mots-clés Pascal : Epithélioma glandulaire, Estomac, Tumeur maligne, Pathogénie, Homme, Gène onc, Gène suppresseur tumeur, Mutation ponctuelle, Helicobacter pylori, Spirillaceae, Spirillales, Bactérie, Epidémiologie moléculaire, Estomac pathologie, Appareil digestif pathologie, Italie, Europe, Gène K-Ras, Gène ras, Gène p53
Mots-clés Pascal anglais : Adenocarcinoma, Stomach, Malignant tumor, Pathogenesis, Human, Onc gene, Tumor suppressor gene, Point mutation, Helicobacter pylori, Spirillaceae, Spirillales, Bacteria, Molecular epidemiology, Gastric disease, Digestive diseases, Italy, Europe
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0399895
Code Inist : 002B13B01. Création : 01/03/1996.