Résumé
To determine the chronology of oncogenes in gastric carcinogenesis, we studied oncoproteins of c-Ha/Ki/N-ras, c-erbB-2, and pan-myc in gastric malignant and premalignant lesions of Wistar rats induced by MNNG using im-munohistochemistry. c-ras p21 cytoplasmic staining was seen in 7/23 (30.4%) of gastric adenocarcinomas and found to correlate with the staging of lesions. c-erbB-2 p185 cellular membrance staining was observed in 17/33 (51.5%) and pan-myc p62, in 33/39 (84.6%) chronic atrophic gastritis. The highest positive rate of the concomitant expression of these genes was observed in adenocarcinomas (17.4%). Higher expression level of these three oncoproteins were found in the antral area than those in the fundic area, expression of the three oncogenes was found in adenocarcinomas (17.4%) (P