Expression of oncogenes during chemical gastrocarcinogenesis in rats
Deng Dajun, Gu Liankun, Zhu Shaoxia, et al. Beijing Institute for Cancer Research and School of Oncology, Beijing Medical University, Beijing, 100034
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%) (P0.05). These results suggest that the increased ras expression may be important throughout the course of MNNG-induced gastric carcinogenesis and overexpression of c-erbB-2 and pan-myc may be an early events in gastric carcinogenic sequence.