Expression of the ras oncoprotein in gastric carcinomas and adjacent mucosa.

We have employed an immunohistochemical analysis to study the ras p21 oncoprotein in a total of 88 gastric carcinomas, which were associated (in 24 cases) with intestinal metaplasia. Our results suggest an association of the expression of ras p21 with metaplastic and neoplastic gastric mucosa. The comparative study showed that 58 of the 88 gastric carcinoma cases studied exhibited negative or equivocal staining (-/+). The remaining 30 were positive with moderate (+) or intense (++) staining. There was an agreement in that histologic type and tumor grade had a strict correlation with staining intensity. Intestinal metaplasia had a higher percentage of positively stained cells (+ or ++). Moreover, there was a selective positive staining in the parietal cells of the gastric fundus in sections from adjacent non-neoplastic mucosa.