Alteration of p53 tumor suppressor gene has been demonstrated in gastric adenocarcinomas. To determine the frequency of p53 expression in the primary tumors and their positive regional lymph nodes(L.Ns) in early gastric carcinomas(EGC), we studied p53 immunostaining using D07 monoclonal antibody in 108 patients with surgically resected stomach for EGC. Nuclear p53 staining was detected in carcinoma cells in 41 of 108 EGCs(38.0%), but not in normal mucosa or mucosa with intestinal metaplasia. Intestinal or mixed type EGCs (Lauren classification) showed more frequent p53-positivity(56.7%) than diffuse type EGCs (14.6%). p53-positive EGCs(34.1%) had more frequent regional LN involvement than p53- negative EGCs(13.4%). These differences were statistically significant(P=0.0005 and P=0.0l). p53 positivity was found in 8 of 23 LNs with tumor metastasis(34.8%).All patients with p53-positive LNs had p53 positivity in tumor cells of their primary tumors. This difference was also statistically significant(p = 0.005). There were no correlations between the p53 expression and age, sex, and depth of invasion. These results suggest that p53 expression occurs at a significant frequency in EGCs, especially of intestinal type and perhaps plays a role in the development and progression of these tumors.