The prognosis of gastric carcinoma remains unfavorable despite a greater understanding of its molecular pathology. This retrospective study of primary gastric carcinomas was collected from one of the highest risk regions of China and examined for the oncogenetic expression of p53, c-erbB-2, and PCNA using immunohistochemistry and DNA contents by flow cytometry and image analysis. These products are reported to influence the tumor behavior. The p53 nuclear and c-erbB-2 membrane-bound stainings were seen in 58% and 34% of cases, respectively. A high PCNA index was found in 90% of the tumors. The p53 expression did not correlate with the histological differentiation, gross morphology, and depth of tumor invasion. Additionally, p53 and c-erbB-2 reactivity did not correlate with the proliferative index (PI) or S-phase DNA content. However, the mutant p53 expression was detected in the dysplastic cells adjacent to the tumor, suggesting a possible role of the oncogene in tumor pathogenesis. Mutant p53 expression can also be helpful in early detection of cases with dysplasia in well-differentiated adenocarcinomas.