BACKGROUND The growth pattern of early gastric carcinoma, based on a volumetric analysis, reflects well biologic characteristics of the tumor. The penetrating growth (Pen) type tumor has an unfavorable prognosis, compared with a superficially spreading (Super) type. Abnormality of the p53 suppressor gene plays an important role in alteration of cells leading to development of cancer. p53 point mutations are present even in an early stage of carcinoma. METHODS In 159 patients with early gastric carcinoma, overexpression of p53 was studied immunohistochemically, using a monoclonal antibody (PAb 1801), and the relationship between growth pattern and p53 overexpression was analyzed. RESULTS Early gastric carcinoma was grouped into 43 of the Super type, 37 of the expansively penetrating growth (Pen-A) type, 16 of the infiltratively penetrating growth (Pen-B) type, and 63 of the Small mucosal type limited to the mucosal layer. The Pen-A type tumors were characterized by the highest incidence of p53 positive expression and poorest postoperative course. Between the Pen-A type and the Super type, there were significant differences in the incidence of the p53 positive expression (43% vs. 16%), the frequency of recurrence (16% vs. 7%), and disease free interval (574 days vs. 2926 days). CONCLUSIONS The authors' observations show that the p53 gene plays an important role in expansion of gastric carcinoma, even in the early stages.